# Understanding maximum volume (0db), with Audyssey



## JensToft91

Hello HTS!

It's been a while, since i posted a thread on these forums, feel free to move it, if i got the place wrong.

I recently upgraded my system with a used Denon 4311 - to get MultiXT32.
I absolutely love it - everything sounds like heaven, and the 140w pr. ch (170w in 2ch) does a good job driving my low-sensitivity speakers..

Back to my question - As i have understood, 0db on an AV receiver in "Max loudness", and everything above it will introduce digitial distortion, which sounds bad.

This 0db reference will be relative to any other setting in the receiver,
Ex. if -Front right- is set -2dB by audyssey the maximum loudness on my recevier will be at +2db.

I've been listening to music quite loud tonight, and noticed the midrange distorting at about -6db in my FR-speaker, which is odd - as i can play on 0dB in "Pure direct mode"..

I went to check my settings, and i quickly suspected the equalizer.

As it turns out, Audyssey made a 10dB boost in the 400-500hz region on my FR-speaker..

This brings us to my question:

Will my "maximum loudness" follow the following equation?

0dB - "Channel level" - "Max EQ boost" = "Max loudness"

In my situation:

0dB - (-2dB) - 10dB = -8
Which means that anything above -8dB, the receiver will introduce digital distortion at 10dB boosted areas of the equalizer?

Thanks in advance,

Jens


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## tonyvdb

Ok, let's see if I can help. 
Audyessey if run correctly during the auto setup will set all speaker levels so that when your playing at 0db on the receiver at your listening position will be 75db (reference level). When you listen in pure direct you bypass all eq settings of Audyessey and only the levels are maintained.


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## JensToft91

I do understand that part - but as you can see on the calculations, some frequencies will exceed the "maximum loudness" of the receiver, that is, if the equalizer "counts in"..

I think that might be a design flaw - which i can't see any solutions for, other that higher sensitivity speakers - which will result in channel levels at -10db, so there's a headroom for a 10dB boost in the equalizer section.


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## robbo266317

Not quite following you. Why do you suggest there will be digital distortion?


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## JensToft91

As far as i have understood 0dB on an A/V receiver is "Digital Full scale".. The maximum signal amplification, the maximum signal voltage..

Which means that, if the input is a full scale 200hz tone, and i set the amplifier at 0dB - i will get the maximum amplification of a 200hz tone.. Anything louder on the receiver, will result in clipping..

If the input signal is a -3dB (from full scale) 200hz tone, i will be able to set the amplifier at +3dB, before digital distortion will occur..

This is not something I've tried on my speakers 

Did i get it all wrong?


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## lcaillo

0dB on the amp implies zero attenuation. If you input a digital signal at 0dB and play it though your amp at zero attenuation, you sould be at the limit of the amp before clipping. When you calibrate your system to a 75dB reference level, this is not at full power from the amp. You can have your amp set for 0dB attenuation and never clip the amp with much lower level inputs.


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## JensToft91

But that doesn't answer my question.. As far as i have understood, what you say, is that if i didn't change any of the configurations on the receiver, 0dB will be max volume for my receiver..
But will the equalizer have an influence on this, as my first post implies?


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## lcaillo

I am not sure what 0dB means on your receiver, but you are correct if it means zero attentuation, or maximum gain in your amp. It is always a concern with equalization that you can easily exceed the dynamic range of the system. For most systems for most people, calibrating at a 75dB reference level leaves enough dynamic range in the system. If you are listening with only 6dB of attenuation, you could be driving the amp to clipping.


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## willis7469

0 is usually not the volume maximum. (Usually up to +10) Also this is not the threshold point for "digital distortion" as you mentioned. When you reach "0" on your receiver, the system should be playing back at the level for which a movie was mastered at. This is useless in music playback other than giving you your own personal reference point since music is mastered at almost random levels. +/- from 0 at MV 0 should be leveled in the avr during calibration for flatness, so a negative value trim number will actually be at "0". I think. 
Fwiw, "0" is loud, and I wonder if you cooked a driver. I might be on the wrong road. Just tryin...


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## rab-byte

Once you've gotten to 0dB you've stopped attenuating the input signal vs. reference. Once you've passed 0dB you've started amplification beyond reference.

When you EQ a system; you're calibrating how the system will behave when given a specific input. In the case of A/V we're calibrating signals from 20kHz to 20Hz trying to get each measured frequency to play at the same volume, a set volume or reference volume. In your case 75dB when the dial on your AVR/Pre-amp is set to 0dB.

If your EQ has dialed some frequencies up to 10dB then it is very possible that when playing at 0 you are pushing the amp, pre-amp, or speaker further than it's designed to go. A good way to think of this is that 0dB is 100%.

Typically when we hear amplification what we're actually thinking of is gain.


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## rab-byte

I think I'm doing a very bad job of explaining this sorry.


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## tonyvdb

JensToft91 said:


> But that doesn't answer my question.. As far as i have understood, what you say, is that if i didn't change any of the configurations on the receiver, 0dB will be max volume for my receiver..
> But will the equalizer have an influence on this, as my first post implies?


The Equalizer will have no influence on this if your still using pure direct as your mode of choice for listening as you state in your first post. The EQ is bypassed and so is all other processing only the trim levels are maintained.


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## AudiocRaver

JensToft91 said:


> This brings us to my question:
> 
> Will my "maximum loudness" follow the following equation?
> 
> 0dB - "Channel level" - "Max EQ boost" = "Max loudness"
> 
> In my situation:
> 
> 0dB - (-2dB) - 10dB = -8
> Which means that anything above -8dB, the receiver will introduce digital distortion at 10dB boosted areas of the equalizer?


Part of the problem here is confusion of terms. "0 dB" is your System Gain. Loudness equates to the rms level of a signal. Distortion starts at the Clipping Level. The difference between the rms level of a signal - usually during the louder passages - and the Clipping Level is Dynamic Range. Dynamic Range of an AVR will be more than 20 dB. Also, Dolby standard Reference Level is 85 dB, but that is kinda loud at home and a user can set this level to 80 dB or 75 dB or whatever according to personal taste. That Reference Level (for movies) is 20 dB below the Clipping Level, allowing for 20 dB of Dynamic Range when the Volume of a louder passage of a movie is played at your chosen Reference Level - let's say 75 dB for your example. The Volume for music varies all over he place. For loud rock or pop tracks, dynamic range might be only 6 dB, so playing it through your system with gain set at 0 dB System Gain will be LOUD, roughly 14 dB louder than the louder parts of a movie. With orchestral and jazz, dynamic range is often closer to 20 dB, so the loudest passages of a Beethoven symphony might sound the same Volume as your movies at 0 dB System Gain. Of course, you end up adjusting your System Gain all the time to compensate for these differences in real life.

It is true that a big EQ boost, whether in Audyssey MultEQ or elsewhere, in a listening mode where it is active, can "eat up" some of your available system Dynamic Range. A signal processor & amplifier will generally have some extra headroom built in to allow for that. A 6 dB boost at 1 kHz does not mean that 6 dB of Dynamic Range has been used up. It depends on the program material, the filter characteristics, and the frequency band. Generally, a low-frequency boost will more closely equate to the same amount of Dynamic Range reduction than a high-frequency boost. So a 6 dB boost at 1 kHz might only equate to a 3 dB (purely a guess) reduction in Dynamic Range, with a movie, perhaps a little more (4 dB ??) with compressed music.

This does not necessarily equate to a reduction in maximum Volume, but can if the clipping occurs in your power amplifier. It can occur anywhere in yuor system, but we usually thing of it occurring in the power amp.

The Channel Level is a trim which compensates for your speaker efficiency and room acoustics to allow you to set your AVR for 0 dB gain and have a Reference Level signal sound at the same Volume whether you have high-efficiency or low-efficiency speakers. This probably does not directly affect your perceived clipping level unless your AVR power is really low for your speakers &/or you listen at very loud levels.

Hope that does not muddy the waters.


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## JensToft91

Well, as far as i can read, there's different answers around..

But i do believe, that the big EQ boost at 200-400hz, reduces the dynamic headroom, in the 200-400hz region..

It was a jazz song, and it was only my front right, that distorted.. and it was this speaker, that was boosted in the 200-400hz region.. It was very audible, like the voice got all wobbly..

Well thanks for your answers!

I switched audyssey setting, to audyssey bypass L/r, because audyssey is simply too hard on my speakers and my room.. my great investment didn't help unfortunatly..

I calibrated my system 4-5 times a day, it was absurd.. Now i left it for good.


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## AudiocRaver

JensToft91 said:


> Well, as far as i can read, there's different answers around..
> 
> But i do believe, that the big EQ boost at 200-400hz, reduces the dynamic headroom, in the 200-400hz region..
> 
> It was a jazz song, and it was only my front right, that distorted.. and it was this speaker, that was boosted in the 200-400hz region.. It was very audible, like the voice got all wobbly..
> 
> Well thanks for your answers!
> 
> I switched audyssey setting, to audyssey bypass L/r, because audyssey is simply too hard on my speakers and my room.. my great investment didn't help unfortunatly..
> 
> I calibrated my system 4-5 times a day, it was absurd.. Now i left it for good.


Audyssey and other room correction technologies can really help but are not a cure-all.

Well recorded jazz tracks can have huge dynamic range. It is certainly possible - unusual, but not out of the question - that the Audyssey calibration boost cost you enough headroom to cause distortion on that track.

Recalibrating several times a day kinda takes the fun out of listening, doesn't it?

You might look into room treatment to eliminate the dip that Audyssey is compensating for.


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## JensToft91

AudiocRaver said:


> Audyssey and other room correction technologies can really help but are not a cure-all.
> 
> Well recorded jazz tracks can have huge dynamic range. It is certainly possible - unusual, but not out of the question - that the Audyssey calibration boost cost you enough headroom to cause distortion on that track.
> 
> Recalibrating several times a day kinda takes the fun out of listening, doesn't it?
> 
> You might look into room treatment to eliminate the dip that Audyssey is compensating for.


It does not just take the fun out of it.. It stops me from enjoying it at all.. 

I tried calibrating the system from a standing position, and got a totally different result.. Now I could actually hear the bass! But tricking audyssey this way doesn't really make sense.. But if I calibrate it in the right height, my speakers sounds like a cheap flat screen tv.. (yes, seriously) 

I suspect the wall to be the main issue, my couch I against the backwall, and if calibrations I made within 1m from this, it absolutely kills all life in my speakers.. 

Even now, with this "high" calibration trick, all bass notes are simply replaced with a dull and flat knocking sound.. 

I doubt that I will ever really fall I love with audyssey..


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## tonyvdb

Thats not Audyssey's problem as it has no way of knowing that your seating position is against a rear wall. Thats a huge issue as the bass and other frequencies reflected off the rear wall will mess the readings up. Its never a good idea to have any seating that close to a wall but of course in many cases there are no options but that is definitely an issue.
I would at the very least move the calibration mic forward into the room at least 2ft and try again.
I would also invest in some acoustic panels from GIK to place on that rear wall if you cant move the seats forward.


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## Talley

This is why acoustic treatments are still the preferred method of adjustments. Treat your room and get your room relatively corrected then the EQ process will be much easier to tame.


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## Meetdtaylor

Agreed, you are asking to much from your room correction software. I purchased room treatments from GIK and the results were totally worth the small investment. So much so that I treated my entire 1st floor. I understand the reluctance at first but once you really give it a try with enough panels to properly treat your room you will have an epiphany.


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## b bos37

Check this link on YouTube http://youtu.be/okyNlhJ3Hvo


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## JensToft91

I treated my room already, but maybe i should have a panel directly behind my head, and then try again..

http://imagizer.imageshack.us/a/img803/3834/65351581.jpg


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## chashint

Try putting the mic 2 ft in front of the primary listening seat, use a tripod (or rig up a stick with the mic on it), set mic height to seated ear level, mic points straight up, move mic about 6-12 inches L/R for the multiple mic positions.
Remove yourself from the room if possible during each measurement.

What speakers do you have?


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## chashint

I will give this a shot.


JensToft91 said:


> Hello HTS!
> It's been a while, since i posted a thread on these forums, feel free to move it, if i got the place wrong.
> I recently upgraded my system with a used Denon 4311 - to get MultiXT32.
> I absolutely love it - everything sounds like heaven, and the 140w pr. ch (170w in 2ch) does a good job driving my low-sensitivity speakers..
> 
> Back to my question - As i have understood, 0db on an AV receiver in "Max loudness", and everything above it will introduce digitial distortion, which sounds bad.
> after calibration 0dB on the volume control typically means the SPL of the system has been adjusted so it conforms to the THX reference for movies, since there is no standard for a source's output level 0dB is really only accurate using the AVR's test tone levels
> 
> This 0db reference will be relative to any other setting in the receiver,
> Ex. if -Front right- is set -2dB by audyssey the maximum loudness on my recevier will be at +2db.
> 0dB is after calibration is complete, when you look at the EQ +/- for each frequency you can see problem areas the calibration tried to address, the +EQ applied at each frequency band does consume overhead
> 
> I've been listening to music quite loud tonight, and noticed the midrange distorting at about -6db in my FR-speaker, which is odd - as i can play on 0dB in "Pure direct mode"..
> i don't know exactly what the Denon does in the different modes, but pure direct generally removes EQ
> 
> I went to check my settings, and i quickly suspected the equalizer.
> 
> As it turns out, Audyssey made a 10dB boost in the 400-500hz region on my FR-speaker..
> if the calibration is adding +10dB on one speaker only I would swap that speaker with its brother and see if the +10dB followed it, or if the issue is the speaker placement
> 
> This brings us to my question:
> 
> Will my "maximum loudness" follow the following equation?
> 0dB - "Channel level" - "Max EQ boost" = "Max loudness"
> in a home listening environment, no. 0dB is simply setting the SPL of the system to a known reference level.
> 
> In my situation:
> 
> 0dB - (-2dB) - 10dB = -8
> Which means that anything above -8dB, the receiver will introduce digital distortion at 10dB boosted areas of the equalizer?
> not necessarily, however +10dB of boost is huge and telling you there is a big problem with something in your system...speaker, speaker placement, room mode, maybe with the way the mic is being handled/positioned during calibration
> 
> Thanks in advance,
> FWIW once the system is calibrated you really should not have to touch it again unless you move the speakers or your listening position....getting new furniture would probably be a good reason to er calibrate too
> 
> Jens


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## JensToft91

That was a really thorough explanation.. I think I understand it now!

My speakers are hand-made by a professional, with great speaker units and filters..

When i get time on my hands, I will try to play around with the position, to eliminate that boost.

Actually i calibrated the system 3 weeks ago, and haven't touched it since!

I moved the microphone further away from the wall, and took about 5 measurement points with only vertical shift.. 

Like this:

,,,,,,,,,,,,,*,,,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,*,,,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,*,,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,*,,,,,,,,,,,,,,
,,,,,,,,,,,,,,,,,,*,,,,,,,,,,,,,,


Anybody can see, that this is a boom-arm, moving upward 

I know that is is not a recommended method, but it worked for me.. Quite well!'

Thanks for all the help guys 

:wave::wave:


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## chashint

I am glad you are now pleased with your system.
It can be very frustrating to invest your $$ into something and not get the results you were expecting.
You hung in there though and got it figured out.


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## tcarcio

I hope the OP doesn't mind me asking a question here but I didn't want to start a new thread just for this question which is within this topic. OK, I see that everyone says that after calibration 0db on the master volume will give you reference level of 75db but after I calibrate my Onkyo 809 and then put the master volume on 0db I get closer to 95db. After cal I checked speaker levels using the receivers pink noise in the menu and all speakers are set to 75db. So why when I set my receiver to 0db do I get 95db? I will say it is very loud but it is clear and has no distortion at that level.


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## tcarcio

^nobody?^


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## tonyvdb

That's correct, 95db is peaks (75db is the average)with all speakers and sub. You will even go to 105db in the sub domain.


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## tcarcio

tonyvdb said:


> That's correct, 95db is peaks (75db is the average)with all speakers and sub. You will even go to 105db in the sub domain.


OH OK, That makes sense. thanks Tony.....:T


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## tonyvdb

If you go into your receivers menu and play the level adjust test tones through the speakers at 0db on the dial one speaker at a time you should get 75db on your meter.


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## tcarcio

tonyvdb said:


> If you go into your receivers menu and play the level adjust test tones through the speakers at 0db on the dial one speaker at a time you should get 75db on your meter.


I did that and I have all speakers set to 75db so I think what you said before as far as peaks go is correct.


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## tonyvdb

Sounds good :T

I almost never run at 0db unless it's music for a short time as its just to loud it's clean but I usually play at about -15db or a little louder on the dial.


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## chashint

During the calibration the volume control setting has no influence and the 75dB SPL is simply a reference level the AVR uses to match speaker levels, set distances, and EQ the frequency response.
75dB SPL is loud enough to cover some ambient background noise but not so loud as to be obnoxious.

I am surprised you are getting 95dB SPL if you have the meter in the same place the calibration mic was in during the cal.
I would expect closer to 85dB give or take a little.


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## tonyvdb

chashint said:


> During the calibration the volume control setting has no influence and the 75dB SPL


We were talking about doing the manual test tones in the speaker level trim settings menu.



> I am surprised you are getting 95dB SPL if you have the meter in the same place the calibration mic was in during the cal.
> I would expect closer to 85dB give or take a little.


if you include the sub you will get higher average peaks than 85db. Your correct all main speakers should give an average level of around 85db but peaks will be higher.


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## tcarcio

chashint said:


> During the calibration the volume control setting has no influence and the 75dB SPL is simply a reference level the AVR uses to match speaker levels, set distances, and EQ the frequency response.
> 75dB SPL is loud enough to cover some ambient background noise but not so loud as to be obnoxious.
> 
> I am surprised you are getting 95dB SPL if you have the meter in the same place the calibration mic was in during the cal.
> I would expect closer to 85dB give or take a little.


I knew that about the volume during cal. I checked to make sure that my speakers were all set to 75db using the internal test tones in the AVR and then checked a couple of times what my meter read at "0" and your right it is running at 87db with peaks to 95-100db. Acyually it is exactly how Tony described it. When I checked the first time it was probably running at a peak reading and so that is what I reported but now I know it is definitely the later. Also I agree with you Tony that it is loud and I usually don't even play it that loud unless I am upstairs and want to listen there. My Cerwin Vegas handle it easily.


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