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Does Foobar's Volume Control Degrade Sound?

post #1 of 20
1/20/05 at 2:14am
Thread Starter 
Is there any degradation of sound if I use the Foobar volume control?
I'm guessing it's just some 32-bit domain digital lowering, which shouldn't harm things, but since I've heard so many horror stories related to not using Kernel Streaming b/c of Kmixer...
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post #2 of 20
1/20/05 at 11:43am
I'm not sure how Foobar implements their volume control, but if it's done at 32 bits and applies dithering (I know this is an available option) I wouldn't worry about it. By the time you go from 32->16 bit resolution, you have reduced the amplitude by 96dB which is equivalent to the SNR of redbook. This is over-simplified, but demonstrates that there isn't a whole lot to worry about.
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post #3 of 20
1/20/05 at 11:53am
the volume control in foobar2k isn't the traditionanal volume control. it only attenuates the sound. in other words, it doesn't provide any amplification that could potentionally degrade the sound.
in my setup, i use the volume control and set it to -8db to reduce clipping. for actual volume control/amplification on rely on my headphone amp.
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post #4 of 20
1/20/05 at 2:45pm
Thread Starter 
Sounds like a good volume control then. I was just worried that it would reduce the dynamic range, as I've understood happens in other contexts (ie. if you connect an amp to the iPod's headphone out, lower the iPod's volume a lot, and raise the amp's a lot, then the sound i shorrible).
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post #5 of 20
1/20/05 at 5:09pm
Quote:
Originally Posted by Zoide
... as I've understood happens in other contexts (ie. if you connect an amp to the iPod's headphone out, lower the iPod's volume a lot, and raise the amp's a lot, then the sound i shorrible).
Is this from personal experience, or is what you're hearing anecdotal? The digital attenuator in the iPod works exactly like the attenuator in Foobar. Exactly alike.

(Yes, I know Foobar has an intermediate 32 bit stage, but once you requantize to 24 bits, the result is identical to a 24 bit integer hardware implementation, assuming no dither -- and dither at 24 bit is way beyond the threshold of audibility.)
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post #6 of 20
1/20/05 at 7:13pm
Quote:
Originally Posted by Wodgy
Is this from personal experience, or is what you're hearing anecdotal? The digital attenuator in the iPod works exactly like the attenuator in Foobar. Exactly alike.

(Yes, I know Foobar has an intermediate 32 bit stage, but once you requantize to 24 bits, the result is identical to a 24 bit integer hardware implementation, assuming no dither -- and dither at 24 bit is way beyond the threshold of audibility.)
If this is so why have some reported best SQ out of the iPod at a little less than max volume? (FYI, I have no experience, nor an iPod, just curious.)
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post #7 of 20
1/20/05 at 7:25pm
Quote:
Originally Posted by IstariAsuka
If this is so why have some reported best SQ out of the iPod at a little less than max volume? (FYI, I have no experience, nor an iPod, just curious.)
I imagine that full volume might drive certain amplifiers into clipping, or at least out of their linear range.
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post #8 of 20
1/20/05 at 7:31pm
Quote:
Originally Posted by IstariAsuka
If this is so why have some reported best SQ out of the iPod at a little less than max volume? (FYI, I have no experience, nor an iPod, just curious.)
Placebo effect? Clipping caused by using the equalizer?

Come to think of it, it is possible that the iPod designers are doing volume control in software, rather than using the DAC's internal 24-bit volume control. If the volume was implemented in this manner, it could be a 16-bit volume control, in which case it could be audible. Putting the iPod at a little less than max volume would cause additional quantization errors (i.e. added distortion). Some people might like this effect and think it sounds "better."
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post #9 of 20
1/20/05 at 7:46pm
The problem with determining how good Foobar's vol control is the impossibiliby of doing A-B comparisons. One can't A-B max volume vs. lower volume just because of the actual volume difference, which will cause perceived sound quality differences.

I can get close by using my EVS ultimate "nude" attentuators. I set the overall end volume to be the same, but create this volume by using Foobar vol control mostly vs. using EVS mostly. In this sort of test, Foobar vol control does not seem worse than the EVS, which is a fantastic volume control..
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post #10 of 20
1/20/05 at 8:41pm
so should i keep my foobar set to -8 and use my cmoy to control volume then? ive been keeping it at 0 and havent noticed any problems
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post #11 of 20
1/20/05 at 8:44pm
Thread Starter 
Hmm.... I'm currently using the Foobar volume control at -18.00 dB, and my amp's volume pot is only slightly above 9 o' clock. Maybe I should ask Xin to lower its gain.
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post #12 of 20
1/20/05 at 9:46pm
how do i know what to set my foobar DB to?
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post #13 of 20
1/20/05 at 10:27pm
Thread Starter 
Well, at least with columns UI it tells you in the bottom right of the window, in the status bar.
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post #14 of 20
1/20/05 at 10:33pm
Quote:
Originally Posted by Zoide
Well, at least with columns UI it tells you in the bottom right of the window, in the status bar.
It says so there in the default UI too.
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post #15 of 20
1/23/05 at 6:49pm
Quote:
Originally Posted by jefemeister
I'm not sure how Foobar implements their volume control, but if it's done at 32 bits and applies dithering (I know this is an available option) I wouldn't worry about it.
Actually, all processes are done at 64-bit float, and are dithered down in the output stage to whatever settings you have in Playback.
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