[LAU] digital volume sounds better at 0 dB?

[Bearcat M. Şandor]

On Sat, 2010-06-19 at 12:18 +0200, fons at kokkinizita.net wrote:
> On Fri, Jun 18, 2010 at 05:57:46PM -0600, Bearcat M. Şandor wrote:
> 
> > > That means that you should turn down the power amp gain
> > > quite a bit.
> >
> > This is a low powered 10 watt max amp (class t chip)
> 
> That doesn't mean its sensitivity is low as well.
>  
> > The alsamixer volume controls make no difference at all to jkmeter, but adjusting the
> > volume on mplayer does. Is this the expected behavior? 
> 
> Yes.
> 
> > I was not sure how to activate K20 or K14 given 
> > jkmeter's interface.
> 
> See Robin's post.
> 
> > You mean individual application volume controls as opposed to the sound
> > card mixer is preferred?
> 
> If the application's gain control works on floating point
> samples, yes. 
> 
> The sound card's gain control works on the 24-bit signal.
> For a gain below 0 dB it reduces the maximum available
> output as well. For example if you set it to -18 dB (which
> is 1/8 linear gain), the DAC will never use the upper three
> bits - you now have a 21-bit system.
> 
> If the volume is set using a floating point gain control, and
> the soundcard gain remains at 0 dB you have the full range of
> the DAC regardless of volume.
> 
> Ciao,
> 

Fons,

Thank you! This is just the information i was looking for. *now* it
makes sense why i'm hearing such a difference with the sound card volume
up all the way and no deterioration when i adjust the software volume of
apps.  

I had always wondered about this. In my hi-fi mags (yeah, i know, i know
reading those things has screwed up my mind), many companies decry
digital volume controls, where other companies embrace them. This
difference between floating point and linear gain control is an
important one. Thanks.

Bearcat