[LAU] digital volume sounds better at 0 dB?

fons at kokkinizita.net fons at kokkinizita.net
Fri Jun 18 20:41:07 UTC 2010

On Fri, Jun 18, 2010 at 11:17:16AM -0600, Bearcat M. Şandor wrote:
> My system is set up as follows: computer with Asus Essence ST sound card
> out to Trends Audio ta-10.1 amp to anthony gallo acoustics speakers.  
> In the alsamixer console program i note that the meters turn red as you
> get towards the top but i think that's just a pre-set color band and
> isn't really telling me anything about clipping or over-driving the
> card. More important is the 'dB gain' indicator. Correct?  

The meters are probably completely useless.

The chip used in your soundcard has a digital gain control
with a range of 0...-120 dB in steps of 0.5 dB. Does that
correspond to what alsamixer is showing ? If not you'd
better leave the gain at 0 dB.

If that soundcard really has the dynamic range that the
sales blurb claims it has, then its output level will be
a lot higher than what is expected by the average non-pro
amplifier, including 'audiophile' ones.

That means that you should turn down the power amp gain
quite a bit.

The correct alignment procedure would be:

1. Play a piece of music representative of what you 
normally listen to. Check the digital level with e.g.
jkmeter, For classic use the K20 mode and ensure you
have a level around 0 dB. For pop use the K14 mode
and again ensure you have around 0 dB.

2. Set the gain of the soundcard to 0 dB,

3. Adjust the gain of the power amp to the maximum volume
you'd ever expect for this tyoe of music. 

4. If you want to avoid an analog gaing control use a software
gain control (preferred), or the ALSA gain setting as your
volume control.

> I seem to hear that when the dB gain is at 0 (volume at 100%) and i've
> adjusted my integrated amp to the same (as far as i can tell) volume
> that i would have listed to with the alsamixer control at 70 (dB gain
> -18.00)  that the sound is much fuller with better bass.  My mate seems
> to hear that as well.

If the gain setting of the card has any impact on the magnitude
or phase response then simply the card is out of spec.
If the gain control of the power amp has any impact on the same,
again it's probably out of spec.

As long as you don't overload anything, there should be no difference.
Things like 'fuller bass' are impossible to comment on. If in doubt,
*measure* it.



O tu, che porte, correndo si ?
E guerra e morte !

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