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Discussion Starter · #1 ·
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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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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Discussion Starter · #3 ·
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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Discussion Starter · #5 ·
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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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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Discussion Starter · #7 ·
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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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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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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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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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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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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Discussion Starter · #14 ·
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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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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Discussion Starter · #16 ·
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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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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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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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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