# minimal Audio specifications



## informel (Jun 21, 2011)

Ok lets open a can of worms.

The audio market is such a mess, manufacturer are playing with number and make them meaningless or sometime they gave you no number at all (like Bose)

I would like to know what do you think would be the minimal or acceptable specification for different audio and why not video gear.

I will start this up with speakers (cabinet not drivers)

Sensivity: in DB/watt/meter (giving sensivity in DB with no reference means nothing)
frequency response: lower limit - upper limit @ -3DB ex: 40hz - 40Khz @-3DB
maybe the radiation patern, but I am not sure this would be use by a lot of people

amplifier
power is frequently given for one channel at 1Khz
I beleive it would be better to have at least the power bandwith ex. 105W from 10hz to 40Khz
and possibly power all channels driven simultaniously

give your input on that

minimal spec for receiver I am not asking about how many HDMI input and output a receiver should have, but just the spec so we can compare.

Like a reference when they say that a receiver can put out 105W per channel, put a standard (like distortion level, but they should all have the same reference for example number of watt @ .1% distortion

you can add other gears with spec

Please keep it cool, not sure manufacturer will check this tread, so be cool and do not start a fire


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## Guest (Dec 21, 2011)

Almost all speakers have specs listed. Bose is the only I know that doesn't.

As far as amps and AVRs go, I do wish their could be some SAE standards or something. Some are under rated, some are over rated. It's a mess.

Without any standards though, the information on quality equipment is out their. Not really fair to the normal consumer who isn't really in to all of it. On the other hand, it is so easy to do research now days.


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## jackfish (Dec 27, 2006)

The FTC has regulations which specify the minimum criteria for test conditions and reporting of amplifier power ratings. It provides for multichannel amplifier sine wave continuous average power output ratings based on two channels driven into the specified impedance at 1kHz (or the frequency response for the rated power output) and a manufacturer selected and stated THD.

http://ecfr.gpoaccess.gov/cgi/t/tex...;view=text;node=16:1.0.1.4.52;idno=16;cc=ecfr


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## informel (Jun 21, 2011)

Generic said:


> Almost all speakers have specs listed. Bose is the only I know that doesn't.
> 
> As far as amps and AVRs go, I do wish their could be some SAE standards or something. Some are under rated, some are over rated. It's a mess.
> 
> Without any standards though, the information on quality equipment is out their. Not really fair to the normal consumer who isn't really in to all of it. On the other hand, it is so easy to do research now days.


I agree that they have some spec for speakers, but spec like:
frequency response 40hz to 22Khz is meaningless, you probably saw those little speaker for computer that have spec like 20hz to 20Khz, we know it is impossible, those spec are probably at -60db


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## GranteedEV (Aug 8, 2010)

informel said:


> Sensivity: in DB/watt/meter (giving sensivity in DB with no reference means nothing)
> frequency response: lower limit - upper limit @ -3DB ex: 40hz - 40Khz @-3DB
> maybe the radiation patern, but I am not sure this would be use by a lot of people


Sensitivity should be given in db/V/m because watts change with respect to frequency. 2.83v/m is the general standard as it translates to 1w @ 8 ohm and 2w @ 4 ohm.

Frequency response lower/upper limits are mostly meaningless because they're affected strongly by things like room influence, our own ear's hearing transfer function, and +/-3db is a very wide, 6db window with lots of room for coloration. I'd prefer something closer to showing that a speaker is +/- 2db or better between 200hz - 10khz. An actual, high resolution graph is prefered to just a one-line specification as this will also indicate if/where the speaker starts to roll off. Remember though, a graph given at 75db may not represent the speaker's response at 90db. Thus there is also a strong need for a power compression information. Even if a speaker is perfectly flat to 20hz that doesn't mean it meaningfully reproduce 20hz.

Speakers should also be specified not only with their axial frequency response (which can be just a matter of passive equalization) but also their radiated frequency response into various directions (20 degrees vertically, 15/30/45/60/75 degrees horizontally) as this more closely represents the speakers consistency as far as what we actually hear in the far field (a combination of direct and reverberant response). Dr. Floyd Toole also suggests replacing the on axis frequency response itself with "listening window" response - an averaging of the response within 15 degree axes.

Also necessary is complex impedance (Z-chart) with phase angles. Most speakers claiming 8 ohm loads are much more taxing on an amplifier than that suggests.

Finally, I feel any good speaker will have a clean waterfall graph. Waterfall graphs don't separate the best from the rest, but they'll quickly throw out the worst from consideration. Waterfall graphs are just one form of showing decay and there's other valid ones as well.

A few companies that do IMO give great examples of how commercial speaker specifications should be include:

http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=569
http://www.ascendacoustics.com/pages/products/speakers/SRT/srtmeas.html
http://philharmonicaudio.com/philharmonic1.html
http://www.bambergaudio.com/s5tmw_specs_r2.pdf



> amplifier
> power is frequently given for one channel at 1Khz
> I beleive it would be better to have at least the power bandwith ex. 105W from 10hz to 40Khz
> and possibly power all channels driven simultaniously


All Channels driven is useful for a 2 channel amp, but less so for a 7 channel amp because that's not a real world scenario being represented. Thus I am most interested in output at low impedances into 2 channel loads - the Power Cube. 

ACD does help us see power supply robustness, but can also be irrelevant in the grand scheme of things. When do you drive all seven channels to full power?

The other important measurement for an amplfiier is its FFT Distortion spectrum @ < 1w where it will spend most of its power.


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## MikeBiker (Jan 3, 2010)

GranteedEV said:


> A few companies that do IMO give great examples of how commercial speaker specifications should be include:
> 
> http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=569
> http://www.ascendacoustics.com/pages/products/speakers/SRT/srtmeas.html
> ...


One of the reasons that I bought Ascend Acoustics speakers was the ample data that their web site provided.


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## ru4au (Dec 7, 2011)

Its all about marketing its not actually what the rating is its how many Sheep can you make drink from the sand....It should be simple this many watts this frequency range at all channels driven.....period....But here is the reality of it Company A: Our receiver named the One has this much power Company B: Well we will call our receiver the One and Only and it has the same amount of power. Customer: Hmmmmmm do I want the one or do I want the One and Only wow how could i not go with the One and only it just has got to be wonderful...Sheep lead to the Oasis to drink...Result: Massive sales of the Bose cubes


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## WooferHound (Dec 8, 2010)

The problem with amplifier ratings has been going on since I can remember in the mid 60's (yes that makes me old). I even remember at some point in the 70's where there was a law passed to require the ratings be stated in RMS power, at which bandwidth, and at what distortion. For about 5 years there was fairly good compliance with this law. But that was 35 years ago and the manufacturers have gradually gotten back to their old ways. The better brands will be quite accurate in their ratings (not always) but the lesser competition has gotten where they will cheat to try and make a sale.

The thing you are wanting with accurate amplifier ratings is the law already, but how are you going to enforce it ?

The biggest problem is with consumer grade gear. Most professional stuff can be trusted.


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## MikeBiker (Jan 3, 2010)

WooferHound said:


> The problem with amplifier ratings has been going on since I can remember in the mid 60's (yes that makes me old). I even remember at some point in the 70's where there was a law passed to require the ratings be stated in RMS power, at which bandwidth, and at what distortion. For about 5 years there was fairly good compliance with this law. But that was 35 years ago and the manufacturers have gradually gotten back to their old ways. The better brands will be quite accurate in their ratings (not always) but the lesser competition has gotten where they will cheat to try and make a sale.
> 
> The thing you are wanting with accurate amplifier ratings is the law already, but how are you going to enforce it ?
> 
> The biggest problem is with consumer grade gear. Most professional stuff can be trusted.


I believe that that was not a law, but an FTC regulation. As it is no longer enforced, I believe that the regulation has been rescinded. All the 500+ watt HTIBs make a joke of power ratings. 

In looking through my AV Receiver manual, I find that the FTC does have some rating specs, but they must be optional. The manual says:

Rated Output Power All Channels: 
110 watts minimum continuous power per channel, 8 ohm loads, 2 channels driven from 20 Hz to 20 kHz, with a maximum total harmonic distortions or 0.08% (FTC)
130 watts minimum continuous power per channel, 6 ohms loads, 2 channels driven at 1 kHz, with a maximum total harmonic distortion of 0.1% (FTC)
120 watts minimum continuous power per channel, 8 ohm loads, 2 channels driven at 1 kHz, with a maximum total harmonic distortion of 0.7% (FTC)
7 ch x 170 W at 6 ohms, 1 kHz, 1 ch driven of 1% (IEC)

If I was the marketing manager, I'd advertise the 1190 watts IEC number, or better still, some bogus 'peak power' that would be more like 10,000 watts!


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## tonyvdb (Sep 5, 2007)

Receiver specifications are all over the board. Most manufacturers only rate the power output 2 channels driven not all 7 or 9. This is where receivers generally fail poorly usually only outputting half of what they are rated to do. I think this is very misleading to the un aware.


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## informel (Jun 21, 2011)

GranteedEV said:


> Sensitivity should be given in db/V/m because watts change with respect to frequency. 2.83v/m is the general standard as it translates to 1w @ 8 ohm and 2w @ 4 ohm.


OK, you are right, speaker are not a pure resistance



GranteedEV said:


> Also necessary is complex impedance (Z-chart) with phase angles.


Wow, a Z-chart, you have just lost 99% of the population (except on this site of course where peoples are very knowledgeable.



GranteedEV said:


> Finally, I feel any good speaker will have a clean waterfall graph.


I know what a Z-chart is because I studied electronic(it would probably take me a while to figure it out as I have been away from the field for quite some time), but I am not sure about the usefulness of waterfall in an anechoic chamber. I thought it was use more to check the acoustic in a particular room (don't flame me if I am totally wrong, I am not an expert in speaker)




GranteedEV said:


> ACD does help us see power supply robustness, but can also be irrelevant in the grand scheme of things. When do you drive all seven channels to full power?


Never, but this could be a good indication of the power supply and amp robustness.


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## informel (Jun 21, 2011)

GranteedEV said:


> http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=569
> http://www.ascendacoustics.com/pages/products/speakers/SRT/srtmeas.html
> http://philharmonicaudio.com/philharmonic1.html
> http://www.bambergaudio.com/s5tmw_specs_r2.pdf


Very nice list, the last one look very expensive, I was surprise of the price of Philharmonic Audio


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## GranteedEV (Aug 8, 2010)

Hi. 



> Wow, a Z-chart, you have just lost 99% of the population (except on this site of course where peoples are very knowledgeable.


Hi. You're right in that a Z-chart might not be immediately comprehensible (mostly because of phase angles) but it helps consumers make educated purchases. For example, you don't need to know a world about electronics or chart-reading to see this so-called 8 ohm nominal speaker:










Is not as easy a load as this so-called 8 ohm nominal speaker:










Of course, if you can analyze the effect of the phase angles, and recognize which frequencies most content you listen to/watch has its power demands centered on, you can get some idea that speaker A might need a more robust amp than speaker B assuming their sensitivity is the same. And if you can't, it doesn't hurt for the information to be there so that someone who can, can point it out and help that person out. :T





> but I am not sure about the usefulness of waterfall in an anechoic chamber. I thought it was use more to check the acoustic in a particular room


waterfalls show what's going on as time elapse - the decay of the signal. Now a really long gated waterfall shows the decay of the room. But a short gated impulse response/water fall can still show a lot of information about problems with speakers. Floyd Toole does argue that they're "cosmetic" and I agree - good/mediocre speakers will have sufficiently good waterfalls - but poor speakers certainly won't. 

Observe a speaker with little if any aberation:










and a $5000 audiophile speaker that isn't behaving pistonically










Now frequency response plots alone will normally tell your a lot of what you need to know, but I like CSD/waterfalls.



> (don't flame me if I am totally wrong, I am not an expert in speaker)


No flaming here :T



> Never, but this could be a good indication of the power supply and amp robustness.


could be, or it could be an indication of an amp with discrete power supplies to each of its amplifier channels - and thus actually lacking headroom in real world conditions dollar-for-dollar. I'm not against measuring ACD, but I'm against emphasizing it over 2CD into various loads. If a receiver can do about 60% into 7ch, 80% inch 5ch @ 1% distortion of its rated power, I think that's more than enough.


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## soup3184 (Nov 7, 2010)

WooferHound said:


> The problem with amplifier ratings has been going on since I can remember in the mid 60's (yes that makes me old). I even remember at some point in the 70's where there was a law passed to require the ratings be stated in RMS power, at which bandwidth, and at what distortion. For about 5 years there was fairly good compliance with this law. But that was 35 years ago and the manufacturers have gradually gotten back to their old ways. The better brands will be quite accurate in their ratings (not always) but the lesser competition has gotten where they will cheat to try and make a sale.
> 
> The thing you are wanting with accurate amplifier ratings is the law already, but how are you going to enforce it ?
> 
> The biggest problem is with consumer grade gear. Most professional stuff can be trusted.


I remember that so well. I used that info to buy my first integrated amp in 1975. I wish they had stuck to those standards. I think they should bring them back.


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## informel (Jun 21, 2011)

soup3184 said:


> I remember that so well. I used that info to buy my first integrated amp in 1975. I wish they had stuck to those standards. I think they should bring them back.


agree


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## gdstupak (Jul 13, 2010)

For the majority of people that don't care to look at all the graphs or don't care to understand them, I like the THX certification system. There are several levels of certification that let you know that certain equipment will be able to play reference levels in certain size rooms at certain listening distances.

http://www.thx.com/consumer/home-en...ter/thx-certification-performance-categories/

http://www.thx.com/consumer/thx-technology/thx-reference-level/


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## audioengineer (Feb 8, 2012)

Waterfalls are not of any real utility to the vast majority of people. Rather, I believe they mislead because of people's tendency to believe they can hear with their eyes better than is actually possible. 

There are many reasons. Example: the waterfall shows you something about the energy storage of a system, but it says nothing about the audible threshold as a function of level/time/frequency. So, how do you know which features in a waterfall are audible and which are not? Second, this is the response to an instantaneous hard gate of a signal with uniform energy across the entire spectrum. Very few pieces of music will contain anything like this (I've yet to find music that has a single area that looks like this). Therefore, even if it did represent what you can and cannot hear, it's unrealistic. Third, another poster mentions that most of this goes out the window in a real, non-anechoic environment. In most cases, the room will have much more reverberation and room energy will mask this the stuff you see in such a waterfall. Yes, if there is an obvious storage of energy at some narrow frequency and the decay is really slow it might be noticable on a hard gated sound, but we've already mentioned that this doesn't occur in the vast vast majority of music. 

Radiation patterns: these are a little more useful if they're averaged over sufficient angle, but still the character of the room and speaker to listener transfer function is going to make a very big contribution to the sound. If you have these directional transfer functions, you can make some sort of prediction of the speaker to ear behavior. But, does that mean you know what it's going to sound like? 

Finally, let's not forget that most of the music we listen to is stereo (meaning content coming out of both speakers). For this stuff, the interaction of the two speakers in the listening environment is far more important than almost any spec I've ever seen in any manufacturers literature or audio review (including John Atkinson's admirable tests). The ability for a stereo pair to convey a highly coherent sound to each of your ears is going to have a substantial effect on the quality of the phantom imaging (other than hard left/right, it's phantom guys). So, if you want a meaningful spec, let's get a "stereo" frequency response to each of your ears as a function of left-right channel differences. That means as a function of magnitude pan, as a function of delay pan, and as a function of time (early, mid, late). But, as mentioned by previous posters, that will leave 99.99% of the audio buying public in the dust.

So, are companies like Bose so evil to dispense with piles of specs which ultimately tell you nothing about how it will sound in your own home? Bose at least tells you to take it home and live with it for a while. If you don't like it you can take it back for a full refund. Ditto any really good high-end audio emporium. I've never bought a piece of audio gear (and I have some near nose bleed stuff) without a home audition period.... Or do you prefer those companies that pile on spec after meaningless spec in an attempt to convince you that you can hear those good numbers?

Audioengineer


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## lcaillo (May 2, 2006)

Your points are certainly valid, up to a point, but I don't see an alternative suggestion that justifies the design nor documents the performance of Bose or other products in your post. Is engineering really all about "take it home and try it?" 

Audio performance is complex. Specifications and measurements have to be taken in context. Most of the discussion of waterfalls that you will see here relate to performance in a particular room that a user is trying to optimize. 

I am not sure what your agenda is here but if you are attempting to justify Bose products by criticizing the use of specifications and measurements, I don't find your perspective very convincing. Most here who have opininions on Bose don't base them upon measurements but upon listening. I would welcome more objective assessments that would be meaningful. Do you have suggestions?


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## Mike P. (Apr 6, 2007)

> So, are companies like Bose so evil to dispense with piles of specs which ultimately tell you nothing about how it will sound in your own home?


No, Bose isn't evil, they are actually pretty smart with their marketing. There are no specs listed for the Acoustimass 10 Speaker System, it costs $1000, the Bose website says:

_*Our best 5.1-channel home theater speaker system for large rooms*_

_*Powered Acoustimass module adds drama to music and movies. Downward-firing drivers and proprietary technology deliver the lowest audible notes and effects with clarity and balance.

*_Ever heard one? I have_*. *_My sister bought one a month ago.Two 5.5 inch drivers that can't do 35 hz let alone _*the lowest audible notes and effects. *_A great system for the uneducated and uniformed. Let your ears be the judge.

​


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## audioengineer (Feb 8, 2012)

lcaillo said:


> (snip) Do you have suggestions?


You've made some excellent points. Engineering is NOT just about taking it home and listening to it. Engineers need to figure out how to measure the things that matter so they can produce better designs in an intelligent manner. FWIW, I'm not saying a purely empirical approach is not intelligent (e.g. trial and error). Unfortunately, most of the good engineering on the issue of why speakers sound the way they do will likely never make it into print because companies consider it IP. Practically everything Ffloyd and Sean (Olive) write about audio is valuable, if you understand the assumptions and caveats. A good place to start if you want to learn more on why traditional frequency response measurements and information are near useless and what you might do instead is Lipshitz and Vanderkooys 1985 paper on "Experiments in Direct/Reverberant Ratio Modification." One take away is that you can't design for a target frequency response and expect to know what it'll really sound like without taking radiation pattern into account. By extension, you also need the room acoustics. 

This is just the tip of the iceberg though (nearly 30 years ago...).

GDSTUPAK: I agree with you that Tom's THX work was a real benefit to consumers because it says, "trust our judgement that systems which meet our requirements should be capable of providing some minimum level of audio reproduction quality." That gets the consumer away from meaningless or hard to understand specs. I don't think THX is enough to distinguish between good and really good, but it'll certainly separate the wheat from the chaff. 

Mike P: I've tested a fair amount of audio gear in my life. I'm not saying your sister's Bose system could reproduce 35Hz, but it's not necessarily the system's fault. I remember an incident where a friend of mine bought a fairly capable home theater system and was showing it off to me. First thing I noticed is that his amp was clipping on bass heavy material yet it wasn't playing that loud. A simple reciprocal "walk-around" revealed he'd put is subwoofer in a spot where there was a intensely deep room null in the lower midbass range (I think it was something like 70Hz). His receivers autoEQ function had put a huge EQ peak there and it was clipping when trying to drive +15dB of power into that frequency. He needed a 2000watt amp rather than a 100watt amp. We moved the sub, to a better spot and now his system can shake the house across the whole bass range. Someone might have said, brand X subs suck big time, but that is not necessarily so. 

And ... I don't think you are being rational to suggest that low frequency response is limited due to the fact that there are only two 5.5" drivers in that box. It really depends on the box, and specifics of the driver design. Bose uses ported boxes and waveguides. If the port or waveguide is tuned at 35Hz, a 2" woofer with the right performance characteristics could drive that port/guide to produce a fair amount of output at 35Hz. This is a case of not judging a book by the cover. We don't hear with our eyes. They just bias our opinions. I've been thru a Bose store demo, and in that setup their system had plenty of low frequency output. Nothing close to my main system at home (The Bose felt like it was around 15dB lower in maximum output), but it did play fairly deep. 

In summary: if a sub sucks, make sure it's not the room or sub placement. If you think there's no 35Hz output, it's easily confirmed with a slow sine sweep on a CD/DVD and a cheap SPL meter.


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## audioengineer (Feb 8, 2012)

lcaillo said:


> I am not sure what your agenda is here but if you are attempting to justify Bose products by criticizing the use of specifications and measurements, I don't find your perspective very convincing. Most here who have opininions on Bose don't base them upon measurements but upon listening. I would welcome more objective assessments that would be meaningful. Do you have suggestions?



BTW, I'm not going to argue preference. I know too many people who think highly coloured sound is audiophile performance. I've been into many super high end shops where the $10k speaker demo is done with one speaker wired out of phase or the wrong left and right speaker matched up (really happens). 

I'm am ABSOLUTELY justifying Bose's lack of numerical audio performance specifications. I am ABSOLUTELY saying that unless you actually understand audio engineering you should stick with subjective evaluations to judge audio performance. I absolutely would welcome better objective measurements that tell us what components sound like (that's part of my job, FWIW). But, most of you wouldn't understand these measurements and I don't think I'm allowed to post them anyway because they're the property of my employer

Finally, most of the people I personally know who bash Bose (1) don't bother to listen to it, (2) prefer highly exaggerated sound (etched treble clarity comes to mind), or (3) think everyone else in the world should adopt their equation for cost/performance. I do not use Bose for my serious audio system at home, but I do use a variety of Bose products (past cars I've owned), Sound Dock Portable, noise cancelling headphones (travel only).


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## gdstupak (Jul 13, 2010)

audioengineer said:


> ... I'm not saying your sister's Bose system could reproduce 35Hz, but it's not necessarily the system's fault....
> ... I've been thru a Bose store demo, and in that setup their system had plenty of low frequency output. Nothing close to my main system at home (The Bose felt like it was around 15dB lower in maximum output), but it did play fairly deep...
> ...In summary: if a sub sucks, make sure it's not the room or sub placement. If you think there's no 35Hz output, it's easily confirmed with a slow sine sweep on a CD/DVD and a cheap SPL meter.


Here is a simple graph I made comparing the SPL measurements of Bose and 2 other speaker sets (no separate sub was used):
http://www.hometheatershack.com/for...1d1297467116-bose-quality-frequency-chart.pdf
Now for the testing details:
--Testing location was my great room, same physical layout that is in my pics.
--All L/R speakers were placed at the exact same spot. Each speaker was 14' from the spl meter.
--The Bose bass module was placed 4.5' from the front wall, 8' from side walls, 10' from the spl meter. It was turned so the port was facing the side wall (module placement had a great effect on the frequency response, although I did not have time to find the best spot).
--All speaker set testing used the same avr set up: no corrections (no Audyssey, no eq), no outboard amp, no outboard eq.
--The main volume for each speaker set was set to 82db at 1Khz.

TEST CD: stereophile Test CD2, tracks 16,17,18. 20hz-20Khz, 1/3 octave, warble tones.
DVD/CD PLAYER: Panasonic DMP-BD35
SPL METER: Craftsman Analog 82297, C weighting, slow.
AVR: Onkyo TX-SR706

SPEAKER SETS: 
(1) Bose AM5 (circa 1995)
(2) JBL Studio S312, 12" tower (circa 2003)
(3) DCM KX12 II, 12" tower (circa 1998)
==================================================================
This test has been performed in more than 4 completely different locations and have always come out with similar results.
For the measurements I placed the Bose bass module (notice I didn't call it a subwoofer) out away from the walls to get a better reading of the speaker itself, placing the bass module closer to the walls boosted the bass significantly.
A note on listening tests vs. SPL measurement tests: It's always surprised me to see that the JBL's SPL's drop off the fastest above 2k hz. When listening to the different speaker set's I would definitely describe the JBL's as having accentuated highs, and the Bose I would have said to have the least amount of energy up high. Completely opposite listening results from what I would have expected when looking at the measured frequency response.
This isn't a Bose review thread so I'll stop here.


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## Mike P. (Apr 6, 2007)

> And ... I don't think you are being rational to suggest that low frequency response is limited due to the fact that there are only two 5.5" drivers in that box. It really depends on the box, and specifics of the driver design. Bose uses ported boxes and waveguides. If the port or waveguide is tuned at 35Hz, a 2" woofer with the right performance characteristics could drive that port/guide to produce a fair amount of output at 35Hz.


This isn't about 35 hz, it's about Bose's system _for *large rooms* that deliver the* lowest audible notes and effects.*_

Calibrated SPL testing from the listening position will be posted next week when I get home from work. Since the lowest audible notes and effects means 20 hz extension in the majority of action movies we'll see exactly what kind of output the Acoustimass can provide.


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## audioengineer (Feb 8, 2012)

Mike P. said:


> This isn't about 35 hz, it's about Bose's system _for *large rooms* that deliver the* lowest audible notes and effects.*_
> 
> Calibrated SPL testing from the listening position will be posted next week when I get home from work. Since the lowest audible notes and effects means 20 hz extension in the majority of action movies we'll see exactly what kind of output the Acoustimass can provide.



Marketing .... most adults and intelligent children understand that marketing, in general, is to be taken with a grain of salt ;-) Shall we talk about the marketing claims of all audio companies to see who's not guilty?

Audible? You can hear down to 20Hz, and feel down to 0Hz. At the other end, 15kHz is a good limit for old folks and somewhere between that and 20kHz is fine for everyone else 

I am not aware of many subs that have substantial output down to 20Hz. My L/R mains only go down to 27Hz, but at least they have plenty of SPL (room gain helps a bit). I personally don't miss those last 7 hz, and for anything other than the big smashem up stuff, I could live with a lower limit in the low thirties.


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## lcaillo (May 2, 2006)

I don't think anyone here will dispute the notion that published response specs tell you much about a speaker's sound. Justifying Bose or any other product based upon their refusal to provide such is of little value, however. 

As I said most of the people on this forum who have concluded that Bose is a poor value in most products have come to that view based upon listening comparisons or measurements in actual listening settings, not out of context specs.

We do not allow bashing of any vendor, including Bose. The fact that the overwhelming majority of the users here have similar conclusions regarding the brand speaks for itself. The typical user here is not your average consumer. Most are quite familiar with many products and many actually build their own and pay great attention to room response.

Anyone who feels that there is a case to be made for a Bose product is welcome to make it. I have yet to see s convincing opinion or set of facts that support any of their speakers as being a very appealing value relative to the rest of the market.


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## audioengineer (Feb 8, 2012)

gdstupak said:


> Here is a simple graph I made comparing the SPL measurements of Bose and 2 other speaker sets (no separate sub was used):


I think it's cool that someone here does measurements and tries to figure out what works and what doesn't.
Let me state a generality, which are always not completely true. When you put a low frequency source away from a wall, you will often cause a problem with 1/2wave cancellation. If you put it away from a wall, the energy going toward the wall reflects (part of it) and if that reflected energy arrives back at that low frequency source out of phase (180deg, half a wavelength) then it'll affect the output of the source. At 8ft spacing you might be inducing a bass bump or dip. That's why it's generally recommended to put low frequency sources along room boundaries (the more the better) and then taming excess energy with some gentle EQ. That doesn't solve all problems, which is why some people get an improvement going to 2 LF sources. This is a drawback of my L/R mains. They play low enough that the ideal placement for <80Hz is not the same as for the midrange. If I had to do it over again, I'd get a LF+sat system where the mains only play down to 50 or 60Hz.


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## audioengineer (Feb 8, 2012)

lcaillo said:


> I don't think anyone here will dispute the notion that published response specs tell you much about a speaker's sound. Justifying Bose or any other product based upon their refusal to provide such is of little value, however.
> 
> As I said most of the people on this forum who have concluded that Bose is a poor value in most products have come to that view based upon listening comparisons or measurements in actual listening settings, not out of context specs.
> 
> We do not allow bashing of any vendor, including Bose.


you haven't given an iota of rational support for the idea that giving out generally misunderstood specs is better than nothing at all. It's exactly my contention that this is a disservice by audio companies that want to bias you with ads rather than their audible performance.

Bashing: there's lots of vendor bashing on this forum, albeit better than elsewhere. I'll do my best to adhere to the policy. Time will tell if I can stay above the fray.

I also don't believe in arguing value. I have a friend who spent nearly 5 figures restoring a little part for a car that nobody will ever see. Was that good value, sure based on his personal goals. Value is so multi-dimensional and so personal. Every product I think is a good value, will be the opposite for someone else. Do any of you drink $50 a bottle wine or in contrast $12/bottle (isn't life too short for that?)? 

Most of you here would probably consider my HT mains to be a poor value, but think my rears are too inexpensive to be any good. But, they work for me and I won't use my choices to judge anyone elses.


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## gdstupak (Jul 13, 2010)

lcaillo said:


> We do not allow bashing of any vendor, including Bose. The fact that the overwhelming majority of the users here have similar conclusions regarding the brand speaks for itself.


It's not as bad as on other sites, but close. Much of the misinformation on the Bose speakers here is just regurgitated misinformation from another famous Bose bashing site.
(Most of this concerns the Acoustimass sytem with the cube sats)
-poor quality paper drivers
-the sats drivers and enclosures are too small to produce room filling sound
-one note bass sound
-the bass module ignores anything below 40hz
-the sats won't play above 12khz
-the sats don't play lower than 300hz
-there is a huge hole ("chunk") of sound missing between the bass module and sats (This has been "proven" with a graph that shows a 5db dip where the bass module meets the sats. I'm surprised people on this forum agree with the analysis of this graph, it shows they don't know how to read a graph. For this particular graph, the speakers were measured independent of each other, so for proper cohesion between the bass and sats there needs to be a dip. When the bass and sats are measured together, the dip goes away and the freq response is acceptable, well, I've seen worse anyway.)

If you have experimented with listening to Bose in your home and still don't like the sound, fine and dandy. But please stop perpetuating lies.

I agree with many on here that don't like the marketing terminology used by Bose. My old Accoustimass system uses a passive 'bass module' that I used to couple with a true sub to get those proper lows. Now they use an active 'subwoofer' that I wouldn't consider a true subwoofer. And I don't consider their sound quality to be high fidelity with great detail, but when set up properly the old AM5's do sound good.


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## Mike P. (Apr 6, 2007)

> you haven't given an iota of rational support for the idea that giving out generally misunderstood specs is better than nothing at all.



Look up any make and model listed to see what the manufacturer states, then check the specific test result to see how the sub performed. (disregard the DIY entries)

http://www.hometheatershack.com/for...index-subwoofer-tests-manufacturer-model.html

Since you're not aware of many subs that have substantial output down to 20Hz, this second link should help you with that.

http://www.data-bass.com/systems


 
​

​


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## audioengineer (Feb 8, 2012)

Mike P. said:


> Look up any make and model listed to see what the manufacturer states, then check the specific test result to see how the sub performed. (disregard the DIY entries)
> 
> http://www.hometheatershack.com/for...index-subwoofer-tests-manufacturer-model.html
> 
> ...


Do you consider -20dB to be "substantial" output?

Anyway: 

Genelec 7050B is -20dB at 20Hz. How much does that one cost? Oh, it's only a grand. That's a good value.

Hsu MBM-12: one of my favorite subwoofer companies (performance and value). Down over 25dB at 20Hz

REL R-305: that's a good one, and the $1500 is cheap

Velodyne SPL_1200: down 15dB at 20Hz. Not bad. Always thought this was a standup company

B&W ASW620: down 20dB at 20Hz, but we all know that's a brand


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## audioengineer (Feb 8, 2012)

Mike P,
FWIW these measurements are of value as a form of relative comparison. But it still doesn't tell you how they will perform in a particular environment. So, you've shown one iota. Excellent. This is why I'm here and not in avsf*r*m.com

We're fortunate that most credible speaker companies have finally accepted the value of room specific EQ. It only took 30 years for that to happen (exceptions being companies like Meridian, TAD Electroakustiks, Bose, the nice fellow that runs Tact audio, etc.). BTW, I'm not saying these examples of companies that were early adopters of room based EQ are comparable in any regard other than their recognition that the room is a huge factor in audio quality. 

Interesting to note that Floyd and others proved this many decades ago yet the audiophile industry was arguably the last to acknowledge and then do something about it.


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## tonyvdb (Sep 5, 2007)

audioengineer said:


> I am not aware of many subs that have substantial output down to 20Hz.


SVS PB13Ultra for example does very well at 20Hz even down to 15Hz at good SPL I own one and many member here own them as well and can attest to its ability.
There are many manufacturers of subs that do go below 20Hz with good output.


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> Waterfalls are not of any real utility to the vast majority of people. Rather, I believe they mislead because of people's tendency to believe they can hear with their eyes better than is actually possible.


Being able to correlate measurements to audibility is certainly important - as true for electronics as it is for transducers. However waterfalls can show clear issues without overanalysis. Why one would choose to reject it is beyond me, though i'll agree that there's other methods of getting the same information.



> There are many reasons. Example: the waterfall shows you something about the energy storage of a system, but it says nothing about the audible threshold as a function of level/time/frequency. So, how do you know which features in a waterfall are audible and which are not?


It takes experience and judgement, but I can recognize something like, for example, a driver's metal cone breakup in a waterfall immediately. As for its audibility, it's safe engineering practice to get these types of things 24 to 40db down in level. Whether it's audible or not is tertiary - the goal of the specification is to show careful design.



> Second, this is the response to an instantaneous hard gate of a signal with uniform energy across the entire spectrum. Very few pieces of music will contain anything like this (I've yet to find music that has a single area that looks like this). Therefore, even if it did represent what you can and cannot hear, it's unrealistic.


I'd beg to differ. Speakers respond to an input. Unlike with electronics, with transducers the nature of the input is less relevant than the ability of the speaker to reproduce it. It's true that music is more complex than test signals - which is exactly why a speaker that struggles with test signals will be at even more of a loss than a speaker which does not, when playing back real content. 



> In most cases, the room will have much more reverberation and room energy will mask this the stuff you see in such a waterfall.


I disagree. I'm one of the biggest proponents of the concept that the room and its interaction with the speaker are a dominant factor in what we hear. But resonances are audible; and it depends on their Q and their damping. It's nonsense to consider a resonant, undamped loudspeaker to be high fidelity because it's adding its own signature to the sound. What the room adds is tertiary and delayed in time. What the speaker adds will affect timbre, resolution, etc. Now yes, most loudspeakers will have some resonances here and there - it's the nature of any product where cost is an object. The reality is though, well engineered products will measure well. 



> Radiation patterns: these are a little more useful if they're averaged over sufficient angle, but still the character of the room and speaker to listener transfer function is going to make a very big contribution to the sound.


 The reality is that it's the first 5ms, maybe 10ms of what we hear that contributes to timbre perception, and the first 10-15ms that contribute to imaging. The character of the room will still affect the reflected sound, but because of how our brains hear, it will mostly affect our perception of "soundstage" / spaciousness. The reality is that you can very accurately predict a the sound of a speaker based on its measurable behaviour with respect to polar response.



> But, does that mean you know what it's going to sound like?


A speaker with controlled, uniform radiation pattern and flat frequency response will more or less sound like the source content. Sure there will be differences as there's no perfect speaker but speakers with controlled on and off-axis response sound more similar than not.



> . The ability for a stereo pair to convey a highly coherent sound to each of your ears is going to have a substantial effect on the quality of the phantom imaging (other than hard left/right, it's phantom guys). So, if you want a meaningful spec, let's get a "stereo" frequency response to each of your ears as a function of left-right channel differences.


As far as coherency is concerned, it's not a stereo effect. Coherency is best described as "mono imaging" and best described as phase-difference in the crossover region.



> So, are companies like Bose so evil to dispense with piles of specs which ultimately tell you nothing about how it will sound in your own home?


Most certainly, because those specs will ultimately tell you 90% of how it will sound in your own home. In Bose' case, it's "extremely inaccurate". Now it's true that not everyone prefers accuracy, mostly because most people are not used to anything but the stock stereo in their car. Olive/Toole's research even shows that almost invariably, once biases are removed, people prefer more measurably accurate systems, though.

That's why when you look at the spec sheet:

http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=569

You get _meaningful information_ as it pertains to that speaker's accuracy. 




> Bose at least tells you to take it home and live with it for a while. If you don't like it you can take it back for a full refund.


The question is whom is living with it for a while. Just being a step up from "incredibly poor" does not imply a product is not itself, very poor, especially when dollars become a factor.

The reality with Bose is simple: "it's not as harsh as a telephone speaker/stock car stereo/built-in TV speaker/cheap logitech PC speaker, therefore it's world class."

And the truth is, most people don't bother to think about the above reality critically.



> Or do you prefer those companies that pile on spec after meaningless spec in an attempt to convince you that you can hear those good numbers?


The point of good numbers isn't _to_ hear them. It's to _not hear them_. So yes, I prefer companies that engineer products with a goal of fidelity, as evidenced by the measurements. That's why I would gravitate towards brands like KEF, Revel, TAD, Philharmonic, Gedlee, etc. They're ultimately more similar speakers than they are different, with good reason - because they strive for accuracy. What differences exist, are minor and often boil down to preference or budget or aesthetics. But the similarities that exist are obvious. You can hear the similarities with your ears. Subjectively.



> I've been thru a Bose store demo, and in that setup their system had plenty of low frequency output


All of the Bose demos I heard, were obnoxiously heavy in the mid/upper bass department without a hint of depth, though I can certainly see untrained listeners being fooled by it. The reality with these Bose demoes is that they're dinosaur stomps and gunfire. How one can evaluate a reproduction device from artificial sounds is beyond me.


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## Mike P. (Apr 6, 2007)

audioengineer said:


> Do you consider -20dB to be "substantial" output?
> 
> Anyway:
> 
> ...


It appears you misunderstood. These manufacturers state the frequency response of their products which you stated are "generally misunderstood specs".

In the case of the Genelec 7050B they advertise a Free field frequency response 25-85 Hz. It measured *+/- 3 dB points: 25 Hz - 135 Hz*
The Hsu MBM-12 is advertised to have a frequency response of 50-150 Hz +/- 2 db, it measured *+/- 3 db points 43.5 hz ->200 hz.*

The REL R-305 is advertised to have a frequency response of 25Hz-100Hz, it measured *+/- 3 dB points: 23 Hz - 80 Hz.

*I could go on. Clearly these subs were not designed for 20 hz extension and they clearly don't advertise that they do. And not one of them advertise that they provide the _* lowest audible notes and effects.*_

I do agree with your statement that advertising claims should be taken with a grain of salt, but there's a big difference between bending the truth a little and deceptive marketing practices. Just my opinion.

​ 

 

​​

​


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## audioengineer (Feb 8, 2012)

GranteedEV said:


> Being able to correlate measurements to audibility is certainly important - as true for electronics as it is for transducers. However waterfalls can show clear issues without overanalysis. Why one would choose to reject it is beyond me, though i'll agree that there's other methods of getting the same information.
> 
> 
> 
> ...



GranteedEV,
Nice post, sorry about the semi-troll. On most of this I'm not 180 deg ... maybe 85 degrees apart from you. So, let's start by not arguing the excluded middle (I was guilty in the last post).



GranteedEV said:


> Being able to correlate measurements to audibility is certainly important - as true for electronics as it is for transducers. However waterfalls can show clear issues without overanalysis. Why one would choose to reject it is beyond me, though i'll agree that there's other methods of getting the same information.


Okay, let's not reject the waterfall plot completely. It's real data, subject to the analysis method. First point about waterfalls. How do you know what you can and cannot hear? If you don't then you can't relate the objective to the subjective. Being able to correlate to audibility is nearly EVERYTHING (sorry but I meant to all-cap).



GranteedEV said:


> waterfalls can show clear issues without overanalysis ....


Yes, you can learn a lot from a waterfall. It is one nice way to show where a system stores energy (ala resonates). Yes, you are right that ideally we don't want any resonances in the system. Practically speaking, that will require a substantial number of other compromises to achieve. Materials that are very damped tend also not to be very stiff and light. That's why speaker designers use a variety of FOM's that characterize the tradeoff between weight, damping, stiffness. Read any of the many public domain articles by professional speaker designers (the individual driver, not the driver in the box). Notice how they like to refer to the speed of sound in the material? Anyway, if you can afford the tradeoffs, you can design for less resonant behavior and that is a good thing. As soon as things like cost, efficiency, bandwidth, excursion and other tradeoffs come into the picture, then sometimes you may find that it's okay to have a few resonances ... because ... they ... aren't ... audible ... Now we've come full circle, yes?

Have mega bucks and unlimited watts, space? Go for that 100% non-resonant system (arguing to the extreme). Designing a product that you have to sell to a few hundred people at a profit? Isn't that called engineering.

So, what features in a waterfall are audible? Hard to say because everyone hears differently. But we can say something about it in a statistical sense. Try Fletchers book on human hearing.




GranteedEV said:


> waterfalls can show clear issues without overanalysis .... As for its audibility, it's safe engineering practice to get these types of things 24 to 40db down in level. Whether it's audible or not is tertiary - the goal of the specification is to show careful design ...


Okay, we're getting closer to pi radians apart. When you say 24dB or further down, that depends on when. The human hearing system integrates when sensing loudness and it also remembers (stores energy). That means the hearing system resonances can mask resonances in the acoustic output of a device. A good engineering design might choose to exploit that fact and let some inaudible or nearly inaudible resonances go so design time and budget can be directed toward other more serious issues. And ... tell me again why audibility is tertiary!?!?! I generally don't design things for microphones but for humans. If someone wants to pay be big money and ignores what I tell them, I suppose I might be willing to design for a Gras microphone.



GranteedEV said:


> But resonances are audible; and it depends on their Q and their damping. It's nonsense to consider a resonant, undamped loudspeaker to be high fidelity


I didn't say any amount of resonance is okay. I just said inaudible resonances are okay. And if you can't apply a scale of audibility to a waterfall, all but the most egregious resonances you see are ambiguous. So, what do you consider undamped? What do you consider highly resonant? How about when Q is 0.708? How about 0.709? How about 0.823? How about ... cover the kids ears ... a Qts of 1.0!! Wow, that sure is undamped!

Have you ever designed a loudspeaker, and varied Qts (while holding everything else constant) ... and the listened to the audiblity of Q? If not, how do you set the threshold for what is acceptable and unacceptable damping? I'm not saying damping isn't important. It IS important, but unless you're building a product to make a microphone happy, you should understand and apply some audibility criteria (with some safety margin). 

BTW, have you every heard a high fidelity speaker that uses a passive radiator or vented LF enclosure? How about a horn? Those are intrinsically resonant structures. Also, rooms are resonant too. Does it matter if the rooms resonaces are 10x or 100x worse that the speakers at a given frequency? It does matter because rooms can and often do mask all manner of speaker design evils. FWIW, John Atkinson has some pretty interesting things to say in his AES papers on objective measurements of loudspeaker systems.

Nuff for now. I'm a pretty fast on the keyboard, but your interesting/intelligent response deserve more time than I have right now. I promise to get back to this post later. I agree with a number of things you say later in your post.


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## audioengineer (Feb 8, 2012)

Yes, I did misread your post. Like I said, those are all good subs. The specs are useful to the extent that they give you some sense of what the potential of these subs might be in your room. But, as I first said, the specs don't tell you what you will get in your room. I am in 100% agreement that if a sub's 2pi response is good down to 25Hz -3dB, there will be some combination of room placement and listener position that should yield output at 25Hz that's within 3dB of some other point in frequency above 25Hz. It's possible that a room mode will yield a -3dB point of 20Hz. It's also possible that you'll have bad luck and have a null at 30Hz which greatly reduces the response below 33Hz. Maybe your room has a nasty high Q mode at 70Hz, and you'll think it's the sub that is to blame for the loose and boomy bass. 

So, I'll stop being a bit of a troll and say ... many specifications have some utility when combined with the knowledge to interpret them. Specs commonly used in the audio industry will not tell you 90% how a speaker will sound in your home. They won't tell you the half of it. Maybe a quarter? And yet, I have friends who study data/spec sheets night after night hoping to pic the best speaker or the best amplifier for their dollar. I argue that that same amount of time would be better spent listening to the products in question. Yes, those of you who are competent professionals or exceptional hobbyists will know how to make some sense of some of those specs, but you folks are a very very small minority of the audio buying public. So, I commend any/all audio companies that urge you to use your ears as the final arbiter of what sounds good. I'm not saying any adhoc listening is as good as carefully conducted critical listening sessions where the listener is highly trained. I'm just arguing for the importance of hearing over seeing specs (I'm a bit of a subjectivist).


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> A good engineering design might choose to exploit that fact and let some inaudible or nearly inaudible resonances go so design time and budget can be directed toward other more serious issues.


Absolutely. Cost cutting is definitely important. But Companies like Harman and Pioneer have certainly shown that speakers don't need to measure poorly if they're inexpensive. That means it's NOT an excuse for other companies like Bose.



> And ... tell me again why audibility is tertiary!?!?! I generally don't design things for microphones but for humans. If someone wants to pay be big money and ignores what I tell them, I suppose I might be willing to design for a Gras microphone.


A valid argument, but not one I subscribe to. Here's the deal. A company, let's call them Ackscion Audio, makes a speaker that it thinks is as good as the research gets. It might have what their measurements show is below the threshold of hearing. Flat response, decent power response, decent power handling. Their listening tests show this 1.5k speaker to be similarily good to a $8,000 Paradigm S8.

The measurements, however disagree. Their claim is that all issues are inaudible, and that spending more on more crossover components, better cabinet construction, etc, would not make any improvements.

What do you think? That the extra $6500 in a paradigm S8 is merely fluff and it's impossible to improve up a 1.5k speaker because the tests were inconclusive?



> Have you ever designed a loudspeaker, and varied Qts (while holding everything else constant) ... and the listened to the audiblity of Q? If not, how do you set the threshold for what is acceptable and unacceptable damping? I'm not saying damping isn't important. It IS important, but unless you're building a product to make a microphone happy, you should understand and apply some audibility criteria (with some safety margin).


Right. And we're getting into some fine details. However i want to state that it's not difficult for companies to engineer a speaker with a decent waterfall.

Here's a $100/pr pioneer speaker:










Again, we're talking about specifications - bare minimums. It's safe to say that between 4khz-9khz, that $100 speaker has less resonant behavior than this more expensive speaker:










Is there still a question of audibility? Sure there is. But it just doesn't make sense for the former to have cleaner performance than the latter, especially since the latter evidently can be improved by a crossover mod. The scale on both is 24db so it's apples-to-apples that the less expensive speaker looks cleaner. I know which speaker i'd be more inclined to _want to audition_, all else equal. 

Now as far as crossover points, yes the higher XO point will reduce cost, and also improve tweeter power handling. However the question arises of why use such a difficult woofer to start with, if cost is an issue? Again, it all boils down to questionable decision. Comparitively, an Infinity CMMD driver would probably cost the same, be comparitively stiff, and comparitively dynamic, yet not suffer the massive cone breakup. It all comes back to the same issues of design decisions. We can't all agree, but we at least have the right to decide whether something is worth our time in an audition.



> BTW, have you every heard a high fidelity speaker that uses a passive radiator or vented LF enclosure? How about a horn? Those are intrinsically resonant structures. Also, rooms are resonant too. Does it matter if the rooms resonaces are 10x or 100x worse that the speakers at a given frequency? It does matter because rooms can and often do mask all manner of speaker design evils


The wavelengths involved are totally different. A waterfall of a speaker is more meaningful in the upper midrange and treble, where resonances are offensive.

A _room's masking effect_ does not come in until the shroeder frequency. And yes, speakers can minimize that too - a cardioid for example will NOT interact with a room the same as a typical monopole.

Beyond that, there's still the matter of our hearing. We hear differently at 500hz than we do at 2khz. A resonance at the latter is simply scientifically more offensive than a resonance at the former frequency. Our ear's sensitivity to SPL, sensitivity to group delay, and overall acuteness are just higher at this frequency. So it makes sense for a waterfall to be more meaningful at a frequency where we'll recognize problems with speakers, than at a frequency where not only are we not very receptive of issues, but also happen to be used to the effect of rooms etc in real life.

The reality is, over 80% of speakers fit into the "poor" category, even if they have their fans. The few that don't, almost invariably measure excellently in various ways (or are in a room custom fitted for them) and sound more similar than not. Spec sheets aren't normally adequate, but that doesn't mean measurements aren't.

It makes a lot more sense to weed out poor-measuring speakers and audition the good-measuring speakers, than to audition all speakers and pick the one that impresses you the most. The majority of people are going to be "most impressed" by heightened bass and treble, and demo material that itself is impressive. I don't consider that a true audition. Most true auditions require appointments, and generally require that you drive to some difficult-to-get-to place. It's an investment of time and it only makes sense to make a list first, of speakers that pique your interest. Else everyone would end up with the same oversaturated brands IE Polk, Paradigm, Bose, and B&W whilst auditioning little else. It might not even be their most prefered product - simply what was available to audition at the nearest hi fi shop.

I can think of at least one person who recently hit up best buy, auditioned four-five speakers, and went with a pair of B&W CM9s. Then after some "living with", plus some guidance, ended up returning the CM9s and doing _much_ more thorough research into his purchase, with some serious attention to measurements and actual listening goals. I'm pretty confident that person will be a lot happier with his next purchase rather than "just listening". In fact that person ended up buying an Internet Direct speaker, which I'm sure you probably wouldn't feel comfortable buying.


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## tesseract (Aug 9, 2010)

audioengineer said:


> I think it's cool that someone here does measurements and tries to figure out what works and what doesn't.


Allow me to introduce you to a Home Theater Shack cornerstone, Room EQ Wizard. http://www.hometheatershack.com/forums/equalization-calibration/ 



audioengineer said:


> We're fortunate that most credible speaker companies have finally accepted the value of room specific EQ. It only took 30 years for that to happen (exceptions being companies like Meridian, TAD Electroakustiks, Bose, the nice fellow that runs Tact audio, etc.).


Apples to oranges. I don't think Meridian and Tact (room EQ) or TAD (point source) should be compared to the Bose practice of bouncing sound off walls. EQ'ing can be tailored to an individual room. Direct/Reflecting treats all rooms as if they are the same, with the results varying wildly from room to room.



audioengineer said:


> If I had to do it over again, I'd get a LF+sat system where the mains only play down to 50 or 60Hz.


I do this very thing. I prefer constant directivity mains and multiple subwoofers. This helps deal with FR above Schroeder and the modal FR below, minimal EQ is needed.


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## audioengineer (Feb 8, 2012)

couldn't resist and the kids just headed off to bed.

I didn't say a good waterfall is bad. I am saying what looks like a bad waterfall might still sound very good. 
If a metric can't reliably separate good and bad sound, the vast majority of people are going to misunderstand it and snakeoil salespeople (audio sales people) are going to abuse it. That Pioneer speaker has a pretty clean waterfall with a few exceptions. I've seen individual drivers that are cheap and have clean waterfalls. But in every case, they were poor performers in some other aspect that I consider important. Fixing those other issues would add substantial to the cost and complexity of those drivers. And, I don't find that waterfall to be particularly good. What it shows is that the speaker doesn't use the drivers where they drivers have major cone breakup modes. That's not hard if you give up performance in other dimensions. It is hard if you want to make the transducer good at everything. I agree with you that if a somewhat clean waterfall is the only thing you want, it's not necessarily very expensive. That treble line is likely the first edge hole of the HF driver. Many moderately priced fabric dome drivers don't suffer from that problem (moderate = $25 retail so appropriate for a speaker which retails for under $500). 


"Axiom vs Pioneer" So what? which one sounds more realistic? Which one sounds better? 
Let's recall that this started out on the premise that the vast majority of audio specs don't do the vast majority of the audio buying public any good. If you know what MLSSA is and where it is and isn't valid to use .... then you're in that small fraction of 1% that has a chance of knowing what specs to ignore and how to interpret the rest in a semi-meaningful way. 

"measure poorly" 
Sorry, not a point worth arguing because for me it's ultimately about how it sounds, not about how it measures. I have found very nice sounding speakers from under $100 well into 5 figures. Likewise I have heard horrible sounding speakers from under $100 to well over $10,000 (a pair). Would it matter if the ones that sounded good measured poorly? No more than the bad ones that measure well.

"fine detail"

Er, you just wrote resonant speaker are bad. I'm simply pointing out that you have to quantify what that means if you want to say something useful. If you can't the the statement is useless. Furthermore if you can't set a threshold for what's good/bad then measurements of resonant behavior are also not useful. Again, I'm saying the waterfall doesn't matter as much as you feel it does. It cannot by itself separate the good from the great or even the average from the good ... in so far as what they sound like in a normal listening environment playing music.

BTW, good discussion. I appreciate your position and the thought you're putting into it.


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## audioengineer (Feb 8, 2012)

tesseract said:


> I do this very thing. I prefer constant directivity mains and multiple subwoofers. This helps deal with FR above Schroeder and the modal FR below, minimal EQ is needed.


FWIW, when I was young I thought constant directivity index was a good thing. But my tastes have changed. I also have not found that multiple subs eliminate the need for EQ (yes you didn't say no EQ). I still run into rooms where 3-4 subs are not enough to eliminate high Q room modes which are readily audible. And, I'm NOT saying that EQ is always the first choice to solve the problems. Sharp EQ corrections share many of the same ills as high Q room modes. I'm a firm believer that, within the constraints of the project, one should start by trying to fix acoustic problems at their root with the intelligent application of diffusion, absorption, and location. The problem for lay people is that usually requires substantial amounts of space, time and money. Often EQ ends up being a better value for them, even if it's not technically or audibly the best possible solution.

Bash or embrace them. Bose made a substantial contribution toward introducing room correction EQ to the marketplace. Whether you think that is evil or not, I argue that it did a lot more good than harm. And it wasn't marketing. It was based on sound ideas from a guy who knows a lot more about acoustics than you or me.


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## tesseract (Aug 9, 2010)

audioengineer said:


> FWIW, when I was young I thought constant directivity index was a good thing. But my tastes have changed.


Constant directivity is back and making a splash in the form of waveguides and dynamic dipoles. Planar and ribbon dipoles never left once introduced.



> I also have not found that multiple subs eliminate the need for EQ (yes you didn't say no EQ). I still run into rooms where 3-4 subs are not enough to eliminate high Q room modes which are readily audible. And, I'm NOT saying that EQ is always the first choice to solve the problems. Sharp EQ corrections share many of the same ills as high Q room modes.


I can agree for the most part, properly integrated multiple subs are not a panacea for all rooms, but have been proven to be helpful in reducing the amount of EQ needed. 

This is helpful in avoiding those sharp EQ corrections that certainly can cause more harm than good.



> I'm a firm believer that, within the constraints of the project, one should start by trying to fix acoustic problems at their root with the intelligent application of diffusion, absorption, and location.


Root cause of the problem IS location, both speaker and listening position. Diffusion and absorption (and EQ) treat the problem. lddude:

I tend to eschew room treatments and EQ. The minimal EQ I use is necessary to boost the bottom end of a sealed subwoofer systems natural roll off. Otherwise, I let room gain (which I think of in terms of boundary reinforcement and pressure vessel gain) do the work in the modal domain.


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> I am saying what looks like a bad waterfall might still sound very good.
> If a metric can't reliably separate good and bad sound, the vast majority of people are going to misunderstand it.....I've seen individual drivers that are cheap and have clean waterfalls. But in every case, they were poor performers in some other aspect that I consider important.


There's speakers with clean waterfalls that sound bad. But there aren't many speakers with poor waterfalls that sound good - unless we're talking about what people "think" sounds good without any valid frame of reference. Returning to bose, they use paper cone full range drivers which certainly won't "ring" like metal drivers but i wouldn't be surprised if their waterfalls are extremely messy. What that means is they won't have the detail of a good speaker at the same price point.



> That's not hard if you give up performance in other dimensions. It is hard if you want to make the transducer good at everything. I agree with you that if a somewhat clean waterfall is the only thing you want, it's not necessarily very expensive. That treble line is likely the first edge hole of the HF driver. Many moderately priced fabric dome drivers don't suffer from that problem (moderate = $25 retail so appropriate for a speaker which retails for under $500).


We're talking about a more likely $7/ea tweeter here. The speakers are $100/pr retail. It's not an issue either way - at 17khz. 



> "Axiom vs Pioneer" So what? which one sounds more realistic? Which one sounds better?


Wrong questions - Which one is _less likely to sound fatiguing_?? Which one is _more worthy of an audition_??



> Sorry, not a point worth arguing because for me it's ultimately about how it sounds, not about how it measures. I have found very nice sounding speakers from under $100 well into 5 figures. Likewise I have heard horrible sounding speakers from under $100 to well over $10,000 (a pair). Would it matter if the ones that sounded good measured poorly? No more than the bad ones that measure well.


You keep saying "sounded good" and "sounded poor". The real question is, does it "Sound accurate and resolving" or does it sound "inaccurate and unresolving"?. There's innaccurate and unresolving speakers that some people think sounds good. There aren't many innaccurate and unresolving speakers that measure good.



> Er, you just wrote resonant speaker are bad. I'm simply pointing out that you have to quantify what that means if you want to say something useful. If you can't the the statement is useless. Furthermore if you can't set a threshold for what's good/bad then measurements of resonant behavior are also not useful. Again, I'm saying the waterfall doesn't matter as much as you feel it does. It cannot by itself separate the good from the great or even the average from the good ... in so far as what they sound like in a normal listening environment playing music.


A person like Sean Olive would be more qualified to quantify this sort of thing. I'm not a loudspeaker engineer nor am I even in the business. I can only correlate what I hear to the measurements, and correlate the measurements to what little research that i've read has to say. 

I don't have the book on my right here, but Toole's book very carefully defines the measurable behavior of resonances and the observed correlation to audibility. All resonances are unwanted, but not all resonances ring the same way. In general, it only makes sense for a loudspeaker to have good design and good design leads to clean waterfalls (I`m not implying the vice versa)

That's not a knock on metal cone speakers either. In fact i'd say the best speakers out there all use very tricky metal or ceramic cones (or perhaps planar drivers in the case of the Philharmonics). But they also use more complex crossover networks than a simple "cap and coil" found in mediocre speakers.

Subjectively, it's possible for anything to seem top-notch. We all process sound differently, even if we hear the same thing. But I'd hope the goal for all companies fis not speakers we process as pleasing, but speakers that are within the budget limitations, true to the source material, with minimal exaggeration or omission. 

So yes, you need smoothly tapering power response, flat frequency response, low distortion, and minimal resonance. Yes, there's places companies can cut corners, too that won't show up on a typical spec sheet - "absence of evidence is not evidence of absence". I think power compression is one such key example. Speakers that compress dynamic range are undesirable. 

I'm definitely more inclined to buy a pair of Philharmonic speakers based on the measurements, than to go into a Future Shop and ask for an audition of Bose. Call it a whatever you like... it's obvious to me the _goals_.



> Bash or embrace them. Bose made a substantial contribution toward introducing room correction EQ to the marketplace. Whether you think that is evil or not, I argue that it did a lot more good than harm. And it wasn't marketing. It was based on sound ideas from a guy who knows a moo baby moo of a lot more about acoustics than you or me.


Room EQ above the shroeder frequency is undesirable. You can only equalize total power response, and in a good speaker the power response is properly tapering without bloom. In a room such issues are best dealt with acoustically, not electrically, assuming they were ever an issue in the first place.



> FWIW, when I was young I thought constant directivity index was a good thing. But my tastes have changed.


While the absolute value of the DI itself is debatable/preferential, I can't see any scenario where a matching DI is not desirable, beyond cost/complexity cutting. Everything from a TAD Reference One, Linkwitz Orion, KEF Q900, Geddes Abbey, Revel Salon2, JBL 6332, Audiokinesis Planetarium, Tannoy KR, all have different directivity indeces, but make an effort towards matching DI and very also have similar total power response. 

To not have matching DI, is to welcome sound power holes, and accompanying tweeter bloom. I'd love to see an explanation for why that's desirable, when that just imbalances reflected sound. The only reason, I'd imagine, is if you truly think the room is more significant than the speaker's interaction with it, which would imply that late arriving reflected sound impacts our perception of timbre or imaging as significantly as early arriving sound, which is not true for the most part, barring extreme/unrealistic scenarios. The only time where the room dominates the sound, is when speakers have excessive early reflectived energy relative to direct arriving sound. IE Omni or bose 901 speakers near walls. In these cases the room can color the sound.



> Diffusion and absorption (and EQ) treat the problem.


+1

If you look at Harman's reference room:










The main thing you'll notice is that it isn't over-treated at all, even though it was built from ground-up. There's absorption behind the speaker (because most speakers will have boundary cancellations when distant from a wall, though not necessarily all), the first reflection points are very much bare wall, and even floor/ceiling reflections aren't treated. That`s because the speakers in the room aren`t as problematic as Ethan Winer et al might make one believe.

It's debatable how necessary absorption/diffusion is in a typical living room with its own absorptive/diffusive elements. My living room is probably less "bare" than that. Yes most speakers will benefit from bass traps, because they radiate omnidirectionally below most speakers' shroeder frequency. But not all speakers do so. Cardioids certainly don't.

The room is not the root of all problems. It almost invariantly starts and stops at the speaker. That said, it's about tradeoffs but that doesn't mean to "throw it all out the window". The behavior of a speaker can very reliably be predicted above and even below the shroeder frequency. Auditioning in you own room is important but it's not vital, either. If a well-measuring speaker sounds good in one room, it should not sound starkly different in yours. Of course there's difficult rooms but they're not the majority. Bass is the only place where the room makes an eye-opening difference, and that's because 99% of speakers are omni in the bass. Even then though, the anechoic response in the bass can show which speakers will excite more room modes. "A room" is never an excuse for 4-5db peaks in anechoic response.


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## gdstupak (Jul 13, 2010)

tesseract said:


> Apples to oranges. I don't think Meridian and Tact (room EQ) or TAD (point source) should be compared to the Bose practice of bouncing sound off walls. EQ'ing can be tailored to an individual room. Direct/Reflecting treats all rooms as if they are the same, with the results varying wildly from room to room.


He is referring to Bose active equalizers and not Bose direct/reflecting characteristics. 
Awhile ago Bose started using active equalizers with some speakers (i.e. 901's). 
It's amazing how people on this site criticize Bose for using EQ (i.e. "Bose sound is so terrible that they need EQ to make it sound decent"), but then they praise other equipment for the same thing (Audyssey and subwoofers with built in room correction (that's EQ)).

This is a great thread, I'm learning alot more about measurements, thanks GranteedEV and audioengineer.


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## audioengineer (Feb 8, 2012)

GranteedEV,
You seem like a genuinely nice guy. But, it's clear this discussion is not going anywhere because you put measurements at the forefront with little regard to how they actually correlate with what you hear. 

Yes, it would be really nice if a speaker that sounds good also measures really really well. But, which is more important (and you can substitute accurate or any other subjective term you like for the word "good")? The point of technical measurements is to find a way to quantify things which we hope are correlated to our perception of good and bad (preferred or not, in some cases). Not the other way around, as you suggest.


If audio is about seeing measurements, that's fine for you because that's a value statement ... and value is a deeply personal thing. And in fact many audio companies behave as though they design for people who want the best specs first and whose ability to judge subjectively is strongly biased by what they've seen in the measurements. 

This conversation is going in a direction similar to something that happened nearly 20 years ago.
Back in the early days of 'www' there was a nice chap named Howard Ferstler that was the epitome of the audio armchair quarterback. He was intelligent enough to be able to read and get a lot out of the AES technical literature, and thus he understood a great many right ideas about audio and hearing. But he didn't have the capacity to understand audio and hearing at the ASA level, so ultimately he also had many blind spots due to his irrational reliance on published measurements and a refusal to acknowledge new ideas that challenged old thinking. You know, the kind of guy that thinks SNR as defined by the audio industry 80 years ago is more important than modern measures of perceived noise partial loudness. In the end, he was dismissed as a well meaning hobbyist by the various IEEE fellows and other true audio experts, but I believe he still continues to write prolifically and generally in the right direction about audio. 

A nice, slightly befuddled, hobbyist. We need people like him to balance out the audiophile lunatics (not all, just most). But he errs too far on the side of specsmanship over perception. On the whole, a plus to consumers, but still to be taken with a chunk of salt.

Anyway...



GranteedEV said:


> (snip)
> The reality is that it's the first 5ms, maybe 10ms of what we hear that contributes to timbre perception, and the first 10-15ms that contribute to imaging. The character of the room will still affect the reflected sound, but because of how our brains hear, it will mostly affect our perception of "soundstage" / spaciousness. The reality is that you can very accurately predict a the sound of a speaker based on its measurable behaviour with respect to polar response.



Much of what you say has elements of truth in it. However, much of what you're writing is also grossly simplified into generalities that have not and will not hold up under technical scrutiny (subjective hearing perception is a science, FYI). There is lots of text about things like the contribution of early energy to timbre and the Haas effect yada yada. That early energy is pretty important to the perception of timbre, but it isn't exclusive. Obviously, it's dependent on the actual signal (drum tap, struck piano chord, sustained note on a French horn, etc.). Next you say the room mostly affects sound stage not timbre of the reproduced sounds. I think you'd better get thee to your lab and your range of target listening rooms and experiment a bit. Polar response, power response, on-axis, it's all useful data to someone who knows how to make sense of it (which is some miniscule fraction of 1% of the public). However, no single one is a reliable indicator of what timbre will be in an unspecified room. This has been shown to be true over and over again in technical publications and it is to be expected from what is known about hearing perception. Well, I'm sure this is a case of agree to disagree. 



GranteedEV said:


> A speaker with controlled, uniform radiation pattern and flat frequency response will more or less sound like the source content. Sure there will be differences as there's no perfect speaker but speakers with controlled on and off-axis response sound more similar than not.


 Yes, this type of design will more accurately reproduce the input with just gain and perhaps some band limiting). But, you don't know how it's going to sound in a room. Will you be able to say if it's good or rotten, absolutely. Will you know if it's good or great, no. Will tell you your preference between two product that sound different but measure similarly, no. So, in the end is it really that useful compared to listening?


As far as coherency is concerned, it's not a stereo effect. Coherency is best described as "mono imaging" and best described as phase-difference in the crossover region.[/QUOTE]
Sorry, but this statement clearly shows you don't understand hearing perception, or how it's affected by physical acoustics. I'm not trying to be offensive, but a century of good science and the work of many distinguished people/companies in the audio business clearly show this to be the case. 




GranteedEV said:


> Most certainly, because those specs will ultimately tell you 90% of how it will sound in your own home.


I should going to stop here because I don't know what you mean by "90%" 
Please get thee down to Best Buy and find the products that specify these things we're discussing, such as polar radiation characteristics as a function of time and frequency (bands are okay). That's at least 40 to 60 graphs. That's not a bad start to predicting what the speaker might sound like, depending on your room acoustics.




GranteedEV said:


> Olive/Toole's research even shows that almost invariably, once biases are removed, people prefer more measurably accurate systems, though.


I know Floyd and Sean. Both really great guys. In the right circumstances yes people do prefer accuracy over gross inaccuracy. However, when given a choice via something like tone controls on a system that has flat on-axis and power response (IN THE ROOM wrt the LISTENING POSITION), it's interesting to note that a significant % of the population won't leave them flat. 



GranteedEV said:


> That's why when you look at the spec sheet:
> http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=569
> You get _meaningful information_ as it pertains to that speaker's accuracy.


For a studio engineer who wants to spend $3200 for a stereo pair, yes there's useful info here. It's by no means complete and it needs to be taken into context with the intended room. For the audio consumer, most of that information won't be interpreted meaningfully. I've heard these speakers and others in the same design family. Very good stuff. Not as good as other product that doesn't measure as well in the laboratory. And, I've heard on numerous occasions superbly designed speakers like this sound mostly wretched due to room and setup. Some of these were millon dollar "professional" jobs to boot, so it's no shame to think you know it all from reading a few AES papers (e.g. you're in good company).


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> GranteedEV,
> You seem like a genuinely nice guy. But, it's clear this discussion is not going anywhere because you put measurements at the forefront with little regard to how they actually correlate with what you hear.


The only things I put at the forefront are ability of a speaker to sound similar in an audition room to home and saving time from being led in a completely different direction.



> But, which is more important (and you can substitute accurate or any other subjective term you like for the word "good")?


What's important is to get the true-to-source sound I want without being tricked by my brain by listening to all the sub-par products out there. It's a three stage process

1) To weed out things which fail to support themselves with adequate measurements either 1st or 3rd party. WHY should I waste my time on other stuff?
2) To audition those things, which thanks to their design will not sound dissimilar in my room. It has been my subjectife experience whether your subjective experience disagrees, that speakers and their interaction with the room is the vast majority of what we hear, not the room itself.
3) To finally try to live with a purchase and over time hopefully NOT identify ills of a speaker.



> The point of technical measurements is to find a way to quantify things which we hope are correlated to our perception of good and bad


Based on your posts, I was under the impression that the point of technical measurements as specifications didn't exist at all.



> And in fact many audio companies behave as though they design for people who want the best specs first and whose ability to judge subjectively is strongly biased by what they've seen in the measurements.


... which, as negative as you make it sound.. is ...still... more comforting than those which make speakers moderately better than a clock radio and sell it to the unassuming based on what will grab their attention. The reality is that we ALL have biases when listening to speakers in rooms. We as individuals form our preferences based on countless factors. We want the biggest, deepest soundstage, even if the speaker can't play back a violin without sounding like nails on a chalkboard. We want the smallest, most compact speaker possible, even if that speaker falls apart on percussion. We want the speaker that envelopes us in this magical blanket of sound, even if we go home and all we hear when we watch moviesssssssss isssss ssssomething that makessss usss cringccccchhhhh.

It's not nonsense at all to want speakers that measure well and sound accurate. It's easy to give ""specsmanship"" a bad name, but when you purchase pickup trucks don't you want the one that rides smoothest but also has the most horsepower? It's simply covering all your bases. Of course for most people anything better than built in speakers is often plenty. Many people just aren't perceptive to the issues in speakers.

However, much of what you're writing is also grossly simplified into generalities that have not and will not hold up under technical scrutiny (subjective hearing perception is a science, FYI). There is lots of text about things like the contribution of early energy to timbre and the Haas effect yada yada. That early energy is pretty important to the perception of timbre, but it isn't exclusive. Obviously, it's dependent on the actual signal (drum tap, struck piano chord, sustained note on a French horn, etc.). [/quote]

Excellent point. Now explain to me how ones goes about getting a sustained note on a french horn to sound like that??? Do some speakers magically do it better than others?? Do some rooms magically do it better than others?? Do I keep crossing my fingers and hoping I get just the right combination??? As I said earlier, speakers with an unnaturally high ratio of reflected sound to direct sound are most guilty of messing up the sound of horns in small rooms based on subjective/anecdotal evidence. In these cases 'Flat is Wrong'. But that's still a wholistic picture of the speaker, not the room.

Neutral rooms are nice and preferable but not vital to get 90% of the way there. Our brains know the rooms in our homes. Yes there's really bad rooms which our brains will recognize during everyday conversation as being difficult to speak clearly in. But on a whole good speakers in typical rooms should not sound inaccurate.



> Next you say the room mostly affects sound stage not timbre of the reproduced sounds.


Most rooms will have three early reflections contributing to timbre perception. Ceiling, floor, and nearest side wall. You can add some more very early reflections for omni / bipole speakers in typical placement. Most rooms will have a given optimal spl, above and below which, they won't sound as believable. Treated rooms raise that spl, live rooms lower it.

At that optimal SPL, the ceiling and nearest side wall are the least desirable reflections out of the three. The spectral balance of sound radiated off the nearest side wall will make or break timbre perception. Better speakers will always have a smoothly tapering as you go up in frequency, reduced in amplitude reflection. Very directive speakers will actually take this reflection away for the most part. The geddes and audiokinesis stuff do exactly this.

The room can affect timbre, but not "necessarily" - only typically. 



> Polar response, power response, on-axis, it's all useful data to someone who knows how to make sense of it (which is some miniscule fraction of 1% of the public).


If such is the case, then what harm is there in supplying the data in the form of maybe a contour map? Surely 99% of the public will just gloss over it. It seems to me that most companies fear their polar data, and many even fear their axial data, because they don't and don't intend to make accurate measuring and thus accurate sounding speakers in a wide variety of rooms.



> However, no single one is a reliable indicator of what timbre will be in an unspecified room.


Sure it is, to a reasonable extent. To those chasing after extremes it's true that a neutral custom room is desirable (Though most treated rooms are worse than they are better IMO). To the rest of us, it makes sense to use speakers which do many things well and don't try to fool us with a sly audition.



> But, you don't know how it's going to sound in a room. Will you be able to say if it's good or rotten, absolutely. Will you know if it's good or great, no. Will tell you your preference between two product that sound different but measure similarly, no. So, in the end is it really that useful compared to listening?


Yes, it is. It will tell some of uswhich products to compare and which products to throw out the window (the majority). Others don't care anyways. So why not?

Fact is, Earl Geddes is the ultimate proponent of speakers measuring well thus sounding accurate. Yet if you look at his sales on various forums, people only buy them after hearing them.

Truth is speakers are a personal investment and if one wants all the boom n sizzle Best Buy can sell, they have every right to purchase it. But if someone wants to find a decent spec sheet, they get the short end of the stick most of the time.


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## GranteedEV (Aug 8, 2010)

> Please get thee down to Best Buy and find the products that specify these things we're discussing, such as polar radiation characteristics as a function of time and frequency (bands are okay). That's at least 40 to 60 graphs. That's not a bad start to predicting what the speaker might sound like, depending on your room acoustics.


All it really needs to be is a polar contour map. Regardless though, the lack of these specs is the issue in the first place when you scroll up to the very first post in the thread. When people want information about their purchase, all they get is fluff. Whether they can comprehend it should not be a decision left up to the marketing department. But companies want ambiguity. They want to lead you astray. Mostly because that is what they're selling.



> I know Floyd and Sean. Both really great guys. In the right circumstances yes people do prefer accuracy over gross inaccuracy. However, when given a choice via something like tone controls on a system that has flat on-axis and power response (IN THE ROOM wrt the LISTENING POSITION), it's interesting to note that a significant % of the population won't leave them flat.


Tone controls are tone controls. Individual preference and often dictated by the recording. Speakers have no excuse for a built in tone control whatsoever. Speakers are a reproduction tool. If someone wants to use tone controls there's much more advanced, defeatable methods to do so.



> For a studio engineer who wants to spend $3200 for a stereo pair, yes there's useful info here. It's by no means complete and it needs to be taken into context with the intended room.


It's far more complete than the Bose which you were championing earlier. Again, given the two extremes of public information, which speaker is a bigger waste of time to sit down and audition?



> For the audio consumer, most of that information won't be interpreted meaningfully.


And to judge the consumer, you are whom?



> I've heard these speakers and others in the same design family. Very good stuff. Not as good as other product that doesn't measure as well in the laboratory.


That's your subjective opinion. Perfectly valid but of as much use to me looking for speakers to audition as an amazon review.


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## GranteedEV (Aug 8, 2010)

> Please get thee down to Best Buy and find the products that specify these things we're discussing, such as polar radiation characteristics as a function of time and frequency (bands are okay). That's at least 40 to 60 graphs. That's not a bad start to predicting what the speaker might sound like, depending on your room acoustics.


All it really needs to be is a polar contour map. Regardless though, the lack of these specs is the issue in the first place when you scroll up to the very first post in the thread. When people want information about their purchase, all they get is fluff. Whether they can comprehend it should not be a decision left up to the marketing department. But companies want ambiguity. They want to lead you astray. Mostly because that is what they're selling.



> I know Floyd and Sean. Both really great guys. In the right circumstances yes people do prefer accuracy over gross inaccuracy. However, when given a choice via something like tone controls on a system that has flat on-axis and power response (IN THE ROOM wrt the LISTENING POSITION), it's interesting to note that a significant % of the population won't leave them flat.


Tone controls are tone controls. Individual preference and often dictated by the recording. Speakers have no excuse for a built in tone control whatsoever. Speakers are a reproduction tool. If someone wants to use tone controls there's much more advanced, defeatable methods to do so.



> For a studio engineer who wants to spend $3200 for a stereo pair, yes there's useful info here. It's by no means complete and it needs to be taken into context with the intended room.


It's far more complete than the Bose which you were championing earlier.



> For the audio consumer, most of that information won't be interpreted meaningfully.


And to judge the consumer, you are whom?

If the information's not there, of course they/we are unable to interpret it. If the information is there, then we adapt and seek explanation. It goes right back to the earlier discussion on impedance charts. What's more useful... a nominal impedance number or a z-chart?



> I've heard these speakers and others in the same design family. Very good stuff. Not as good as other product that doesn't measure as well in the laboratory.


That's your subjective opinion. Perfectly valid but of as much use to me looking for speakers out of hundreds to audition as an amazon review is. It'd be nice to audition all 50 speakers available to me in my city for 2-3 hours at a time.... Just not realistic. And often people end up with speakers not even available in their City.


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## audioengineer (Feb 8, 2012)

GranteedEV said:


> The only things I put at the forefront are ability of a speaker to sound similar in an audition room to home and saving time from being led in a completely different direction.


and then you say



GranteedEV said:


> speakers with an unnaturally high ratio of reflected sound to direct sound are most guilty of messing up the sound of horns in small rooms
> Most rooms will have a given optimal spl, above and below which, they won't sound as believable.(snip)
> The spectral balance of sound radiated off the nearest side wall will make or break timbre perception. (snip)
> The room can affect timbre, but not "necessarily" - only typically. (snip)


So, your definition of a good speaker is one whose sound is independent of the room/environment. I get it.



GranteedEV said:


> What's important is to get the true-to-source sound I want without being tricked by my brain by listening to all the sub-par products out there.


I'm not sure I fully understand the emphasis on audio companies tricking your brain.



GranteedEV said:


> The reality is that we ALL have biases when listening to speakers in rooms. We as individuals form our preferences based on countless factors.


That's what I've been trying to tell you and that's why I recommend the typical person chose based on listening rather than trying to figure out what it might sound like by looking at inadequate and/or misleading graphs and numbers. 



GranteedEV said:


> We want the biggest, deepest soundstage,


If you delete the "est" part I don't see what's wrong with desiring a realistic sense of acoustic space.
Are you the type that likes a totally dry and hyper-revealing sound that is far removed from what you'd ever hear in real life? I was once in a recording studio (one of the very very best in the world) during a live session. One of the other clients would walk up and stand 20" in front of one of the musicians, and then later complain that he couldn't hear that same level of "clarity" in the 2-channel mixdown. Hyper-clarity is cool, and there are systems that cater to that preference. Not for me.




GranteedEV said:


> even if the speaker can't play back a violin without sounding like nails on a chalkboard.


Okay, you have to tell us what speaker makes a violin sound like "nails on a chalkboard." Seriously. And tell us the exact recording/track to use so we get as close to your experience as possible. I'll go down to the local supermall and try it out personally. Really.



GranteedEV said:


> We want the smallest, most compact speaker possible, even if that speaker falls apart on percussion. We want the speaker that envelopes us in this magical blanket of sound, even if we go home and all we hear when we watch moviesssssssss isssss ssssomething that makessss usss cringccccchhhhh.


You want the smallest speaker but you don't like the sound? The rational thing to do is to live with the sound or change your tolerance for size. Seems pretty simple to me. Same thing regarding listener envelopment and any other perceived audio quality. It's up to you to set your preferences and make your choices.

You need not feel obligated to accept what you don't like. BTW, listener envelopment is an important aspect of the live experience, so I wouldn't fault someone if they trade off other aspects of good audio performance to get it. I might disagree with your preference, but preference is not something I believe iw worth arguing.




GranteedEV said:


> It's easy to give ""specsmanship"" a bad name, but when you purchase pickup trucks don't you want the one that rides smoothest but also has the most horsepower?


Nope, I care about acceleration with payload up an incline at 5000ft above sea level, fuel efficiency, cargo space, MTBF. Horsepower is an intermediate value that does not directly benefit me, the driver. A Porsche GT3 has less horse power than a Viper, but which one is faster around a track? Lotus won the world championship with less horsepower than everyone else. HP is not important. 

This is such a classic audio newbie mistake. On a regular basis I'm asked how amplifier watts one should get for a given price. I consistently say that's a nonsense question. What matters is what SPL you need at your listening postion for a given bandwidth and distortion level (ask me what metric). 




GranteedEV said:


> As I said earlier, speakers with an unnaturally high ratio of reflected sound to direct sound are most guilty of messing up the sound of horns in small rooms based on subjective/anecdotal evidence.


#1: good that you acknowledge the room is important. I though we'd never get thru that point.
#2: "unnaturally" implies you have a reference for natural or correct. This is a matter of preference and opinion, not fact. 




GranteedEV said:


> In these cases 'Flat is Wrong'. But that's still a wholistic picture of the speaker, not the room.


Oh boy ... 




GranteedEV said:


> It seems to me that most companies fear their polar data, and many even fear their axial data, because they don't and don't intend to make accurate measuring and thus accurate sounding speakers in a wide variety of rooms.


You are guessing based on the visible behavior of marketing departments. Yes, that's all you have to go on, but that doesn't make your guessing reasonable or right. Have you ever worked for a major audio company, or for a major company producing any type of consumer product?




GranteedEV said:


> don't try to fool us with a sly audition.


I wish you'd give that a rest. Companies product products, consumers try them and buy what they like. Some consumers learn to like certain things based on marketing, and in audio EVERYONE markets. My point is 99.999% of the time specs are there for marketing purposes, just as all the other things audio ads say. My recommendation is to try to ignore all the verbal fluff and generally useless numbers since what matters is if you like the sound ... not the specs or marketing copy.



Fact is, Earl Geddes is the ultimate proponent of speakers measuring well thus sounding accurate. Yet if you look at his sales on various forums, people only buy them after hearing them.



GranteedEV said:


> if someone wants to find a decent spec sheet, they get the short end of the stick most of the time.


That I can agree with. The specs the consumer has access to are generally speaking of little to no value. I think you've done a good job supporting that claim with that statement.



Now, what if all audio companies produce reams of accurate and useful technical measurements, and audio engineering was a required course throughout the nation from K-12. And what if the material taught in that curriculum were technically sound (yeah, like that's going to happen). In that alternate super-geeky universe, I'd reverse my position and say ... audio specs are quite useful and generally do a good job guiding the vast majority of customers into making better purchases of audio equipment.


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## audioengineer (Feb 8, 2012)

GranteedEV said:


> (snip)
> It's far more complete than the Bose which you were championing earlier.


Please accuse me of things I have not done. I have not and will not championing any brand or speaker.
You're trying to read between the lines and getting it wrong. Please ... stick to facts and not misread innuendo.





GranteedEV said:


> And to judge the consumer, you are whom?


I am an audio engineer and I interface with audio customers throughout the world. They tell me what they think, what they believe, and I get to test their subjective perceptions all the time. My data and opinions are only as good as this makes it. It's fair for everyone to question everything I say. I could be totally full of bull.




GranteedEV said:


> That's your subjective opinion. Perfectly valid but of as much use to me looking for speakers to audition as an amazon review.


You've gotten yourself all turned around and confused. You are not the target of those comments on minimal audio specs. You are a hobbyist who invests a substantial amount of time and effort trying to educate your self. That's really laudable. Really. But, go back and read the OP's post as well as mine.


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> Please accuse me of things I have not done. I have not and will not championing any brand or speaker.
> You're trying to read between the lines and getting it wrong. Please ... stick to facts and not misread innuendo.


Hi, you must have misinterpreted my meaning... return your focus to the context of the JBL specs.... I meant that you were supporting Bose's marketing strategy (of with holding anything along the lines of specifications). 

To quote yourself



You said:


> I am ABSOLUTELY justifying Bose's lack of numerical audio performance specifications.


Now I found this seemed to conflict with your critcism of JBL's specs...the JBL specs are either useful (apparently, only to trained professionals), or they're absolutely useless(apparently to the other 99.99% of us), and you seem to be rejecting any gray area in between. If you "Absolutely Justify" Bose's position, then i don't see any reason to be criticising the "completeness" of JBL's specs.

Consider acknowledging that "yes, there exists a gray area where non-professionals can comprehend well laid out specifications that help them in their purchase, and withholding this information helps no one".

I don't think anyone believes they know what a speaker truly sounds like without hearing it, but I can definitely have some idea from measurements.


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## tesseract (Aug 9, 2010)

gdstupak said:


> He is referring to Bose active equalizers and not Bose direct/reflecting characteristics.
> Awhile ago Bose started using active equalizers with some speakers (i.e. 901's).
> It's amazing how people on this site criticize Bose for using EQ (i.e. "Bose sound is so terrible that they need EQ to make it sound decent"), but then they praise other equipment for the same thing (Audyssey and subwoofers with built in room correction (that's EQ)).


We are all familiar with the 901 and it's EQ, and the 901 uses the Direct/Reflecting principle. Audioengineer has spoken of both EQ and using the room reflections (Toole), hence my response.

Bose Active EQ and Audyssey are, once again, apples to oranges. No one should compare this to Tact, either. 

Audyssey and Tact controls parametric EQ, crossover, polarity, delays and levels in the digital domain, averaging these out over a large listening area. Calling these EQ's is a gross over simplification.

The Bose Active EQ is nothing more than an analog tone control, and really only good for tuning the main listening position. It is also good for introducing phase shift anomalies. This tone control was not exactly revolutionary when Bose introduced it as a package deal with the 901, but is was a good move from a marketing standpoint. 



> This is a great thread, I'm learning alot more about measurements, thanks GranteedEV and audioengineer.


This is a great thread, for even more on measurements, check out our REW forum. Really helpful for determining EQ settings. :T


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## tesseract (Aug 9, 2010)

audioengineer said:


> But, most of you wouldn't understand these measurements and I don't think I'm allowed to post them anyway because they're the property of my employer


You might be surprised at what we would understand. Could you divulge the nature of the measurements without giving away (Bose's?) intellectual property?


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## audioengineer (Feb 8, 2012)

GranteedEV said:


> (snip)
> Now I found this seemed to conflict with your critcism of JBL's specs...the JBL specs are either useful (apparently, only to trained professionals), or they're absolutely useless(apparently to the other 99.99% of us), and you seem to be rejecting any gray area in between. If you "Absolutely Justify" Bose's position, then i don't see any reason to be criticising the "completeness" of JBL's specs.


All within the right context. My context of the consumer audio customer buying consumer audio equipment. 

I hope I've been clear that this excludes audio engineers and the small minority of hobbyists that successfully pursue a better understanding of objective measurements. This JBL speaker is aimed at the professional market. It's, IMHO, not a reference for what should be done in consumer audio. 

Pro audio companies do publish specs, and I'm not arguing against that at all.
However, even in pro audio, the amount of specs provided varies. Let's save that topic for later. 

So, let me correct myself and say the utility of specs is a continuum which depends on how good the specs are as well as the ability of the reader to interpret them. It is my experience that both are very low in practice, giving manufacturers and retailers fodder for misguiding consumers.

If I gave the impression that there's no grey, that's wrong. But, I do support any audio company's choice to publish a minimum of specs for the consumption of audio consumers because the majority of specs are either not useful or not interpreted correctly. And, "minimum" is smaller for HTIB than for individual components.


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> So, your definition of a good speaker is one whose sound is independent of the room/environment. I get it.


Not to any extreme extent, but a good speaker won't pull a chameleon act in different typical environments.



> I'm not sure I fully understand the emphasis on audio companies tricking your brain.


Speakers are a big investment. There's so many speakers out there that audio companies are always trying to get a person to gravitate their way. Unfortunately this is often at the expense of that consumer's best interests in the long term. It's a classic case of "Short Term Impressions" vs "Long Term Enjoyment". At times they can be mutually exclusive and this is where measurements come in.



> That's what I've been trying to tell you and that's why I recommend the typical person chose based on listening rather than trying to figure out what it might sound like by looking at inadequate and/or misleading graphs and numbers.


..but..I don't think anyone here has advocated "trying to figure out what it might sound like by looking at... graphs/numbers". 



> If you delete the "est" part I don't see what's wrong with desiring a realistic sense of acoustic space.
> Are you the type that likes a totally dry and hyper-revealing sound that is far removed from what you'd ever hear in real life? I was once in a recording studio (one of the very very best in the world) during a live session. One of the other clients would walk up and stand 20" in front of one of the musicians, and then later complain that he couldn't hear that same level of "clarity" in the 2-channel mixdown. Hyper-clarity is cool, and there are systems that cater to that preference. Not for me.


Absolutely not. On the contrary, actually. My only point is that there is more than one dimension towards auditioning a speaker. The problem with "listening only" is that it's not only easy, but likely, for a listener to be captivated by one dimension of a speaker's sound, and forget about paying attention to the other dimensions. The end result is that in the long term, those other dimensions _do_ surface. So yes, a speaker need not only impress in an audition but also measure well in various factors, as this will hopefully maximize the chance of long term enjoyment... something most companies are not interested in. Often aesthetics are as biasing as anything else.

My only point is that measurements are FAR from the only source of bias or preference in a listening test. They, at least, represent a positive one.



> BTW, listener envelopment is an important aspect of the live experience, so I wouldn't fault someone if they trade off other aspects of good audio performance to get it.


Listener envelopment in stereo recordings comes from the room, yet all rooms are different. One thing's for sure, though... if a speaker needs absorption panels to sound timbrally correct, there is an obvious tradeoff in listener envelopment. 



> Nope, I care about acceleration with payload up an incline at 5000ft above sea level, fuel efficiency, cargo space, MTBF. Horsepower is an intermediate value that does not directly benefit me, the driver. A Porsche GT3 has less horse power than a Viper, but which one is faster around a track? Lotus won the world championship with less horsepower than everyone else. HP is not important.


Thank you. That was my point exactly. You listed a bunch of specifications/features that you would look for given your knowledge of auto. But if the manufacturer is only giving me HP (if that), then the only thing one can use to make a decision is how smoothly it test drives. See where I've been getting at?



> #1: good that you acknowledge the room is important. I though we'd never get thru that point.
> #2: "unnaturally" implies you have a reference for natural or correct. This is a matter of preference and opinion, not fact.


The room is of course important, but above the shroeder frequency, only because of how the speaker loads it. Yes a neutral room is still the ideal but it's not vital or normally practical. It starts at the speaker for the majority of people.

As far as naturalness of Omni or Bose Direct/Reflecting, you're right, but the first thing to note that small rooms are rarely the refernece. Even if an instrument is omnidirectional itself, it will never be near a corner in a large acoustic space. It only makes sense to have some dominance of direct sound over reflected sound. There's no absolute value for an optimal Direct to reflected ratio (it's preference) but it's safe to say that omni loads most rooms in a very unrealistic manner, because placement causes very early reflections to dominate on a whole. Reflections are NOT bad, but very early reflections are definitely bad. To treat a room might reduce very early reflections but it also reduces late arriving reflections. See the problem with absorption?



> Companies product products, consumers try them and buy what they like. Some consumers learn to like certain things based on marketing, and in audio EVERYONE markets.


Do the consumers buy what they like, though? Or do they buy what impresses them in a short audition? Are those the same thing?



> My recommendation is to try to ignore all the verbal fluff and generally useless numbers since what matters is if you like the sound ... not the specs or marketing copy.


This returns to the question I posed of "whom" like the sound. People making their first upgrade from harsh TV speakers and stock Car stereos will of course like the sound. 



> Now, what if all audio companies produce reams of accurate and useful technical measurements,


Then people who care, learn to purchase products which better suit their requirements, and people who don't care, don't bother. Last I checked, having an informative website was good business practice.



> and audio engineering was a required course throughout the nation from K-12. And what if the material taught in that curriculum were technically sound (yeah, like that's going to happen).


This is where you're getting into hyperbole. Let's get right back to the truck discussion. Do I need a auto manufacturing engineering degree to read the spec sheet for a truck? In fact I don't know a whole lot about pickup trucks. Never needed one, probably never will. How do I go about purchasing a truck, if I don't know a thing about them? Just drive the one i like in a test drive and not worry about anything else? It's only sensible for there to be SOME research into my $30,000 purchase. No not everyone is sensible and yes there are some who go by hear-say and reputation alone, or buy into the wrong specifications. 

It's just my opinion that it's a manufacturer's responsibility to educate and inform its consumers. I realize those manufacturers probably disagree vehemently.


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## GranteedEV (Aug 8, 2010)

audioengineer said:


> I hope I've been clear that this excludes audio engineers and the small minority of hobbyists that successfully pursue a better understanding of objective measurements. This JBL speaker is aimed at the professional market. It's, IMHO, not a reference for what should be done in consumer audio.


So let me just clarify.

What should be done is that music/movies is produced on quantifiably accurate gear.
But when that music arrives at the end-user, it "just doesn't matter"?

I think that's a disservice to both the end user as well as the studio guy.



> o, let me correct myself and say the utility of specs is a continuum which depends on how good the specs are as well as the ability of the reader to interpret them. It is my experience that both are very low in practice, giving manufacturers and retailers fodder for misguiding consumers.


How does a manufacturer misguide consumers with specifications? Care to show a concise example? I see plenty of examples of manufacturers misguiding consumers with custom setups and specific demo discs, but i've never seen an example of your case. The closest thing I can think of is silly overbuilt products with designs that attempt to go beyond the realm of audibility... like the $60,000 YG Acoustics speakers I auditioned a few months ago, but the design did at least seem sensible regardless based on the measurements. At that price not something i'd seriously consider, but also not something trying to misguide a consumer.



> But, I do support any audio company's choice to publish a minimum of specs for the consumption of audio consumers because the majority of specs are either not useful or not interpreted correctly. And, "minimum" is smaller for HTIB than for individual components.


...and IMO it's this kind of professional attitude towards the end-user that gets people ending up with products from the likes of LG, Panasonic, Bose, Samsung, and Sony. And on forums like this, we seem to consistently get people disappointed by their purchases coming in for a second opinion and a much more informed purchase.


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## tesseract (Aug 9, 2010)

audioengineer said:


> All within the right context. My context of the consumer audio customer buying consumer audio equipment.
> 
> I hope I've been clear that this excludes audio engineers and the small minority of hobbyists that successfully pursue a better understanding of objective measurements. This JBL speaker is aimed at the professional market. It's, IMHO, not a reference for what should be done in consumer audio.


Absolutely incorrect, it is what we should be trying to achieve. I want to hear what the audio engineers making the recording heard. The picture GranteedEV posted of the Harman room looks much like a domestic home theater, to me. 


> So, let me correct myself and say the utility of specs is a continuum which depends on how good the specs are as well as the ability of the reader to interpret them. It is my experience that both are very low in practice, giving manufacturers and retailers fodder for misguiding consumers.


You do not educate a mushroom (general public) by keeping it in the dark. Then there are those of us who can interpret the data, find it very useful, and even consider it a selling point.

If a company is intentionally misleading consumers with embellished measurements, or no measurements at all, then they WILL be called on the carpet for it.


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## lcaillo (May 2, 2006)

audioengineer said:


> All within the right context. My context of the consumer audio customer buying consumer audio equipment.
> 
> I hope I've been clear that this excludes audio engineers and the small minority of hobbyists that successfully pursue a better understanding of objective measurements. This JBL speaker is aimed at the professional market. It's, IMHO, not a reference for what should be done in consumer audio.
> 
> ...


Context is very important, and I suggest you get to know the users that frequent this forum. Most of the regulars are not typical consumers. We go to great lengths to contextualize measurement, design, and opinion. Much of what you have written is correct, but much of it is out of context for the users here. 

The fact is that consumer product marketing decisions are made for reasons other than sound engineering and science. Bose, and others, publish the specifications that are in the best interest of their marketing plans. Some have been very successful in marketing their products. Once one recognizes that decisions to publish or not publish information is more about marketing than about engineering, it becomes easier to contextualize information or the lack of. 

Buying decisions are, for most consumers, much more about impressions and subjective assessments than objective evaluation. The typical user here is more interested in quantifying performance, and much more interested in the context of real room applications. That is largely why REW exists and, thus, why this forum exists.

Frankly, I think this thread has run its course and it would be far more useful to produce some reviews of actual performance of specific products in real application. Both subjective assessment and measurement are important, but debating generalizations where those in the discussion start with differing assumptions is becoming tiresome.


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## GranteedEV (Aug 8, 2010)

I was looking at this spec sheet for Ascend's new Sierra Tower (RAAL Tweeter version) :

http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend Sierra Ribbon Tower.pdf

And I really like how neatly laid out and understandable it is. Beyond the graphs there's some level of explanation as well as side-by-side comparision to its dome tweeter sibling.


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## phreak (Aug 16, 2010)

lcaillo said:


> Frankly, I think this thread has run its course


I have learned a lot from what I have read here. My basic philosophies surrounding my choices and biases have not been changed, but reading this thread has helped me understand the physics and marketing dynamics that have an impact on those preferences and biases. Please keep the info flowing.


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## lcaillo (May 2, 2006)

There has been much useful discussion, but some of the posts have gone beyond the limits of condescension and become too personal.

Home Theater Shack allows for discussions of controversial topics, allows for debate where users have very different opinions and perspectives, and welcomes respectful dialogue which is informative. If there is more to contribute on the matter of the value of audio specifications then more posting is welcome within the forum rules.


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## audioengineer (Feb 8, 2012)

lcaillo said:


> There has been much useful discussion, but some of the posts have gone beyond the limits of condescension and become too personal.
> 
> Home Theater Shack allows for discussions of controversial topics, allows for debate where users have very different opinions and perspectives, and welcomes respectful dialogue which is informative. If there is more to contribute on the matter of the value of audio specifications then more posting is welcome within the forum rules.



Lcaillo,
Right, Let's all get back to the high road. 

GranteeEd. I apologize. It's quite clear that the subjectivist (me) and objectivist (you) are not going to come together on the value of the audio specs the average consumer finds when he/she goes shopping for consumer audio equipment. 

Let me leave you with a couple of things.
First, although he's a fairly bipolar figure, I urge you to read John Atkinson's AES papers. He had made a long, and serious go at trying to figure out how measurements can help him distinguish between the good and great. I've known John for a long time, and despite the fact that he's not an audio engineer, he's got a good head on those shoulders. 

Second, there's a silver lining for everyone: 30 years ago the chances of walking into a hifi store, randomly picking a system, and getting something with good sound was pretty low. Today, thanks to contributions from many individuals and companies, lots of good basic audio engineering principles have become commodity ... making a surprisingly high % of audio systems available today decent. 



So, where to from here. How about listening skills? Becoming a good enough listener to judge accuracy of reproduction, accuracy being distinctly different from preference, is not easy IMHO. In my experience, it's common for people get the two mixed up. What're your thoughts on what it takes to subjectively judge accuracy? How do you define accuracy when most of the recording chain starts out with directional information, all that is largely thrown away beginning with the mic feed, and yet we use 3-dimensional devices (speakers) to reproduce?


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## gdstupak (Jul 13, 2010)

Listening for quality in equipment is something that can be learned (listening for noise, jitter, clipping...).
Listening for reproduction accuracy is something much harder to come by. Before you can judge reproduction accuracy, you have to have listening material that you know how it should sound (not how you would like it to sound). So before going out and testing new speakers, you have to have listening material that you are completely familiar with through a rig that has been proven to be highly accurate, something most of us don't have available to us. Sure, you could travel to some exotic shop that has a $10,000 rig which sounds uber wonderful, but that doesn't mean it is accurate.
The most common advice given is for people to test equipment using material that they know well. So, what is actually being taught is that people should buy equipment that sounded good and familiar to them, the common person would have no idea whether any of it was accurate.


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## audioengineer (Feb 8, 2012)

gdstupak said:


> Listening for quality in equipment is something that can be learned (listening for noise, jitter, clipping...).
> Listening for reproduction accuracy is something much harder to come by. Before you can judge reproduction accuracy, you have to have listening material that you know how it should sound (not how you would like it to sound). So before going out and testing new speakers, you have to have listening material that you are completely familiar with through a rig that has been proven to be highly accurate, something most of us don't have available to us. Sure, you could travel to some exotic shop that has a $10,000 rig which sounds uber wonderful, but that doesn't mean it is accurate.
> The most common advice given is for people to test equipment using material that they know well. So, what is actually being taught is that people should buy equipment that sounded good and familiar to them, the common person would have no idea whether any of it was accurate.



Well said, couldn't agree more. 
Access to making your own recordings and to professional studios is very helpful.
That's why I have respect for JA. He gets out there and does it.


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## audioengineer (Feb 8, 2012)

And,

Start w something like Dave Moultons ear training course. Most people find their threshold for reliably detecting deviations falls between 6 and 9 dB for a third oct band. Pretty sobering for many a self professed audio professional. I was in that boat until I made the commitment to take it seriously, study, and regularly practice.

This will make any time you spend in the studio much more valuable.

There are also good books on the topic via Amazon for reasonable money ... Though I like David's because it's backed up by his demonstrated proficiency in the field.


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