# Buy Calibrated or not?



## audiomike (Oct 7, 2011)

Hey guys, new to this but I am starting to build my measurement system. I was looking at buying a ECM8000 but I found a few places that sell ECM8000's that are calibrated and come with a disk with the file.
Is there large gains to be had by spending the extra money to get a calibrated mic, can the file be used?

One last question, do you even need a mic at all or can use just use a RS SPL Meter?

I have been doing my reading of the available info and I still have quite a bit more info to read on the various subjects but I am still unsure on these points.

Thanks for your help.


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## Kal Rubinson (Aug 3, 2006)

audiomike said:


> Hey guys, new to this but I am starting to build my measurement system. I was looking at buying a ECM8000 but I found a few places that sell ECM8000's that are calibrated and come with a disk with the file.
> Is there large gains to be had by spending the extra money to get a calibrated mic, can the file be used?
> 
> One last question, do you even need a mic at all or can use just use a RS SPL Meter?
> ...


You can use the RS SLM but it is not calibrated (except generically). OTOH, I would not bother with buying a non-calibrated mic for measurements which are only as good as the data they are based on.


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## audiomike (Oct 7, 2011)

Kal Rubinson said:


> You can use the RS SLM but it is not calibrated (except generically). OTOH, I would not bother with buying a non-calibrated mic for measurements which are only as good as the data they are based on.


So what is your suggestion, to go with a SLM or a calibrated mic?
Which would give the most accurate measurements?

I am new to this whole idea of measuring my system with REW and using an external unit to adjust it.

I am just not sure what I need to pick up to get started in this whole area.

I appreciate your help.


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## Alex2507 (May 10, 2008)

First of all I don't know how to use REW. However some time ago I bought a calibrated mic in hopes of one day figuring it out. I thought I would want my measurements as accurate as possible. The RS SPL meter for me is what I use to level match my speakers.


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## Kal Rubinson (Aug 3, 2006)

audiomike said:


> So what is your suggestion, to go with a SLM or a calibrated mic?
> Which would give the most accurate measurements?


Calibrated mic, of course.



> I am new to this whole idea of measuring my system with REW and using an external unit to adjust it.
> 
> I am just not sure what I need to pick up to get started in this whole area.
> 
> I appreciate your help.


Isn't there a thread here on REW?


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## Gorilla83 (Sep 21, 2011)

I'm also interested in the 'need' for calibration. I too already own a RS "new" SPL meter and would be using this for sub calibration only - so likely 15hz to 100hz. Within this range is it worthwhile to invest in a calibrated mic?

After looking a the mic comparision results in this thread (below), it seems the RS would suffice for my application but wanted to get some other opinions. 

http://www.hometheatershack.com/for...d-cards/6797-behringer-ecm8000-sms-1-mic.html


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## SAC (Dec 3, 2009)

I know folks seem to think that since they are 'only looking at the LF extreme' that they do not need to invest in decent equipment, but the fact is, below 30 Hz, ANY results you get are suspect unless you invest in a good pre-amp and a good mic as the phase and accuracy of the frequency response below ~30 Hz WILL be inaccurate. You are simply reaching into a critical response region whereupon, you get what you pay for. There is no free lunch.



I will also add that it is, in my opinion, truly a shame that folks assemble the test equipment sufficient to actually measure, analyze and fully treat a room, and quite just after the ONLY EQ a sub, which is considered a pre-requisite to actually tuning a room, where the specular behavior above the modal region actually determines the imaging, localization, tonality and intelligibility of the speaker-room interaction!

To think that folks have finally been provided with the means to examine the specular realm in atomistic detail (not to mention the power it gives them to similarly analyze their speakers themselves - an act that would probably scare the pants off many brave enough to do it to see what is REALLY happening!)and then to have them simply stop is the height of irony!

But hey, to each their own. But its discouraging to see so many get SO close, and to simply stop.

The strange thing is that most balk at the purchase of their equipment all the while they have no qualms about purchasing mystical cables and EQs, etc., that costs even more, when the effectiveness of much of that gear (eg: the EQ) is limited precisely by the measurements used to determine the setting! Not to mention that the full tuning of the speaker-room interaction will provide an magnitude of increase in sound quality that _far exceeds_ the differences that so many obsess over in choosing to spend a few hundreds dollars more on receivers, AD/DA converters, DVD players, etc! A bit more awareness into the actual cost benefit analysis of room acoustics - and no folks, this is not achieved by Audyssey, et al, as EQ simply does not solve the dominant non-minimum phase errors present in the specular region, would actually be money well spent where the reasonably small investment is ACTUALLY recovered in REAL perceived improvements in sonic quality.

But hey, despite the accuracy of what I have said, I fully expect a raft of folks to respond calling for the pitchforks and torches and witch burnings. So be it...

My suggestion, if you are interested in examining either the lowest octave or two and a full range response, do a bit of research and at least buy a decent 2 channel pre-amp and mic. If not, you can feel secure in the knowledge that you tried, but don't believe that you actually achieved the degree of success that you might have had the measured response been more accurate. And if you get really brave, you just might want to investigate the next step which can bring an even more dramatic improvement in the listening quality and you will have a platform capable of doing it. And if nothing else, you can easily resell the pre-amp and mic to others who would like to do this if you think you have no further use for it.

------------------------

Oh, and please don't simply start posting demands that I research every low end pre-amp to determine which actually have acceptable performance. That's not my job. I have already invested in such equipment with verifiable performance. An example of which is provided above. Its part of your due diligence to investigate and ask for real objectively verifiable specs and not to simply look for the cheapest unit you can find. (Nor is the goal to go wild and buy the most expensive unit either!) Its not hard, and it is no less a responsibility than what most do for any other piece of gear. But in this case (unlike with speakers where you get meaningless anechoic frequency response and no information on various actual spatial loading configuration responses and actual vertical and horizontal Q/dispersion data or impulse/ETC responses), demand evidence of the frequency response and phase linearity in the response regions of concern...


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## Alex2507 (May 10, 2008)

SAC said:


> Oh, and please don't simply start posting demands that I research every low end pre-amp to determine which actually have acceptable performance.


I'm not demanding that you research every low end pre-amp ... just the Behringer Xenyx 802. I don't know if you caught it in my earlier post but I mentioned that I don't know how to use this with REW yet. I just thought I would ask your opinion if you have one on this often recommended pre-amp. I actually had to dig the unit out and verify that it was a pre-amp. I thought it was just called a mixing board. Yes, I don't know my elbow from a hole in the ground when it comes to this.


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## SAC (Dec 3, 2009)

Most are fine for general purpose use. 

The unit's mic input is rated in the manual as being 20Hz -20kHz. And I suspect that that is fine within the tolerances stated (or rather unstated, as they provide no mic spec tolerances and no phase specs at all!). And to be fair, for an integrated mixer and multi-input pre-amp for ~$50 while many dedicated pre-amps costing several times more exhibit specs similar to those posted in the earlier thread posted above, the performance probably shouldn't be expected to exceed them.

For general use it will probably be fine. The problem arises when folks expect to analyze performance down to DC, or in at least one other stated case, 5 Hz. Below about 30 Hz is questionable in all but the best units, and you want to know the phase error in addition to simply the frequency response. If folks are expecting the ability to more precisely analyze below about 30 Hz and/or above about 6-8 kHz, one will want to further investigate the actual measured performance of the pre-amp and mic performance.

Thus, in that regard, a low end pre-amp and the use of an large capsule SPL meter with a generic correction curve is a 'bit' limited. 

Again, the main thing is to recognize the limits of your tools, and to recognize their limits and when they do not provide an accurate basis for actions.


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## Alex2507 (May 10, 2008)

SAC said:


> ... the main thing is to recognize the limits of your tools, and to recognize their limits and when they do not provide an accurate basis for actions.


Thanks for the reply. It's good to know what my equipment is good for >30Hz - <6-8KHz. Eventually I'll get around to using it ... it's only been a couple of years since I bought it. I tell people all the time that I may be slow but I get there.


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## SAC (Dec 3, 2009)

OK, now that I have apparently scared a few folks, let me also point out the bright side!

While many of the least expensive pre-amps are not really suitable for below ~30 Hz operation (nor were they ever really designed for that purpose as, well, face it, real world recording is not generally focused on that bandpass... 

They are fine for the larger realm of operation that includes the predominate region of LF modal behavior as well as the critical ranges of the specular region 'above' the modal region. 

A region which, quite frankly, more would greatly benefit from becoming aware and taking advantage of the tools at your disposal!

So rather than shelving the idea, I would recommend expanding your vision to include addressing the time domain response of your system and reducing the anomalous indirect high gain reflection issues with techniques other than simply EQ! (Note: EQ is NOT effective for these issues!)

At this point you will shift your thinking from frequency to arrival time and gain, and all treatments will be 'broadband', meaning that it is effective from ~300 Hz and up, with the low frequency extension of the employed treatments proving to be the challenge, while the high frequency mitigation is 'easy'. 

The point of such treatment is to address the full spectrum of the specular energy and not to color the resultant reflections and the environment with effectively EQs reflections due to treatments acting as low pass filters that remove only the upper mids and highs while ignoring the higher energy content mids and lower mids. And for the most part this means utilizing the proper materials at the proper thicknesses and gaps to accomplish sufficient bandwidth coverage for absorption as well as properly designed and adequate diffusion techniques as well that do not only address the easily mitigated short wavelengths of the relatively low energy higher frequencies.

So you have the measurement tools for measurement, easily adequate to address fundamental modes and to employ porous or tuned resonators for modal behavior as well as the ability to expand your horizons and to measure and conduct an analysis of specular behavior along with the ability to identify and analyze reflections for their paths and points of boundary incidence...So now the challenge becomes to build and employ treatments that are adequate to the task! (If its not one thing, its another!!!)


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## coolkish (Apr 12, 2011)

Hi SAC,

From the pic you posted which one was more 'accurate' and what mic/pre combo do you use and others you recommend? I have seen most common being calibrated ecm8000+m-audio or xenyx pre. I know of another audiophile who recommends only earthworks mic (he criticized me for having over $9K in gear but questioned my hesitation to buy $500+ miclddude 

Thanks


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## SAC (Dec 3, 2009)

coolkish said:


> Hi SAC,
> 
> From the pic you posted which one was more 'accurate' and what mic/pre combo do you use and others you recommend? I have seen most common being calibrated ecm8000+m-audio or xenyx pre. I know of another audiophile who recommends only earthworks mic (he criticized me for having over $9K in gear but questioned my hesitation to buy $500+ miclddude
> 
> Thanks


Which one is more accurate? The one with the linear magnitude and phase response as opposed to the one with the roiled off low frequency response and phase deviation. Not to mention a significantly reduced noise floor! 

'Only' Earthworks mics? They are good medium range mics (~$600-650; 9Hz-30kHz) , but they are not the only mics on the market by any means. That said they represent an excellent balance between quality and esoterica that one is afraid top take out of a lab and expose to being dropped or encounters with the dreaded wanton chair carts.

But as you provide no reference to what exactly you are doing , or will do in the future with the gear, I am left with exploring the countless combination and permutations possible.

So....what are you measuring? It could be practical or it could indeed be folly. (The same assessment can be made of the dear itself!)

The 'right' gear is that which affords accuracy that adequately complements your goals and needed precision. And it is not unusual to find folks trying to make adjustments that are more precise than their equipment. For example, if your gear is accurate +-3 dB, it is rather silly to think that you are accurately making adjustments to the nearest 1-2 dB! Just as if you only have a measuring stick precise to the nearest foot, it is unreasonable to to expect your measurements to be accurate to more than the nearest estimated 1/10th of that unit. And any calculations made with said measurements are never more accurate than the least precise variable. Unfortunately this fact is commonly violated in SO many derived quantities used for evaluation.

So one needs to be aware of the fundamental limitations of the equipment and to not assume a greater degree of accuracy than is warranted.

Thus, as far as 'calibrated' mics, I guess that I would say that the greater the variability in a unit model, the more the need for calibration. But one should NOT mistake such calibration as somehow increasing the precision of the piece of equipment!!! Such calibration doe not reduce the degree of variance (lack of precision) in the piece of gear! While providing a baseline for comparison, the degree of variance is still an integral function of the unit.

So, in my opinion, a RS SPL meter may be suitable for setting gross comparative levels, but it is not a reference level - it simply provides a means to compare different sources to a common reference. And such a unit is not suitable for anything but 'gross' low frequency magnitude measurements. And your measurements will never be more accurate than its limitations.

A basic mic is a good buy insofar as its not a huge loss if you drop it (ouch!) and if you only need general relative measurements.

Beyond that, one must ask what they are measuring and trying to accomplish and what degree of precision and accuracy is required. There are MANY legitimate applications and reasons that require the investment in more accurate and precise tools. There are also some that do not require such an investment.

I get the feeling that you are asking me exactly what degree of precision is required for your application based on the investment in equipment, and unfortunately that has little correlation. Just like a car, you can spend $10k on a vehicle or $100k on a vehicle, and the cost of a tool required to do a job is not based upon the cost of the car, but upon the degree of precision required for a particular adjustment. A simple wrench may suffice or a precision torque wrench may be required. 

So we have a choice. We can either assume that someone will only be making very gross adjustments, or we can assume that they will encounter adjustments that require a higher degree of precision. On e route takes you down a road where your tools are not adequate for the job in many instances, and the other affords you tools capable of greater precision but which may exceed the requirements for many simple gross settings.

While the latter costs more, at least your tools provide the accuracy necessary in all cases, while in the former, your tools allow for not more than a guesstimate a portion of the time. Personally, I prefer to error on the side of greater accuracy rather than a simple _belief_ that my effort made a difference and that they displayed 'some number' regardless of how accurate it might be.

This is further complicated in so far as some provide services for other parties who pay for such services. Some do it only as a hobby and thus only impact themselves. 

So, bottom-line, there are many variables involved. Simply buying the 'cheapest' may work in some circumstances, or it may not be the best investment. But in any case, there are a few additional factors that determine if the best investment is a Toyota Corolla, a full-sized pickup truck or a Porsche GT3, based upon their intended use.

As far as what I use, (note this goes beyond basic applications), I have 3 primary pre-amps - an Easera Gateway, suitable for use with the TDS module with integrated loopback, a Duran Audio Axys, for use with programs such as ARTA and Easera, and 2 ganged PreSonus FireStudio Projects (8 channels) for multi-channel measurements with platforms such as Easera Pro. While the Gateway and Axys are similar and both feature an internal loopback (allowing 2 channel FFT measurements), while the Axys has superior linearity and noise floor (and works especially well with accelerometers).One could easily make due with just the Duran Axys instead of both the Gateway and Axys. But hey, I had the Gateway and 'upgraded'. ...Those are in addition to a variety of other proprietary front ends such as TEF.

A few pre-amp characteristics are worth looking for: a metal case, 48v phantom power, balanced I/O - especially XLR, If TRS, MAKE SURE the jack is secured with chassis secured nuts - as jacks simply mounted on circuit boards tear up QUICKLY - as circuit boards are not effective strain relief!
Also, some units feature external knobs and others use software controls. Knobs are convenient but have a way of becoming damaged in transit...but I will leave that to your preference.

As far as mics, they vary depending upon use. But generally, there are two important qualities: omni-directivity and a physically small capsule allowing for extended high frequency accuracy and precision.
For serious work it is common to have 2 types of mic. One type for general field use and another type for more precise use. One suggestion is (a matched pair) such as the Audix TR-40A (~$200), which has been replaced by the Audix TM1 (~$299), at the low end, and a high quality precision mic like the DPA 4007 ($1700) at the high end.

Additionally you may find a variety of additional (matched) mics useful for multi-channel measurement use ranging from distributed live use (with a program like SysTune), or for simultaneous speaker polar measurements (being about to sample 12-18 samples at a time sure beats the hassle of repeating such measurements 30+ times!) as well as accelerometers to measure the resonance of boundary surfaces, doors, windows, and speaker cabinets.

BTW, Parts Express has the Dayton EMM6 on sale for less that $40 till the end of the year. And while I have not personally used it, the Beyer MM1 for about $169 through B&H seems like it could be a good deal for the precision...


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## aackthpt (Jan 24, 2011)

I think the dayton emm-6 suffices for most enthusiasts purposes and it is provably more consistent than the behringer mic. If you are only going to measure down to 20 Hz just get it from dayton. If you want to be able to measure to 10 hz with accuracy then get the calibrated one from CSL (user anechoic here) on which I believe you can find an ongoing discount for shack members. There is a diy option out there that works fine below ~500 hz, look for the lilmike mic thread on avs. There is a good thread comparing many of these options (i think on avs).

I think any mic option is much more accurate and repeatable than any SPL meter approach. The only reason to go with the SPL meter approach is if on an extremely limited budget.

Preamps matter less as the response gets removed in REW. A small mixer can work fine if using a desktop machine, though I think it is always good to use an outboard sound card like a behringer uca unit. An integrated way to do it all is something like the m-audio mobilepre usb or for a small step up a tascam us-122 or 144. The Lexicon Alpha might be an option too, though you should be looking for a 2+ channel unit so you can use loopback once you are versed in use of the software.


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## SAC (Dec 3, 2009)

aackthpt said:


> Preamps matter less as the response gets removed in REW.


The input is the 'sum' of both mic and pre-amp. Either can be the limiting factor, and the processing will be no better than the source signal provided to it. And BOTH must be of sufficient accuracy, precision, and bandwidth with respect to the intended use. Thus the mic and pre-amp define the quality of the results for all practical purposes. Thus it makes no sense to spend much on one, if the quality of the other is not commensurate, as the total response will be limited to the weakest link in the signal chain.

If only it were a valid contest to see what is the absolutely cheapest option regardless of accuracy, precision. bandwidth and intended use!


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## aackthpt (Jan 24, 2011)

SAC said:


> If only it were a valid contest to see what is the absolutely cheapest option regardless of accuracy, precision. bandwidth and intended use!


:T Actually, I really enjoy finding the least expensive option that meets the requirements of the intended use, and that goes for the entire chain not just audio measurement.

My experience, having been completely new to this a year or so ago (and without previous recording experience), was that current information on the best equipment options for a simple measuring system was difficult to find. Further, it took putting together a measuring system and gaining some experience with it before I fully understood it and thus had much clue how to run it effectively - probably a dozen sessions with REW getting used to setting levels, understanding gain on the input vs. output sides, etc before really understanding what I was doing - and that's regardless of having read the entire REW manual. From that standpoint, for most people who are asking basic questions, I think a really good answer to the puzzle is "buy the least expensive reasonably good thing" (preferably a bit past current capabilities giving you something to grow into) as once you gain a working understanding you reach a better position to make those decisions oneself.

It would have helped immeasurably for there to have been a sticky linked from the REW download pages or somewhere with a maintained "good/better/best performance" or "low/med/high cost" or "novice/intermediate/expert" recommendation for an REW equipment chain.


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## KalaniP (Dec 17, 2008)

aackthpt said:


> :T Actually, I really enjoy finding the least expensive option that meets the requirements of the intended use, and that goes for the entire chain not just audio measurement.
> 
> My experience, having been completely new to this a year or so ago (and without previous recording experience), was that current information on the best equipment options for a simple measuring system was difficult to find. Further, it took putting together a measuring system and gaining some experience with it before I fully understood it and thus had much clue how to run it effectively - probably a dozen sessions with REW getting used to setting levels, understanding gain on the input vs. output sides, etc before really understanding what I was doing - and that's regardless of having read the entire REW manual. From that standpoint, for most people who are asking basic questions, I think a really good answer to the puzzle is "buy the least expensive reasonably good thing" (preferably a bit past current capabilities giving you something to grow into) as once you gain a working understanding you reach a better position to make those decisions oneself.
> 
> It would have helped immeasurably for there to have been a sticky linked from the REW download pages or somewhere with a maintained "good/better/best performance" or "low/med/high cost" or "novice/intermediate/expert" recommendation for an REW equipment chain.


Word. 

(The stickies do, of course, make a few recommendations, but SAC seems pretty down on those options, which is a bit discouraging.)


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## Wayne A. Pflughaupt (Apr 13, 2006)

KalaniP said:


> (The stickies do, of course, make a few recommendations, but SAC seems pretty down on those options, which is a bit discouraging.)


Not to worry. It’s one thing if you’re a pro (i.e. making a living at doing this), but the hardware recommendations in the stickies work fine for the casual user; scroll through the dozens of pages of old threads from happy customers if you doubt.  

Regards,
Wayne


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## KalaniP (Dec 17, 2008)

Wayne A. Pflughaupt said:


> Not to worry. It’s one thing if you’re a pro (i.e. making a living at doing this), but the hardware recommendations in the stickies work fine for the casual user; scroll through the dozens of pages of old threads from happy customers if you doubt.
> 
> Regards,
> Wayne


If I doubted that much, I wouldn't have placed my orders. 

It's still more than a little discouraging to see your new toys disparaged in every third post from SAC, who clearly knows a lot about the matter. :doh:


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## SAC (Dec 3, 2009)

KalaniP said:


> Word.
> 
> (The stickies do, of course, make a few recommendations, but SAC seems pretty down on those options, which is a bit discouraging.)


Have you actually read anything I have written?

I have repeatedly suggested a number of _low cost_ solutions that _actually work_ (go figure), the least expensive of which is the ART Dual USB Pre that can be had for $69 - as opposed to the myriad threads that KEEP trying the SAME cheap Behringer and Sound Blaster devices that for a variety or reasons neither work nor perform to the level many want them to perform.

And the _recommended_ inexpensive solutions work fine for moat of the applications - but with the caveat that they DO have limitations - for which operators need to be aware! ...which many simply ignore.

So if folks want to keep trying to make cards work that are variously: not supported by various OS'e, or lacking 2 channels, or and balanced inputs, or phantom power... be my guest. 

And there is NO NEED to repeatedly do this! Besides, they get a bit old when we have 2-3 threads pertaining to these exact problems going at any time!

And if you expect higher levels of performance that exceed the capabilities of the basic IO gear, such a sub 20 Hz or extended HF performance, you can either delude yourself by ignoring the specs and simply reading plots assuming they actually correlate to reality, or you can invest in the gear necessary to properly evaluate the response to the extended degree of performance necessary.

Its your choice.

But I'd appreciate it if you would stop misrepresenting what I have said as my being categorically against all inexpensive solutions!


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## KalaniP (Dec 17, 2008)

SAC said:


> Have you actually read anything I have written?
> 
> I have repeatedly suggested a number of _low cost_ solutions that _actually work_ (go figure), the least expensive of which is the ART Dual USB Pre that can be had for $69 - as opposed to the myriad threads that KEEP trying the SAME cheap Behringer and Sound Blaster devices that for a variety or reasons neither work nor perform to the level many want them to perform.
> 
> ...


I've read nearly all of your posts, actually (for the past couple months), and read every word of them. Would you like me to quote for you the various things you've said, for reference? I'll do so below. If you're going to accuse me of misrepresenting something, please do so accurately. What I said above is that "The stickies do, of course, make a few recommendations, but SAC seems pretty down on those options".

The setup most readily identified in the stickied FAQ is the Radio Shack SPL meter with the SoundBlaster USB card (or similar, or a long-discontinued Turtle Beach card), or the Behringer 502 mixer/preamp with a Behringer ECM8000 mic (or Dayton EMM-6). In the past few weeks I've lost count of how many times you've slammed each of those as being noisy, inaccurate, and basically undesirable for all but the most casual user (and even there only within a very restricted range) who would basically be imprudent to use it rather than spending more on what you deem to be a more capable setup. The "_low cost_ solutions that _actually work_ (go figure)" are NOT cited in the FAQ, which is where most logical people are going to go for their initial information.

In case you think this is all in my head, here is a small sampling of threads just from the past week or so where you've been quite down on the "usual" list of gear (hiding this in spoiler tags simply to enhance readability and not make this post quite so crazy long):


*Spoiler* 



http://www.hometheatershack.com/forums/rew-forum/51389-recommendations-hardware.html#post469510:


SAC said:


> Why, at ~$49 I suspect the 502's pre-amps are absolutely world class. :rofl2:
> 
> But then I am not sure exactly how the additional functions provided by a mixer would be beneficial for that function anyway considering that REW is limited in its ability to process multi-channel measurements.
> 
> ...





SAC said:


> So out of the above you come away with the idea that the Soundblaster is somehow appropriate?
> 
> As it readily accepts a mic input and supplies phantom power????
> 
> ...





SAC said:


> I proposed a 502 ONLY because you said you needed a 'mixer' and because that was already suggested in the REW interconnect diagrams.
> I also then described the 502's pre-amps as about as cheap as can be sourced, as well as questioned the need for a mixer.
> 
> I (and others) have repeatedly suggested a decent 2 channel pre-amp with phantom power that is configured to accept i mic input, the cheapest being the ART USB Dual Pre. But that is by no means the only pre-amp featuring that particular topology.


http://www.hometheatershack.com/for...in-7-64-bit-family-room-setup.html#post469470



SAC said:


> Just a few comments.
> 
> Various mics do indeed have an optimal orientation with regard to the target where their phase linearity and frequency response is optimized. This orientation is normally specified by the manufacturer. And 90 degrees perpendicular is indeed a common optimal orientation. An example of this is the Earthworks M30.
> 
> ...


http://www.hometheatershack.com/for...-how-measure-rooms-accoustics.html#post461573



SAC said:


> Asking what is necessary to measure room acoustics is a rather vague question.
> 
> And from the remaining responses, it seems that most consider only the ability to measure frequency response and SPL levels to be sufficient.
> 
> ...


http://www.hometheatershack.com/for...lp-setting-up-ecm-8000-please.html#post461357



SAC said:


> You aren't likely to contact anyone at Behringer intimate with the actual design of the gear!
> 
> Thus the larger issue becomes one of just what it is exactly that you are looking for regarding "how to set this thing up".
> 
> ...







I do agree with you that there are MANY threads asking the same sorts of questions over and over, but I rather suspect that the source for many of those questions is the FAQ, which many prudent take the time to read, and perhaps buy gear based on the discussion they find linked therein, only to have said gear denigrated by you when they start to ask questions.

I can't help you with people who DON'T read the information offered in the FAQ, or misinterpret it, or buy hardware that in not appropriate for their personal computer setup (PC-only hardware for a Mac, Mac-only hardware for a PC, outdated hardware with no drivers for their current OS, etc.), without doing the smallest amount of homework to check based system reqs listed for said hardware, well, that's their own fault, and no one can protect all of us (including you) from that sort of end-user carelessness and the wasteful threads that result therefrom.

If you would like to confer with the author of REW and/or HTS mods, perhaps the FAQ could be updated to include a number of recommended hardware options that YOU deem acceptable, and remove references to the gear that you find so objectionable/limited (or at least make and addendum to them stating their precise limitations and offering better solutions in their place). That would be useful information for many people seeking to dip their toes in the water.

But please don't deny that the majority of your posted recommendations and answers to questions regarding startup hardware (other posts in other sorts of threads do not necessarily fall under this umbrella), while likely factually correct and containing useful information, are indeed quite negative. It only took me a few minutes to assemble the examples above... perhaps you just don't realize the overall negative tone your posts take, especially cumulatively? I can't speak to long term patterns, just what I've seen over the past month or so that I've been reading this board heavily.

Please understand that I appreciate your obvious knowledge and deep understanding of the subject matter, but the near-constant negativity and acerbic tone does grate from time to time. It makes it harder to appreciate the valuable knowledge that you are freely imparting.


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## SAC (Dec 3, 2009)

LOL!

What's wrong? Are you upset that my comments about the gear commented upon all are below the performance capabilities and precessing levels presented by the least expensive alternatively mentioned ART Dual USB Pre available for all of an exorbitant $69 - and that it works with both Mac and PC? Not to mention issues with compatibility and the myriad adapters required to gerrymander the system together?

And each time folks opt for the 'cheaper' solution that costs them more in terms of time, aggravation, and often money as they have trouble gerrymandering their chosen options together or discover that it doesn't work at all. 

And then too often their goal is to do something that is beyond the accuracy of the chosen configuration to do accurately.....What a bargain!
But you are right! We should just smile and let them delude themselves into thinking that because they equipment outputs a graph, that the data is accurate!

OK, if it will make you feel better, you have my blessing to opt for incompatible and or lower performing options about which you can come and complain that we have not warned 'you' and of how unfair it is that your whiz bang bargain basement system is either inaccurate for many options or utterly incapable of making many measurements despite costing MUCH more (as with the anything but) 'Omni"Mic.

Funny, when I recommend against such gear, that is negative. But when the myriad folks who persist in buying the same stuff only to repeatedly post that they are having trouble configuring it or getting it to work, that is apparently wonderful. So, in keeping with your preferences, when folks do that, we will simply congratulate them on a prudent choice well made.

....Now how do I interface the Behringer or Dayton mic with the Soundblaster or Behringer U202???? And why do I need a 2 channel preamp with phantom power? ...I _just_ want to EQ my sub down to 5 Hz!.....


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## KalaniP (Dec 17, 2008)

Forest for the trees. I'm sorry, you appear to have completely missed my point.

So be it.


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## aackthpt (Jan 24, 2011)

SAC said:


> ....Now how do I interface the Behringer or Dayton mic with the Soundblaster or Behringer U202???? And why do I need a 2 channel preamp with phantom power? ...I _just_ want to EQ my sub down to 5 Hz!.....


Exactly why we need an improved startup equipment FAQ. The recommendations that the mixer can be used are never stated in the same place as "you need the UCA202 to interface it with your computer.... especially if it only has mic-in" or even "you can adapt between RCA, 1/4 TS (with the noob going WTF is TS??), and 1/8 TS(TRS with appropriate care)" or even "those funny connectors on the ART Pre take 1/4 TS as well as XLR". To those without recording experience, the idea that you actually need an audio interface and mic pre (with phantom power, with possible use of external phantom power leading to a third confusing component) that might or might not be in one box depending on how you go about it, can be confusing. Before I started in on this, my main contact with microphones was on computers where (in the consumer sector) they all have TS connectors. I'd been connecting consumer electronics since I was 7 years old, but this was a whole other world - one for which the process of procuring gear and learning REW was a great introduction.

When I was first looking to get set up for REW, I contacted a well-known online acoustics personality for advice, and the suggestion for a pre was a piece of gear that wasn't even in production anymore, making it even difficult to find on the manufacturer's website! Especially when the common name is not the complete name... talk about confusing. In the end I did opt for that unit as I found an inexpensive refurb on eBay, but the process sure was not efficient.

Now that I look (and understand what I'm looking at), brucek's cabling & connection sticky is pretty complete. I think it's an excellent guide to getting things hooked up - however since it only covers use of SPL meter as mic (which I figured would be pretty compared to a real mic) and use of a mixer (which I see both as overkill and fraught with potential for n00b error due to the features beyond a simple two channel pre), I think it leaves something to be desired in terms of equipment suggestions - especially to the confused n00b not looking to wade through four pages to sift out equipment possibilities.

Also, strangely while there are links to the top of the forum from the REW download page, there aren't links to the REW area or to the "SPL Meters | Mic's | Calibration | Sound Cards" area where I would not necessarily have thought to look for equipment suggestions as a n00b. I understand that it's a lot of information to manage, but having everything scattered around sure didn't help initially.

I'd gladly author and maintain such an equipment-only FAQ (and would certainly consult you SAC for advice on the limitations and higher end gear) if it could be arranged and the mods think it would be a valuable addition. If such could be linked from the REW homepage it would be icing! :T:bigsmile::clap:


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## KalaniP (Dec 17, 2008)

aackthpt - Thank you. Well put.


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## Wayne A. Pflughaupt (Apr 13, 2006)

SAC said:


> ...you have my blessing to opt for incompatible and or lower performing options that we have not warned 'you' and of how unfair it is that your whiz bang bargain basement system...
> 
> Funny, when I recommend against such gear, that is negative. But when the myriad folks who persist in buying the same stuff only to repeatedly post that they are having trouble configuring it or getting it to work, that is apparently wonderful.....


The price of the equipment has no bearing on any problems configuring or getting it to work with REW. We’ve had plenty of people come through here with high-priced gear that they couldn’t get to work.

Regards,
Wayne


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## Wayne A. Pflughaupt (Apr 13, 2006)

aackthpt said:


> Now that I look (and understand what I'm looking at), brucek's cabling & connection sticky is pretty complete. I think it's an excellent guide to getting things hooked up - however since it only covers use of SPL meter as mic (which I figured would be pretty compared to a real mic) and use of a mixer (which I see both as overkill and fraught with potential for n00b error due to the features beyond a simple two channel pre)...


brucek’s REW Cabling and Connection Basics guide covers more than just using the SPL meter as the mic. It also covers using an “upgraded” condenser mic with a standard computer sound card/separate mixer-pre-amp combo, or an “all in one” pre amp/sound card.




> Also, strangely while there are links to the top of the forum from the REW download page, there aren't links to the REW area or to the "SPL Meters | Mic's | Calibration | Sound Cards" area where I would not necessarily have thought to look for equipment suggestions as a n00b. I understand that it's a lot of information to manage, but having everything scattered around sure didn't help initially.


Nor sure I follow you there. Are you saying the REW icon at the top of the Forums page, which opens up the “REW – Room EQ Wizard Home Page,” should include links to the REW Forum and Mics/Meters/Calibration/Soundcards Forums? 

It used to be that the “Equalization/Calibration” area (that includes the REW, BFD, Soundcards and Downloads Forums) was at the very top of the main Forums page (i.e. where the “General Shack” area is now). Do you feel that would be better – less confusing - than having to scroll down the page to find the “Equalization/Calibration” Forums? (Personally I thought it was a mistake to move it down to where it is now, seeing that REW is the Shack’s “claim to fame” as it were.)




> ...I think it leaves something to be desired in terms of equipment suggestions - especially to the confused n00b not looking to wade through four pages to sift out equipment possibilities.





> I'd gladly author and maintain such an equipment-only FAQ... if it could be arranged and the mods think it would be a valuable addition.


It’s a great idea, but I’m not sure how practical it is. For starters, there’s just too much stuff on the market, especially sound card options, for anyone to practically evaluate. And one that works great for one operating system often doesn't do so good with another. Then you have the PC/Mac thing...

Of course you could compile a list by trudging through five years of our existing threads to find out what others have used. 

But the problem is that new gear is always coming out, and old gear discontinued (as you found out yourself when you were trying to acquire your equipment). So today’s “Recommended Equipment” list is obsolete and/or incomplete at some point down the road.

In the end - trust me on this - no matter what equipment is “recommended” there will be no shortage of people inquiring about using something else, often something they already have on hand.




> ...(and would certainly consult you SAC for advice on the limitations and higher end gear)


The beauty of REW is that it doesn’t require expensive equipment. We've seen a lot of talk, but no one has offered any proof that they got better results using high-priced sound cards and mics. "Proof" would be an A/B comparison.

Regards,
Wayne


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## aackthpt (Jan 24, 2011)

Wayne A. Pflughaupt said:


> brucek’s REW Cabling and Connection Basics guide covers more than just using the SPL meter as the mic. It also covers using an “upgraded” condenser mic with a standard computer sound card/separate mixer-pre-amp combo, or an “all in one” pre amp/sound card.
> 
> 
> > You're right. I didn't review it carefully. Interesting to note, though, that in the "integrated pre/card" section there are no models listed and the only hyperlink is one (presumably automagically added) to a mic-pre-only unit on Amazon. It's also buried down at the bottom, making it difficult for me to find (and I'm probably not the only one... I hope, heh). Anyway the other sections are comparatively very specific on equipment.
> ...


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## Wayne A. Pflughaupt (Apr 13, 2006)

> Anyway, regardless whether or not anything happens, thanks much for listening, Wayne.


No problem!  It’s actually a compelling idea, and it has been kicked around from time to time, but no one has followed through. 




> I guess the maintainer would need to become something of a "subject matter expert", and I don't think it would have to cover all of the options - or even say "this is the frequency response of this device", though I would want to include such for some of the more-typical devices (or maybe just a few words on it in pros/cons).


I’ve been here since the beginning, and except for a few, I don’t think I could definitively tell you what the “more typical devices” are! Early on the Soundblaster products were popular, with or without the inclusion of the Behringer XENYX 502 for those who wanted full range measurements. Then a few years ago we started hearing from new REW users about pro-audio “USB audio interfaces” that combined the sound card and mic pre-amp all in one package. The M-Audio Mobile Pre and TASCAM US122 / 144 seemed to get mentioned a lot, along with another brand whose name escapes me at the moment. Then someone discovered the Behringer UCA202 and that one “took off,” as it were, but IIR some people had major problems using it with Windows 7 or Vista (forget which).

Really, I think an easy way to accomplish this would be to start a sticky thread where people posted the brand and model of their sound card, their operating system, and noted the sound card’s pros and cons. That way no one really has to maintain it, and new posts would keep it current.

Regards,
Wayne


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## aackthpt (Jan 24, 2011)

Wayne A. Pflughaupt said:


> Really, I think an easy way to accomplish this would be to start a sticky thread where people posted the brand and model of their sound card, their operating system, and noted the sound card’s pros and cons. That way no one really has to maintain it, and new posts would keep it current.


That seems like it would be a reasonable start. I'd suggest not just sound cards but sound card (interface)/mic pre/phantom power source. One of the confusing parts about this was it being called a "sound card" ... sure I know the sound blaster is a sound card, but the M-Audio MobilePre USB sure didn't look like any sound card I'd ever seen before. But I love the out of it now!

I'll look out for that thread; I hope you start it or something similar.

Regards,
John


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## SAC (Dec 3, 2009)

Wayne A. Pflughaupt said:


> The price of the equipment has no bearing on any problems configuring or getting it to work with REW. We’ve had plenty of people come through here with high-priced gear that they couldn’t get to work.





Wayne A. Pflughaupt said:


> The beauty of REW is that it doesn’t require expensive equipment. No one has offered any proof that they got better results using high-priced sound cards and mics.



I won’t spend much time on this as is simply doesn’t justify it.

So now it is asserted that someone has necessarily associated ‘quality’ with price – as opposed to the necessary functional features such as dual channel, balanced inputs, phantom power and linear operation.

And actual measured performance of devices such as the Presonus Audiobox USB and the Duran Audio Axys den0monstrating the REAL differences in magnitude and phase linearity and a Significant different in unit noise floors certainly (sic) constitute “No one (offering) any proof that they got better results”. Of course, unlike the remainder of the quoted source, we on the other hand are quite able ’to get this equipment to work’! Not only that , but the Axys is indeed one of the standards in precision measurement and analysis – on ALL measurement platforms!

It is interesting to listen to some assert the necessity to buy a calibrated mic, yet they at the same time assert that the quality of the mic pre-amp has nothing to do with the accuracy and precision of the measurement. Unfortunately, they work together. Both require accuracy and precision necessary to encompass the desired use of the software. And if one seeks to measure and act on elements that are outside of the accuracy of the various IO devices, the results will not be accurate.

Thus as it has become rather commonplace lately on the forum to insist that one must EQ a sub in the lowest 5-20 Hz passband, then one must have measurement hardware capable of accurately measuring such data.

But, like it or not, the scope of one’s intended use does impact what hardware one employs. As there are various ranges in accuracy and precision. And simply obtaining a calibrated microphone is not sufficient to overcome issues of pre-amps whose low end is deliberately attenuated so as to protect against the passage of DC or units which lack sufficient phase linearity or which exhibit high noise levels that may impede measurements requiring such sensitivity.



SAC said:


> I know folks seem to think that since they are 'only looking at the LF extreme' that they do not need to invest in decent equipment, but the fact is, below 30 Hz, ANY results you get are suspect unless you invest in a good pre-amp and a good mic as the phase and accuracy of the frequency response below ~30 Hz WILL be inaccurate. You are simply reaching into a critical response region whereupon, you get what you pay for. There is no free lunch.
> 
> 
> 
> ...


The fact remains that there are several ranges of equipment capability. 

That which does fine for Most of what some may desire to do, but which does not have the accuracy necessary to do what many on the forum have asserted must be done (such as those repeatedly demanding the EQing subs to 5 Hz!!!)

And there is equipment capable of affording a variety of advantages in terms of either/or both low frequency and high frequency extension or noise floor levels – depending upon ones use.

Thus, such abilities are defined in terms of equipment features and specs. 

But if one wants to try to reframe this as a straw man debate over price, be my guest. But if one does find such gear with said performance levels for less, please post such information along with independently verified specs.

And has been previously stated many times, please be sure to evaluate the scope of your intended goals and do your due diligence to insure that the hardware that you use as your front end is capable to support the full scope of your desired use – and let THAT be the criterion that you use to determine which gear is most appropriate for your intended use.


And yes, it would be useful if a dedicated thread were available strictly for posting various compatible ensembles as well as actual measured specs of the various pieces of gear in order to help facilitate decisions regarding matching actual specs to intended use.


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## Sonnie (Apr 11, 2006)

John... we would be happy to discuss your ideas if you want to shoot me a PM.

As far as the links on the Downloads Page... I have added several links there on that posts that should help. It definitely sounds reasonable enough that they should be there. For the REW page that is linked from the icon up top... at the top of that page are several links, including downloads, forum and help links. At the top we have REW Downloads linked from the Quick Links menu... and on the home page we have a link on the left hand side under the "Site Navigation" menu that takes you to the downloads area. We haven't had many complaints about people being able to find it... it is pretty much all over the place. HOWEVER... we are always open to suggestions. They are harder to find deep within threads like this though... where the right folks may or may not see/read it. Our Forum Help | Suggestions forum was created specifically for this. Believe me... we would much rather have members offering suggestions rather than learning later somewhere deep in a thread they are complaining... no offense. :T



SAC said:


> I won’t spend much time on this as is simply doesn’t justify it.


Promises promises... yet impossible to accomplish. :whistling:



KalaniP said:


> Please understand that I appreciate your obvious knowledge and deep understanding of the subject matter, but the near-constant negativity and acerbic tone does grate from time to time. It makes it harder to appreciate the valuable knowledge that you are freely imparting.


Amen! And why is it that I am hearing this from fifty-eleven members? Some of that knowledge needs to be used on communication and people skills. 

SAC... we are all about wanting and desiring to provide good information. If you have an issue with something being recommended, come to the source rather than constantly beating members up over and over and over about it. Communicate directly with us if you wanna help, cause no one... and I mean no one wants to keep reading all your condescending whining about it over and over and over. 

Why don't we start a thread on updating the FAQ and recommended equipment if it is needed.

In the meantime... I think this thread has used up its usefullness on the OP's topic and needs to be closed.


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