# Sticky  What is "reference level"?



## event horizon

Having just typed this into "search" on here & having found over 20 pages which really weren't what i was looking for i thought i'd ask - what is "reference level"? That'd be with regards to films & home cinema..

This year i'm hoping to build what should be my final speaker system :T

My idea is simply to design & build a 2 channel system that will produce as little distortion as possible & generate 116db from 20Hz to whatever the poor tweeter will withstand. Yes high frequencies do tend to drop off somewhat so i live in hope. The system will be 4 way active per channel.

As well as this i'll be rebuilding Paradigm's top of the range C5 V2 centre speaker & adding what i'd regard as a driver that can do real bass to it 15" with decent excursion. Poor thing is sitting here in it's box waiting for me to pull it to bits 

Rear speakers aren't a problem as they'll be much nearer me than the front & centre speakers. Not sure i need to fuss over a sub as a few staff members have put my mind to rest that the LFE is directed to the front left & right speakers when it's set to "off".

*So, can someone help me & let me know what is meant by "reference level" when dealing with films etc.*

I guess as long as it's less than 116db i have nothing to fuss over as that output would be anechoic & the room will add some gain at low frequencies, at a guess i'm probably looking at 120db+ at 20Hz & 115db at 15Hz with what i'm going to build.

Thanks for your time 

Mark.


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## tonyvdb

Reference level is the volume at 75db (decibels) in your room using full band pink noise. When you set up your system and you run pink noise through your speakers one at a time setting each level using an SPL meter to 75db you will (after all channels are done) and your volume control is set to 0db you will achieve "reference" when playing back movies or music. Movies will tend to reach peaks of 115db with your system set up properly.

This is not always easy to do as most home theatre systems can not reproduce this without distortion and is usually louder than most people go. Unless you have fairly expensive gear and larger speakers you likely wont achieve this without distortion.


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## event horizon

tonyvdb said:


> This is not always easy to do as most home theatre systems can not reproduce this without distortion and is usually louder than most people go. Unless you have fairly expensive gear and larger speakers you likely wont achieve this without distortion.


Cheers Tony, thanks for taking the time out to reply :T

I'm mainly a 2 channel man but HT has given me a bug (as well as a huge projector screen & 1080P tv), definately since one music label i listen to a lot does a lot of 5.1 DTS music releases. Yes, i'll agree that the volume level that i should likely attain will be ridiculous, which is precisely the point! It should mean that any sane volume level will be reproduced with minimal distortion.

All via sealed boxes btw, i'm not in to reflex muddiness. Ta again for the reply. 75 db, i'll say nothing more


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## SteveCallas

85db is actually reference level, and in order to have a reference capable system, you need 20db dynamic headroom from each channel. 75db is what some discs or receivers have you calibrate to using their test tones simply because 10db less is easier to withstand during calibration. The LFE channel is 10db louder, so reference is 95db with the need to be able to handle 115db.

So to sum it up, if you are designing new speakers, the capability you need is for them to reach 105db across their intended range *at your seat *and the subwoofer 115db. If you cross the speakers over at 80hz, then the subwoofer system actually needs to be able to do ~118db.


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## event horizon

SteveCallas said:


> So to sum it up, if you are designing new speakers, the capability you need is for them to reach 105db across their intended range *at your seat *and the subwoofer 115db. If you cross the speakers over at 80hz, then the subwoofer system actually needs to be able to do ~118db.


Cheers Steve, looks like i should well be able to manage that :whistling: No problem whatsoever with the full range stuff, though i'll be pushing it with the bass end possibly :blink:

Any idea on what the "sub" would need to output if crossed over at 100Hz? The only reason i ask is simply because i'll be doing things a little differently. You see i want the main left & right speakers to be full range for stereo (music man you see) & they'll be using 2 x 15" in a sealed box for bass (each side). These drivers have a one way Xmax of 17.5mm (35mm pk-pk). Now WINisd pro tells me i should get approximately 116Db at 1M with these drivers (excursion limited) @ 20Hz, but that's anechoic.

I'll not be running a sub channel as i've been reliably informed that if i set this to "none" it'll force all the bass to the front left & right speakers when watching films. However there will be another 15" driver in a sealed box added to the centre channel & this one has an Xmax of 14mm one way which should happily produce another 102Db @ 20Hz or add another 2Db to the output. I'm sure that like the left & right front channels there is bass applied to the centre channel, even if a sub is enabled.

The surround speakers also happen to happily go down to 27.5Hz to, though at a lesser level. They'll be approximately 1M from me behind me to the left & right strangely enough 


You know, listening to a single bass driver of the same size doing it's thing i'm having incredible difficulty in imagining what 4 of them would do at 20Hz. According to equal loudness curves the output will virtually triple in loudness (actual volume level) with doubling the drivers at 20Hz & then do the same again with 4 drivers :rofl: Think i'm going to need to cure the door from rattling & other stuff besides when this gets operational.

Cheers for your input & have a good 2010!

Mark.


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## SteveCallas

If you don't have a dedicated subwoofer, then the LFE channel will be directed into only the L&R mains. Every other channel would need to be able to handle 105db across the entire intended frequency range. The L&R mains would need to be able to handle 115.4db below 120hz and 105db above 120hz.

Keep in mind, you probably won't listen at reference, it is quite loud. Also, remember that these upper limits for reference level capabilities need to be achieved at the seat, not at 1m from the drivers.


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## event horizon

Cheers Steve, yes the left & right mains will be good for 116Db (1M) from anywhere from 600Hz down to 100Hz where they cross over to the 15" bass drivers (that's per channel). The bass drivers will be excursion limited to 109Db per channel but at 20Hz, they can do a lot more at a higher frequency as you can probably imagine.

Looks like i have it sussed & yes you are right - the volume level will be nuts. Again the idea being that you aren't pushing the system at any volume until it becomes uncomfortable to the listener.

It should result in a low distortion system at any reasonably acceptable level :T It'll just have some reserves


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## SteveCallas

If the speakers are near the corners or a wall, you will get boundary gain - that will help. Also, room gain will set in at some point on the low end. 

Based on how you described your setup, I take it you are going to run every channel as "large" and set the sub to "none"? Every speakers will get it's full 3hz-20khz signal and the mains will also get the 3hz-120hz LFE channel.


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## tonyvdb

SteveCallas said:


> If the speakers are near the corners or a wall, you will get boundary gain - that will help.


This is true for the sub but never a good idea for the mains or surrounds. Having speakers in or too near a corner will cause cancellation of some of the frequencies due to reflection off the side walls called first reflection cancellation.


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## Jon Liu

Like Tony said, corner loading speakers even subwoofers isn't necessarily the best thing to do. A lot of times boundary gain helps boost levels, but it doesn't necessarily boost all frequencies equally causing some cancellation as Tony mentioned, too. For subwoofers, I tend to find corner-loading them make them sound boomy.

As far as reference level at home, personally I find it somewhat hard to listen at that level. I usually listen at anywhere between -10dB to -20dB under reference at home. I don't know, it's not that it's necessarily that loud, but it just feels different. Maybe it's just a combination of things, like worrying about neighbors, worrying about who else is home, etc.


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## event horizon

SteveCallas said:


> Based on how you described your setup, I take it you are going to run every channel as "large" and set the sub to "none"? Every speakers will get it's full 3hz-20khz signal and the mains will also get the 3hz-120hz LFE channel.


Yes, spot on! You see i still want the same performance give or take when i listen to 2 channel music.


Jon Liu said:


> As far as reference level at home, personally I find it somewhat hard to listen at that level. I usually listen at anywhere between -10dB to -20dB under reference at home. I don't know, it's not that it's necessarily that loud, but it just feels different. Maybe it's just a combination of things, like worrying about neighbors, worrying about who else is home, etc.


Agreed, however there are mad occasions when i like to go a little mad lets say  99% of the time i probably listen to somewhere about 90Db at the listening position, though as the evening wares on i might turn it up a bit, followed by a bit more...

The idea is simply to make a system that will be more than i ever need. Thus i'll be the one that backs down when things get loud, rather than the system producing vast quantities of distortion.

I'll not be deliberately loading the bass drivers with either the rear or side walls, i know what nasties that can produce. I'm not into one note or boomy bass :rolleyesno:


Thanks for the comments everyone! When i get building you can be sure of seeing a thread on the subject, i'll guess it'll be in "full range" speakers - simply because they will be :T


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## Jon Liu

True, I will admit that I do push my system beyond the level of my own comfort zone on occasion!


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## chadnliz

What size room and how much power do you have for all that?


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## gperkins_1973

Reference level is something you don't play when the neighbours are in.


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## Cincyborn

What is "reference level"?

Reference Level is the volume where your neighbor, that doesn't share your taste, Calls the Police!


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## event horizon

Jon Liu said:


> True, I will admit that I do push my system beyond the level of my own comfort zone on occasion!


lol, i'll tell you a little story.. End of an evening & i retired to a different room where i was listening to some music on a pair of Celestion Ditton 66 monitors. The music was great & sounded fantastic so it got a little loud.. So loud in fact that a rather heavy 15" sub that was sat on top of one of the Celestion cabinets decided to walk off of the top & drop iteslf on a recently disconnected digital TV box. At the time i didn't see the damage that the 15Kg driver caused :yikes: Yes i'd had a few drinks, but man the music sounded good.. Was i upset at the crushed TV box. Not really 


chadnliz said:


> What size room and how much power do you have for all that?


5 x 4M with a Mackie M3000 to drive the subs, should do the trick me thinks 


gperkins_1973 said:


> Reference level is something you don't play when the neighbours are in.





Cincyborn said:


> What is "reference level"?
> 
> Reference Level is the volume where your neighbor, that doesn't share your taste, Calls the Police!


Actually i can get away with any volume level that doesn't involve Saturn V take offs. Nice solid brick built house which is totally detached. The window has been "filled in" as i have a PJ in here for movies so no rattling glass etc & a nicely low lit room for these purposes. Never had a single mention asking me to turn it down a bit.

& that's not because i haven't heard people knocking at the door :T


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## bambino

Cincyborn said:


> What is "reference level"?
> 
> Reference Level is the volume where your neighbor, that doesn't share your taste, Calls the Police!


Been there, next time it's a ticket not a ''could you please turn that down''.


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## Spuddy

bambino said:


> Been there, next time it's a ticket not a ''could you please turn that down''.


The trick is to passive-aggressively mention to all the neighbors that they should feel no remorse in telling you to turn it down, and even on top of that let them know in passing that you plan on watching such and such at a certain time, so give a call if it's a problem. They'll smile and say it's never been a problem even if it annoys them, and you have nothing to worry about.

It's actually pretty amazing what a smile and a forewarning can do for leniency towards sound levels allowed during a movie  Of course, once I close on my new house my theater will be surrounded by concrete and 10 acres for a buffer zone, so my little "good neighbor SPL levels" problem won't last much longer anyways


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## Lucky7!

Spuddy said:


> The trick is to passive-aggressively mention to all the neighbors that they should feel no remorse in telling you to turn it down, and even on top of that let them know in passing that you plan on watching such and such at a certain time, so give a call if it's a problem. They'll smile and say it's never been a problem even if it annoys them, and you have nothing to worry about.
> 
> It's actually pretty amazing what a smile and a forewarning can do for leniency towards sound levels allowed during a movie


I live in an apartment and have done this with my neighbours and don't see how it is passive aggressive. I also asked that if it became an issue, to let me know 'when' so we could work out what I was watching, how loud etc and if it were at an odd time so I could maximise my fun at minimum inconvenience to them. So far zero complaints, but I tend to crank it at reasonable times and watch dialogue driven flicks at less friendly times like late at night.

Movies I also find are less of an issue than modern music with a regular beat. Doof, doof is more annoying to many than a couple of minutes of not readily identifiable loud noise from a movie which is not consistent or predictable.

I'm still going to add more soundproofing as I work on the room acoustics as I would like even less potential for neighbour disturbance and for me to play louder at times.

Solid walls and acreage would be nice but lotto-win dream for many of us unfortunately.


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## bambino

Spuddy said:


> The trick is to passive-aggressively mention to all the neighbors that they should feel no remorse in telling you to turn it down, and even on top of that let them know in passing that you plan on watching such and such at a certain time, so give a call if it's a problem. They'll smile and say it's never been a problem even if it annoys them, and you have nothing to worry about.
> 
> It's actually pretty amazing what a smile and a forewarning can do for leniency towards sound levels allowed during a movie  Of course, once I close on my new house my theater will be surrounded by concrete and 10 acres for a buffer zone, so my little "good neighbor SPL levels" problem won't last much longer anyways


Being that my neighbors are hard to track down i had conciderd putting a sign out in the front yard telling them that if it's too loud just let me know instead of calling the police. But that would just invite thieves, allthough with too ''monster dogs'' in the house i really don't think any uninvited guests would enter.

My solution to the problem has been to keep the volume at a recpectable level, i've got 13 month old twins now anyways so turning the volume up isn't really an option anymore. Problem solved.:clap:


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## ironglen

Wow houses must vary considerably: with an 18 and two 12's in the HT I can easily hear a 50 cal machine gun outside or at the front door when I watched the Big Red One; I figured someone would think it was the real thing if they walked by! lol!!!
Our windows don't rattle annoyingly, nor have I had any 'walking' objects. It's not too noticeable past the front curb, maybe 20ft from the front door; I don't want to listen at higher volumes than that anyway. The entire house thunders though!


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## Spuddy

A9X said:


> I live in an apartment and have done this with my neighbours and don't see how it is passive aggressive. I also asked that if it became an issue, to let me know 'when' so we could work out what I was watching, how loud etc and if it were at an odd time so I could maximise my fun at minimum inconvenience to them. So far zero complaints, but I tend to crank it at reasonable times and watch dialogue driven flicks at less friendly times like late at night.
> 
> Movies I also find are less of an issue than modern music with a regular beat. Doof, doof is more annoying to many than a couple of minutes of not readily identifiable loud noise from a movie which is not consistent or predictable.
> 
> I'm still going to add more soundproofing as I work on the room acoustics as I would like even less potential for neighbour disturbance and for me to play louder at times.
> 
> Solid walls and acreage would be nice but lotto-win dream for many of us unfortunately.


Yeah, maybe "passive aggressive" was the wrong language to indite; What I meant was that the more subtle hints regarding your inclination to be a good neighbor that you can express to the surrounding community, the more leniency you will be given towards playing movies at higher volume levels now and then as a direct result. If only everyone knew how far a smile would take them, I should think there would be a lot more smiling in the world today (even if for purely selfish reasons :huh: )

As for a house on 10 acres.. It sure seemed like a pipe dream to me 2 months ago as well, but simply asking a family friend/realtor if I had a chance at home ownership turned out to be one of the best decisions I've ever made, because I was pleasantly surprised to learn that even owning a home, period, was possible for me now. If you have a steady job, look into buying- you might just be as surprised as I was!


bambino said:


> Being that my neighbors are hard to track down i had conciderd putting a sign out in the front yard telling them that if it's too loud just let me know instead of calling the police. But that would just invite thieves, allthough with too ''monster dogs'' in the house i really don't think any uninvited guests would enter.
> 
> My solution to the problem has been to keep the volume at a recpectable level, i've got 13 month old twins now anyways so turning the volume up isn't really an option anymore. Problem solved.:clap:


Lol, turn it down and problem solved! That's a good point on inadvertantly letting the world know you have expensive gear inside as well.. I'm not used to having anything worth stealing, so this is taking some getting used to haha


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## bambino

Yeah like i said also, i don't think any uninvited guest will attempt to come in do to my ''security dogs''. Also i've relized that when the kids are at grandma and grandpas as long as it's the right time of day it's ok to rock out a bit but advertising your awesome setup to the world isn't really the best idea anyhow.


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## GranteedEV

Spuddy said:


> As for a house on 10 acres.. It sure seemed like a pipe dream to me 2 months ago as well, but simply asking a family friend/realtor if I had a chance at home ownership turned out to be one of the best decisions I've ever made, because I was pleasantly surprised to learn that even owning a home, period, was possible for me now. If you have a steady job, look into buying- you might just be as surprised as I was!


Totally agree. 
plus, IMHO:

paying rent means your money goes away
paying mortgage means your money is here to stay


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## Emuc64

Spuddy said:


> As for a house on 10 acres.. It sure seemed like a pipe dream to me 2 months ago as well, but simply asking a family friend/realtor if I had a chance at home ownership turned out to be one of the best decisions I've ever made, because I was pleasantly surprised to learn that even owning a home, period, was possible for me now. If you have a steady job, look into buying- you might just be as surprised as I was!



I just recently bought my first house. With the low interest rates, I'm paying $225 more per month for my single family detached house. For me, it was totally worth it to not have to share walls. Ahhhh... I can finally play my games & movies as loud as I want. And I can turn my subwoofer up past 2. It goes to 10.


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## bambino

Reference level is when you have An XPA-1 hooked up to each of your towers and you start to smell magic smoke.:whistling: Oh, wait, that would be beyond reference level.:yikes:


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## gsmollin

SteveCallas said:


> 85db is actually reference level, and in order to have a reference capable system, you need 20db dynamic headroom from each channel. 75db is what some discs or receivers have you calibrate to using their test tones simply because 10db less is easier to withstand during calibration. The LFE channel is 10db louder, so reference is 95db with the need to be able to handle 115db.
> 
> So to sum it up, if you are designing new speakers, the capability you need is for them to reach 105db across their intended range *at your seat *and the subwoofer 115db. If you cross the speakers over at 80hz, then the subwoofer system actually needs to be able to do ~118db.


What do you mean by "20 dB dynamic headroom"? How does one calculate and/or measure the available dynamic headroom?


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## GranteedEV

gsmollin said:


> What do you mean by "20 dB dynamic headroom"? How does one calculate and/or measure the available dynamic headroom?


You use the onlline SPL calculator (google it) and see if your amplifier can drive your mains to 105 db at the listening position, and you can find out if your sub can do 115 db AT 20HZin various ways.

However that doesn't factor in thermal compression. Even if your amp can drive your speakers to 105db, your speakers may lose their compusre at those peaks. 

Most people's systems can't do reference levels properly. Regular tweeters just don't have the thermal power handling to do so. You usually need some sort of waveguide or horn loading for the tweeter, or a non-conventional multi-tweeter speaker design like the RBH T2 system. My tweeters for example actually have limiting in which they can't sustain anything above 103 db before the protection kicks in. They can do a dynamic transient higher, but not sustained. I've never heard my speakers compress, but then I don't own a pair of JTR Triple 8s to reference them against either.

Professional audio speakers are much more capable of the dynamic range which we associate with movie reference levels.


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## gsmollin

The SPL calculator does not address "dynamic headroom". It actually disclaims dynamic headroom in the text. Quote: "This calculator does not account for room acoustics, amplifier dynamic headroom or off axis listening positions." If you are really expecting 20 dB of crest factor in your program material, you will need a 10 kW amplifier for a typical home theater. Of course no HT speaker can withstand 10 kW, even on a program peak. I think the old rule of 10-13 dB of headroom is more realistic of program material. Remember we are already considering the loudest passage that the sound system will encounter.


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## Lucky7!

gsmollin said:


> The SPL calculator does not address "dynamic headroom". It actually disclaims dynamic headroom in the text. Quote: "This calculator does not account for room acoustics, amplifier dynamic headroom or off axis listening positions."


Dynamic amplifier power is nothing more than marketing rubbish.



gsmollin said:


> If you are really expecting 20 dB of crest factor in your program material, you will need a 10 kW amplifier for a typical home theater. Of course no HT speaker can withstand 10 kW, even on a program peak. I think the old rule of 10-13 dB of headroom is more realistic of program material. Remember we are already considering the loudest passage that the sound system will encounter.


10kW, really? For an 88dB speaker on it's own at 4m with 800W you get THX ref level at the LP of 105dB. As I presume it is 2 or 4 pi space and not a room where the reverberant sound will also add to the apparent level, and the recommendation from Toole (IIRC, not in front of me ATM) is 3dB not 6dB loss per doubling of distance, then we're back to 400W. High, but not unrealistic.

Now get some sensible speakers with decent efficiency and volume displacement and reference at the LP is easy.

Dialogue is supposed to be mastered at the 75-85dB level and with peak loudness at 105dB, a 20dB+ crest factor is not unrealistic. Just make sure you have enough speaker and amp to do it.

Calculator used is from here. [first google hit]


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## gsmollin

A9X said:


> Dynamic amplifier power is nothing more than marketing rubbish.
> 
> 10kW, really? For an 88dB speaker on it's own at 4m with 800W you get THX ref level at the LP of 105dB. As I presume it is 2 or 4 pi space and not a room where the reverberant sound will also add to the apparent level, and the recommendation from Toole (IIRC, not in front of me ATM) is 3dB not 6dB loss per doubling of distance, then we're back to 400W. High, but not unrealistic.
> 
> Now get some sensible speakers with decent efficiency and volume displacement and reference at the LP is easy.
> 
> Dialogue is supposed to be mastered at the 75-85dB level and with peak loudness at 105dB, a 20dB+ crest factor is not unrealistic. Just make sure you have enough speaker and amp to do it.
> 
> Calculator used is from here. [first google hit]


No, actually not 10 kW. According to your example, you need 20 kW. The problem comes down to what we mean by "Watts". 

The first mistake in all the calculators is that there is no such thing as "Watts RMS" in these calculations. The simplest, arithmetic form of the equation is Volts, RMS X Amps, RMS = Watts, average. So now we know that we are taking an average power. 

The second problem is the speaker sensitivity measurement. As I understand it, the sensitivity measurement is taken driving the loudspeaker with a sine wave. Beginning with that, and working through the calculator with your example, we get 105 dB SPL with 800 W average. But that would be a scaled version of the speaker sensitivity measurement at 105 dB instead of 88 dB. That is not home theater. My question in all this is how to relate this to home theater, which I presume is employing movie soundtracks, and not sine waves.

I believe this all comes down to the "dynamic headroom" which is allowing for the difference between average and peak power in the program content. In the speaker sensitivity test, using sine waves, the peak power in the speaker is 2X the average power. This happens because the sine wave applied to the speaker has a peak voltage that is the square root of 2 higher than the RMS value of the waveform. Since power is proportional to the square of the applied voltage, at the peak of the waveform the instantaneous power is twice the average power. This, BTW, is the genesis of "peak power ratings", which are not rubbish. As we say, figures don't lie, but liars figure. Peak power is often presented to be the same thing as average, which it isn't, and that part is the marketing rubbish. But I digress.

As we all know, 2X the power is 3 dB. So your amplifier needs 3 dB of "dynamic headroom", just to reproduce a sine wave. However, this headroom is already included in the amplifier's power spec, so we don't add it in twice. So what dynamic headroom should we be allowing for when we wish to reproduce movie soundtracks? 

Some years ago, this problem was faced by broadcasters who had the same problem trying to broadcast program material without over modulating. A noise signal was developed, based on work done characterizing radio program material. This noise signal became known as _USASI noise_ and a standard containing the definition of this noise source is given here: http://www.nrscstandards.org/SG/NRSC-1-A.pdf

Page 17 of this standard shows this noise spectrum. Note that it rolls off at 6 dB/octave on both sides of the peak at about 200 Hz. A study of the peak-average ratio, or crest factor of USASI noise reveals that it is 10 dB. This means that to reproduce 88 dB of USASI noise requires 10 dB of dynamic headroom, or 10X amplifier power to reproduce the random peaks of the signal. In other words, you can run the 88 dB speaker sensitivity test with a 1 W amplifier, but if you used USASI noise you would need a 10 W amplifier to produce 88 dB on your SPL meter.

Going through the SPL calculator with your example, and listening at 105 dB, you need 8 kW of amplifier power, or if you use the -3 dB/double distance rule for a reverberant room instead of the -6 dB rule for free-field conditions, it requires 2 kW. (You quadrupled the distance to 4 m so you saved 6 dB of amp power.)

Now, in your example, you were quoting a 20 dB crest factor. I only subscribe to 10 dB, which I have justified above. However, the broadcast industry's program material model may be too compressed for the movie industry, and 20 dB may be closer to the truth. If that were true, then add another 10X to amplifier, and get 20 kW required power.


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## Sir Terrence

Since nobody has really address this question, I will. Reference level is not 75db or 85db. It is actually 0 digital reference, or the loudest digital signal before system overload. So reference levels for the cinema would be 105db for each main channel, and 115db for the LFE based on 0 reference. This would be continuous output, and nobody can really stand this kind of output continuously.


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## GranteedEV

Sir Terrence said:


> Since nobody has really address this question, I will. Reference level is not 75db or 85db. It is actually 0 digital reference, or the loudest digital signal before system overload. So reference levels for the cinema would be 105db for each main channel, and 115db for the LFE based on 0 reference. This would be continuous output, and nobody can really stand this kind of output continuously.


Does this mean it's impossible for a signal to ever peak above these?


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## Sir Terrence

GranteedEV said:


> Does this mean it's impossible for a signal to ever peak above these?


Yes the signal can peak above 0db, however it is pure distortion at that point. It is truly not something you want to hear.


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## THOMASWMAZ

your question to me is very broad.... you speak of what is reference, do you mean reference level speakers? reference level processors? reference level amplifiers? maybe your looking for mid-fi equipment which is still very expensive but not in the 100k level? mid-fi is generally 18-28k+ for a theater system approximately.. first if you say that this is the last system you want to buy you need to define a budget, before you go any further.

just my .02

thomaswmaz


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## GranteedEV

THOMASWMAZ said:


> your question to me is very broad.... you speak of what is reference, do you mean reference level speakers? reference level processors? reference level amplifiers? maybe your looking for mid-fi equipment which is still very expensive but not in the 100k level? mid-fi is generally 18-28k+ for a theater system approximately.. first if you say that this is the last system you want to buy you need to define a budget, before you go any further.
> 
> just my .02


I think you're totally lost my friend. This thread is discussing the strict definition of "reference level" sound pressure levels IE the sort defiined by Dolby or THX or whomever.


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## q2bon2b

Emuc64 said:


> I just recently bought my first house. With the low interest rates, I'm paying $225 more per month for my single family detached house.


Congrats on your first home. The hard work pays off. And now the sweet joy of ownership - playing music to your "reference level.":T

I can't even rent a room for $225 around here. So envious!


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## beyond 1000

I have little problem in reaching reference levels as I have Klipsch RF-82s for mains and my 5 speakers are driven by a new 80lb Outlaw 7500 power amp and my subwoofer is the 160lb SVS PB13 Ultra (with Sledge amp). Watching War of the Worlds proved to be profound. I metered the system at 116.5 db with both the power amp and sub driving that sound pressure level effortlessly. For your interest, the scene where the pods blow up the bridge behind Ray's (Cruise) house is the loudest in the movie. 

SPSs at 90db is more then good for me for 2 hours while 82db-85db is a comfortable continously LOUD listening level. 

Thanks for everybody's analysis. You guys definitely know a lot more than me.


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## waricle

Had a good summer storm here today, lots of thunder and lightning so I put TRON on and cranked it up to eleven and threw away the knob.
That movie is AWESOME at reference levels. I judge my reference level the same way as we did it when I worked at the local twin cinema, the dialogue should be clearly audible and let a couple of Kw of amps and LOTS of subs take care of the rest.
A soundtrack with good dynamic range like TRON is a great indicator.
Trouble is you can only play it during the day, the sound would carry blocks away during the night!!!
I use two active 15" vented subs via FBD plus twin 12" sealed just to augment the centre channel.
-Plus a bunch of amps from the receiver pre-outs.
Add a 6meter screen and Bob's your uncle!!


----------



## beyond 1000

waricle said:


> Had a good summer storm here today, lots of thunder and lightning so I put TRON on and cranked it up to eleven and threw away the knob.
> That movie is AWESOME at reference levels. I judge my reference level the same way as we did it when I worked at the local twin cinema, the dialogue should be clearly audible and let a couple of Kw of amps and LOTS of subs take care of the rest.
> A soundtrack with good dynamic range like TRON is a great indicator.
> Trouble is you can only play it during the day, the sound would carry blocks away during the night!!!
> I use two active 15" vented subs via FBD plus twin 12" sealed just to augment the centre channel.
> -Plus a bunch of amps from the receiver pre-outs.
> Add a 6meter screen and Bob's your uncle!!



This is arguably the best explanation of FUN in one's system that I ever read. That is movie watching. 

My two favourite lines are...

Cranking it up to eleven and throwing away the knob.
Add a 6 meter screen and Bob's your uncle.


That's the way it's done and bollocks to the neighbours. :hsd:


----------



## waricle

Love the disintegrating house smilie!
You wouldn't be dead for quids, would you?


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## eyleron

gsmollin said:


> No, actually not 10 kW. According to your example, you need 20 kW. The problem comes down to what we mean by "Watts".
> 
> The first mistake in all the calculators is that there is no such thing as "Watts RMS" in these calculations.


I think you're conflating amplifier dynamic headroom with spl formulae?
It doesn't matter how you get there: it will take a number of watts using a number of distance to yield a number of SPL.

Since 105dB is referring to peaks, and not continuous, then this would correspond to transient program signals (typically < 200 ms) and an amplifier's peak undistorted transient output watts, which for highly regulated amps might be the same as RMS, and for other loosely regulated amps might be another 3dB (2x) of watts.

If your calculations of tens of kW in a home were true, then we would also never reach even 95dB in the home without thousands of watts per channel. I can reach 95dB from one speaker @ 10ft with a continuous sinewave, let alone a peak.



gsmollin said:


> Now, in your example, you were quoting a 20 dB crest factor. I only subscribe to 10 dB, which I have justified above. However, the broadcast industry's program material model may be too compressed for the movie industry, and 20 dB may be closer to the truth. If that were true, then add another 10X to amplifier, and get 20 kW required power.


Unfortunately, for music, one must guess, average, or survey for different types of music and their crest factors (average to peak ratio). Highly compressed pop music can be 3dB. Very dynamic music like certain classical will be over 20dB.

Fortunately, for films, you don't have to "subscribe" to any crest factor, as there are standards. 20dB is coming from 85dB average level with peaks of 105dB per channel (excepting LFE and summed bass, which can be 115 to 118dB).


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## eyleron

Sir Terrence said:


> Since nobody has really address this question, I will. Reference level is not 75db or 85db. It is actually 0 digital reference, or the loudest digital signal before system overload. So reference levels for the cinema would be 105db for each main channel, and 115db for the LFE based on 0 reference. This would be continuous output, and nobody can really stand this kind of output continuously.


While you're right about reference level referring more accurately to 0dBFS, you're mixing up average dialogue level with peak level. Peak is 105dB. Average is 85dB.

You're right that people can't stand 105dB, and fortunately, they never need to. They can withstand 105dB quite readily.

Speaking of tolerance, I didn't see a mention of how it's difficult to relate one's experience with 105dB peaks, due to the varying methods that people employ to test, and the varying qualities of home theater systems. It's fairly difficult to achieve 105dB peaks undistorted in the main channels, and it is VERY difficult to achieve the accompanying LFE peaks of 115dB-118dB!

For main channels, we need real high power handling speakers, and the amps to feed them hundreds of watts per channel, or speakers that are sensitive enough to achieve that output on less power. This usually means sensitivities in the low-to-mid-90s, at least.

To test, one cannot simply play a 105dB sine wave, as that's a continuous signal, which is much more challenging on the amp and speakers. While speaker and amp manufacturers tried to quote spec's based on 80ms peaks in the past, I see 200ms quoted more often, and I read that in an AES paper recently.

There are short burst tones that one can use to simulate a program peak. I think a lot of SPL meters also may not be able to log a max spl of such short duration, but I don't know. Does anyone know what the limits are of the Radio Shack and Galaxy meters, and a common rig of EMC8000 & REW in recording brief peaks? Ideally, one could output burst tones that could be monitored for THD.

You can also find out the recorded program peak of a film, like "-2dBFS @ 200Hz @ 1:19:04" and monitor to see if you achieve that, and how clean that sounded. It's more difficult to discern distortion in the brief peaks, but at some point one's speaker will make bad noises instead of good sound, or it just simply won't achieve that desired level.

Clean, undistorted, unclipped peaks are revelatory. It doesn't sound so "loud," but rather more "real" and effortless. Soundtracks often sound "loud" due to the distortion from the amp or speakers. Or from the reflections from an untreated room.

What are y'all's thoughts on what the threshold should be for achieving reference level LFE? [email protected]? [email protected]?

For those interested, I have a list of reference level speakers. It contains some classic high sensitivity speakers, some uber-sensitive ones, and a lot of pro speakers. The latter range from "colored" stage speakers, to studio nearfield, midfield monitors, and control room speakers (for big rooms), to "audiophile" designs to $20,000+ designs. There are also some near-reference-level speakers to educate using edge cases.
The list is sorted by output level, and I think it's interesting to see one model stick out like a sore thumb (due to the color grading), and then I see that while it had lower sensitivity, it has high power handling (which means it's a reference level speaker as judged by its own specs) and just needs to be run with a high power amp.


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## eyleron

GranteedEV said:


> However that doesn't factor in thermal compression. Even if your amp can drive your speakers to 105db, your speakers may lose their compusre at those peaks.
> 
> Most people's systems can't do reference levels properly. Regular tweeters just don't have the thermal power handling to do so.


While I agree that a common design to achieve these higher levels is using a horn, or a horn/compression drivers, I don't think thermal power handling comes into play for the *peak levels* being discussed. From what I read, and what speaker designers say, thermal compression is for longer signals. The brief transient peaks are limited more by other mechanical compression and magnetic compression effects.

Power compression (thermal) appears at even 1/10th the speaker's rated power handling, as a fraction of a dB reduction in output at certain frequencies. At 1/2 power, I have seen 1.5dB, and at full rated power, 3-4dB variances. This now only reduces output, but it changes the frequency response of the speaker. 

A few manufacturers like JBL Pro publish these numbers. I think we all wish that more did!


----------



## GranteedEV

eyleron said:


> While I agree that a common design to achieve these higher levels is using a horn, or a horn/compression drivers, I don't think thermal power handling comes into play for the *peak levels* being discussed. From what I read, and what speaker designers say, thermal compression is for longer signals. The brief transient peaks are limited more by other mechanical compression and magnetic compression effects.


How long is brief? How short is brief?

This is something I was told by a driver designer:



Paul Appollonio said:


> Music definitely has peaks, and averages, but they move about so quickly without a quantifiable definition we are waving at flies with our hands. Let us assume a peak with a duration of 0.1 second. That is a reasonable amount of time to call a peak a peak. We could integrate it longer or less, but I would argue integrating less than 33 milliseconds is likely useless, as that seems to be the approximate integration time of our ear brain mechanism. So, regardless of the duration of the peak, the VC will eventually get hot. What you find in a speaker is two time constants, one for the VC, and another for the motor surrounding it. You could count the box as a third, but this is a tertiary effect. The VC time constant of a small woofer like this is probably on the order of 3 seconds. Now, if you look at music which is typically played or recorded today, you will find the actual dynamic range QUITE limited. This means the difference between peaks and Rms is now very small. That makes a difference. Todays recordings have a dynamic range which is very limited relative to for example, a recording of a symphony orchestra.
> ...
> As for heating and compression, this is not difficult to measure. ANYONE who can come up with $15 and find their way to Radio shack can buy a meter that will measure DCR. Measure the speaker at the terminal with the amp disconnected, and the woofers cold. Play your speakers for an hour, as loud as you want to, then quickly disconnect the amp, and measure the speaker again. As long as there is no loud noise after you turn off the speaker, or as long as you don't have a fan or wind blowing at the cone, you should be able to get a somewhat stable DCR reading. That will tell you just how far off center the heat has pushed the device. I can measure it other ways, but I've thousands of dollars worth of gear to do that. You can calculate the heat in the VC based on the difference between the starting and stopping DCR (assuming any series choke presents a negligible amount of DCR in addition to your VC). All speakers heat up. My point was if I want 105 db EITHER peak or Rms in the room (RMS would be loud too) then having 8-10 db more sensitivity to begin with is a big advantage.


----------



## eyleron

*Peak Duration, How to Test*

Great point...how long is a peak? It'd be nice to know how long THX thinks it is, in regards to their amp and speaker testing.

I've read 200ms a few times, or the typical length of a quarter note. Here's an AES paper I read about it, where 200ms was considered a typical peak duration in many genres of music: The Dynamics of Recorded Music. The paper quotes another study saying that music peaks range from 8dB (rock extra compressed by the FM radio station) to 20dB (probably classical, and would apply to films) above average levels.

The thesis was that for typical program material < 200ms, on a budget one could use an amp that had enough dynamic headroom for planned peak levels, with the RMS being a fraction of peak output.
The worst cast peak duration in some pieces still suggests that to cover those worst cases of over 200ms, one should consider the amp's RMS rating and not the dynamic rating, as some peaks were up to two seconds long.

Here's another AES paper (that I only read the abstract on) that says 80-200ms: A Musically Appropriate Dynamic Headroom Test for Power Amplifiers.

So, if one accepts the above and wants to apply to peaks for speakers, the questions are, "How much heating does the voice coil undergo in 200ms," and "How much heating in 2 seconds?" I definitely can't test the 200ms per se, unless I download some shaped tone burst files and have some means to script their playing, but as you quoted, it looks easy to test resistance after playing some program material like music or a film soundtrack.

I suppose a 2 second sinewave could simulate the worse case.


----------



## eyleron

I have since learned that it's not heating of the voice coil we have to worry about for short term peaks, but rather Xmax, mechnanical excursion, and magnetic flux effects. Is the magnetic field linear as the driver is forced into greatest excursion? 

Drivers that are loafing along using a small fraction of their peak-handling capability are less likely to exhibit distortion.
Those that are at or beyond their limits will distort those transients even more.

The distortion may be an altered frequency response, as some of the drivers handle the signal differently, and it can be as benign as simply "lopping off the tops of the waves," which means you've lost that visceral immediacy from losing dynamics. Instead of a short 1/5 second rise of 25dB, you may only get 20dB, for instance.


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## eyleron

eyleron said:


> While you're right about reference level referring more accurately to 0dBFS, you're mixing up average dialogue level with peak level. Peak is 105dB. Average is 85dB.
> 
> You're right that people can't stand 105dB, and fortunately, they never need to. They can withstand 105dB quite readily.


Hmm I see well after the fact I meant, "They can withstand 105dB *for a fraction of a second* quite readily."


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## georgeallen

really great information for that concept i am totally unaware about that.


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## Nitrofreakman

tonyvdb said:


> Reference level is the volume at 75db (decibels) in your room using full band pink noise. When you set up your system and you run pink noise through your speakers one at a time setting each level using an SPL meter to 75db you will (after all channels are done) and your volume control is set to 0db you will achieve "reference" when playing back movies or music. Movies will tend to reach peaks of 115db with your system set up properly.
> 
> This is not always easy to do as most home theatre systems can not reproduce this without distortion and is usually louder than most people go. Unless you have fairly expensive gear and larger speakers you likely wont achieve this without distortion.


Just a question, when you say set the volume at 0dB, do you mean the AVR volume ? My Yamaha AVR's volume display reads in negative values at low volume( it starts at -80, then goes up to +15 ) so the closer you get to 0, the louder it gets, and if you go louder, the numbers become positive values up to +15. At 0 volume, it is excessively loud, and past half volume, -10 is very loud. I find this negative volume display very confusing on Yamaha AVRs..can anybody shed some light on why it's a negative value on the loud end ? How do you read it ? ( I also find the dBFS negative reading confusing on dB meters, but I'll start a thread somewhere else for that ) Thank-you in advance.


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## sound pioneer

*What is meant by "reference level"?*

I'm really not sure what this term means......I think it must pertain to the volume level. But what is it exactly.


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## BD55

*Re: What is meant by "reference level"?*

Here's the thread.


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## sound pioneer

*Re: What is meant by "reference level"?*

Oh, thanks......I need to search more.


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## SubSolar

*Re: What is meant by "reference level"?*

Means far louder than most people listen to.


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## Greenster

What level do you usually watch movies at? 85hz seems very loud to me.


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## mcascio

*Re: What is meant by "reference level"?*

Man - I'm usually watching movies at just under 50hz. 

There's been a few times where I've pushed the Denon 4520CI to reference and it's extremely loud for my tastes. I guess if you continue to listen at those levels, you'll start to go deaf and that then becomes the normal listening level.


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## tbaudoin

*Re: What is meant by "reference level"?*

I can't wait to get hit on the head after this comment. 

The way I take it, is the following:

It's the point at which all speakers come together to produce the same volume of output relative to 0.

Example: if my test tone from the receiver (or if you use a disc as this source) is at 80 (can verify the number by looking at the volume on the display in my case, then I calibrate the individual speaker levels with an SPL meter at 75 say, and then 0 is really 75db, not 80. Then, I find, it's not too loud to be at reference (0).

All you AV pros, please be gentle on this. It was trying to oversimplify and generalize... Please add in any technical points so we can all learn how to get better experiences and enjoyment from our equipment without going overly crazy.


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## AudioDawg

As an aside...

There is no reference level in 2 channel audio.

The music industry has no real guidelines and this explains the wide volume levels your music is produced at.

In the film industry, the mastering is done at 85db. In the music industry, sometimes they just turn it up to 11.

So, for 2 channel music you will need to keep that volume control handy. :bigsmile:

If you play your music through your HT system then all that balancing the system with pink noise will do is assure you that both speakers are the same volume level. Still very useful.


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## 16hz lover

My reference level is far from 90% of the people on here. it is the actual level of being on the stage with the musicians, or in video, the level it would take to convince a blind man the sound was not coming from speakers but was really happening near him. 99% of all systems fail to deliver this. It is called a "reproduction system" for a reason.


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## Greenster

16hz lover said:


> My reference level is far from 90% of the people on here. it is the actual level of being on the stage with the musicians, or in video, the level it would take to convince a blind man the sound was not coming from speakers but was really happening near him. 99% of all systems fail to deliver this. It is called a "reproduction system" for a reason.


That is the best explaniation I have heard. It makes total sence to me when you put it that way. :T


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## 16hz lover

Greenster said:


> That is the best explaniation I have heard. It makes total sence to me when you put it that way. :T


Yep, everyone has a different level due to their experience in life. Many times I've read a post where they comment about their sub shakes the whole apartment complex, and they're talking about their 8" model with a 200 watt plate amp. Now take that person and have him listen to a system with 16 or so 18" drivers, each with 3" of excursion powered by a 6K watt amp, and their frame of reference changes forever. 

Like the old quote says, "Contentment is destroyed by comparison"


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## AudioDawg

I prefer...

There is no replacement for displacement.


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## NBPk402

We just got back from a local Movie theater where I ran an app from my phone that shows the DB levels... It showed peaks of only 90db while watching Robocop. Pretty much the same as what I watch movies at home at.


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## A/V

I love this discussion. I don't have a THX certified AV receiver so I'm going to run some dB tests to see what reference level actually is on my system. I don't think I would ever listen at that volume though in our small living room.


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## goatfarm

My Onkyo 702 is THX certified. Doesn't make it reference. But for me reference level is pretty much when I can't take it anymore. Everything is almost (important) maxed out.


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## Philip Nel

I think reference level is any Level the Director or sound engineer or whom ever is responsible for the sound on a movie, decides it should be and what he finds appropriate for the viewer to experience the movie the way he intended., I do believe that in the movie industry there is certain guidelines as to what it should be, and in order for it to be a THX certified copy that reference level is stipulated at 85 db.

On every THX certified amplifier 0db on the diplay is considered the reference point at which the required 85db volume is achieved but please bear in mind that this is also related to room size and the power required to achieve the required volume in that space hence the reason why some amps are THX I/S plus, THX select (smaller rooms) and THX ultra (for larger rooms) Check THX website for specifics. http://www.thx.com/consumer/home-en...ter/thx-certification-performance-categories/

This does not mean that 0db on every amplifier can be considered to be "reference volume" as stipulated by THX, on a non THX amp this can be anything. 

So if you want to find out what reference level is on your amplifier is my suggestion would be to use the test tones on a THX certified disc and turn up the volume on you amplifier until you get a 85db reading on your SPL meter.

my 2c


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## Gregr

well..., we have stumbled upon a place I feel history is stranger than fiction. The question is "what is reference level", in fact a far cry from how do we measure "reference level". I love 16hz's explanations and I see 16hz is a preferred frequency so I will start at the beginning and hope this includes all instruments..., an important question when considering real sound reproduction and reference sound reproduction.

Well I'll admit I've read every post until page two when I realized we were saying the same thing in deferent words I believe believing we were saying something more..., well...

Let's start at the beginning..., "What is "Reference Level" sound". Come on???? think about it. Wait..., only for a minute. Reference is the sound of an instrument played at its natural reference sound level. So..., but then, a bass drum is louder than a flute when played in chorus and not in refrain or at least, it must be etc etc etc..., or, is it???? Well this is the question. So this naturally leads me to the question what is the loudest natural instrument in the orchestral pit..., played at natural or its normal levels and levels, not within refrains nor at solo intervals. I can only imagine these measure at 75 to 85db for brass instruments, of course depending whether the instrument is one of a reference quality instruments e.g. Stradivarius or the like instrument. In any case, what is this "reference" idea. Well the idea of a reference level is an admirable idea but how do we measure this esoteric idea :foottap:

Now..., moving on, I remember as easy as it is to identify the loudest instrument in the orchestral pit, as a brass instrument,
Well..., Ii would say "the loudest instrument" it must be based in reality at some point and we must adjust other instruments and adjust recording levels to this level..., at some point. 

Now, I ask you..., what is this level of optimal play back and in effect optimal recording???????????? Imagine recording at anything less than this optimal reference level.... 

I'll pause here


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## goatfarm

I only wish that motion picture reference level was the same as orchestral reference level. I generally listen to movies at below reference level because I believe that room size has an effect on percieved volume. 85dB w/ 105dB peaks is just not comfortable for me and my stablemates, even though distortion is at very low levels. BUT. I listen to symphonic orchestral music at levels much higher than I would hear it live in a concert hall outside the first few rows. Why? Because I can, and it gives me a more visceral response. Bruckner and Mahler come to mind. Even so there's no way I or anyone else can realistically reproduce the sound of a pipe organ in a cathedral.


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## mdrums

16hz lover said:


> My reference level is far from 90% of the people on here. it is the actual level of being on the stage with the musicians, or in video, the level it would take to convince a blind man the sound was not coming from speakers but was really happening near him. 99% of all systems fail to deliver this. It is called a "reproduction system" for a reason.


Yep I agree!

I'm a drummer by trade...lots of live touring gigs in the past...I know loud and it can be very uncomfortable to most. 

I can say that my system will run you out of the room with the volume at 0db. At -80db it shakes the screen and it at rock concert level at the sound board. My room is 24x20 10' ceiling, acoustically treated. I've never ever understood this so called reference level of 0db and I find movies and concert blu ray mixed hotter than others.


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## eyleron

It's much less fuzzy and subjective than you are making it out to be. Like you are discussing what the term "fast" means to you, vs the term "speed of sound at sea level."

Movie Reference Level, 0dbFS, is: at the listening position being assessed, the volume level is such that each channel will produce a maximum of 105dB, except LFE, which shall be 115dB.

Now, whether one likes that level or not is another issue.
And even that is complicated. To return to the analogy of speed...
In a 1950s car, going 70mph on a winding road might seem insanely fast and uncomfortable. Your spouse is screaming, "Too fast!" but what she or he really mean is, "Too fast in this car on this road!"

In a 2014 Porsche or similar, it doesn't seem so fast. Tires aren't screeching losing traction, the body isn't shaking and rolling and creaking, the engine isn't straining.

So, is Reference Level too loud for you and yours? Is your equipment and room capable of attempting this without producing objectionable noises and distortion?

For most people, no, it's not capable. And winding road torture test of home theater audio, deep bass in LFE channel, renders no one subwoofer capable of passing.


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## dreamerpuppy

Wow ! you guys give me so much to think about. I am now officially terrified to be here. I know so little and need to know so much. I will never even come close to your gear. I hope you all can put up with my lack of knowledge. I love HT though so we have that in common if nothing else. I thought I knew what reference level was. I guess not.


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## mvision7m

I agree with those who have said...

Once calibrated, a surround system's speakers (5.1/7.1/9.1 or 11.1) should be level matched (relative to each other) to 85db (strictly speaking) or 75db (more tolerable/less likely to break something) at the 0 volume position on your pre-pro, processor except for the subwoofer (the .1) which should be 10db higher if your particular sub can achieve that without falling apart at the seams (literally). 

Room acoustics, size and layout all play a role in how your system sounds and whether or not it will achieve reference level at the listening position without distortion.


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## Lumen

eyleron said:


> It's much less fuzzy and subjective than you are making it out to be. Like you are discussing what the term "fast" means to you, vs the term "speed of sound at sea level."


Good analogy, eyeleron, terms like "fast" are qualitative rather than quantitative.



eyleron said:


> Movie Reference Level, 0dbFS, is: at the listening position being assessed, the volume level is such that each channel will produce a maximum of 105dB, except LFE, which shall be 115dB.


Correct, technically speaking (please see next comment).



eyleron said:


> Now, whether one likes that level or not is another issue.


And that's where house curves come into play. You're probably already using one, if even if you don't know what it is. Ever bump-up the subwoofer level after auto-EQ or manual calibration? Well, you've just created a house curve!


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## Lumen

dreamerpuppy said:


> Wow ! you guys give me so much to think about. I am now officially terrified to be here. I know so little and need to know so much. I will never even come close to your gear. I hope you all can put up with my lack of knowledge. I love HT though so we have that in common if nothing else. I thought I knew what reference level was. I guess not.


Welcome, dreamerpuppy! We were all in your shoes once, and we all have to start somewhere. Please read my comments above. Also, you can check out the STICKY threads at the top of any forum for general info. Glad to have you here, and don't be afraid to ask questions! :wave:


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## Desertpilot

Maybe I am oversimplifying this question but I am looking for the easy route to "reference" level. My system includes a Marantz AV7702 Pre plus 200 watt per channel Outlaw Amp plus SVS Ultra 5.2 speakers. Forget the subwoofers for the moment. If I run Audyssey XT32 from my Marantz, it sets the trims and distances for all 5 speakers. The results look appropriate. I then crossover at 80hz.

After having done this exercise, if I turn up the Marantz volume to 0, am I at "reference" level?

Thanks!
Marcus


----------



## eyleron

Desertpilot said:


> Maybe I am oversimplifying this question but I am looking for the easy route to "reference" level. My system includes a Marantz AV7702 Pre plus 200 watt per channel Outlaw Amp plus SVS Ultra 5.2 speakers. Forget the subwoofers for the moment. If I run Audyssey XT32 from my Marantz, it sets the trims and distances for all 5 speakers. The results look appropriate. I then crossover at 80hz.
> 
> After having done this exercise, if I turn up the Marantz volume to 0, am I at "reference" level?
> 
> Thanks!
> Marcus


Yes, insomuch as you are "giving the gas" to achieve such. 

Many speakers can't output at that level from 12 feet away. And must that do produce a great deal of distortion, so there's not noise than good sound. 

Sent from my SM-G930V using Tapatalk


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## Gregr

Desertpilot said:


> ... then crossover at 80hz.
> 
> After having done this exercise, if I turn up the Marantz volume to 0, am I at "reference" level?
> 
> Thanks!
> Marcus


Good Question,
Essentially "Reference Level" is critically important in the recording studio. For many reasons an established recording Sound Pressure Level (SPL) for all recorded sound is predetermined and used universally by recording engineers etc etc. 

Recorded music, movie soundtracks etc recorded at Ref Levels are then calibrated and ready for intended play back levels predetermined by recording artists and engineers etc. :nerd:

In order to play back recorded soundtracks at intended ref levels your electronic equipment must have the ability to generate its own "pink noise" and you will need an SPL Meter. :spend:

Using the pink noise generator you must then calibrate each speaker volume to register 75db on the SPL meter (subwoofer adjusted to 85db) this is a "C Weighted" ref level sound playback. 

However, hearing and listening for each individual is not linear or interpreting sound volumes is different for each individual and even the same person can hear a recording played back at the same volume as loud when listening late at night or quiet when listening at midday. :huh: 

The easy "ref level" check for me is a sound system that is calibrated to playback uniform sound at appropriate SPL along with speaker timing delay etc etc e.g. all else being proportional to sound volumes of the original musical instruments and/or original sounds recorded. E.G. a ref level is hearing a sound played back sounding like the original sound at volumes listened to at that moment of origination. 

Enjoy - :yikes:


----------



## FargateOne

Gregr said:


> Good Question,
> Essentially "Reference Level" is critically important in the recording studio. For many reasons an established recording Sound Pressure Level (SPL) for all recorded sound is predetermined and used universally by recording engineers etc etc.
> (...)
> The easy "ref level" check for me is a sound system that is calibrated to playback uniform sound at appropriate SPL along with speaker timing delay etc etc e.g. all else being proportional to sound volumes of the original musical instruments and/or original sounds recorded. E.G. a ref level is hearing a sound played back sounding like the original sound at volumes listened to at that moment of origination.
> Enjoy - :yikes:


Knowing that timing delay etc etc is done properly, if I listen my ht 5.1 always around 70 db 68-db, is it better to calibrate the SPL of each channels at 70db instead 75? or it does'nt make any difference at the MLP?


----------



## Lumen

FargateOne said:


> Knowing that timing delay etc etc is done properly, if I listen my ht 5.1 always around 70 db 68-db, is it better to calibrate the SPL of each channels at 70db instead 75? or it does'nt make any difference at the MLP?


The lower you calibrate, the closer you are to your system's noise floor. It will make a difference (in headroom) for acoustic measurements, but shouldn't make much difference at the MLP. I think calibrating to 70dB instead of 75dB will just change how much you'll need to turn your AVR's master volume to reach the same SPL as before.


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## willis7469

Lou, I think your right. 
http://www.acousticfrontiers.com/2013314thx-reference-level/
I like this explanation in"reference" to the title.


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## eyleron

FargateOne said:


> Knowing that timing delay etc etc is done properly, if I listen my ht 5.1 always around 70 db 68-db, is it better to calibrate the SPL of each channels at 70db instead 75? or it does'nt make any difference at the MLP?


Doesn't make a difference, unless your receiver does some dynamic eq whereby the farther you are below reference level, the more bass and treble are boosted (a la equal loudness curves). Some Denons do this. 

I also like to have receiver report master volume in terms of reference level, like instead of "70" it'd be "-15 dB". The latter can be related to others like "My speaker rattles at -5 dB mv (12 feet)..." then I know you were 5 dB below reference level from 12 feet away, which is 80 dB average levels with 100 dB peaks. One could even infer, knowing the speaker in question, how many watts it was drawing and yield help like, "Dude, that speaker has a dip to 3 ohms at 100Hz mid bass. You were probably sending (or at least trying to send) 200w to it, when it can only handle 85w." 

Sent from my SM-G930V using Tapatalk


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## Arnkatla

Dynamic equalizer makes all the difference.


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