[pulseaudio-discuss] Sink volume linearity

[Lennart Poettering]

On Wed, 04.06.08 21:14, Matthew Patterson (matt at v8zman.com) wrote:

> Hello everyone,
> 
> I have been playing around with the volume control on my whole home 
> audio system trying to make it nonlinear so we are able to fine tune the 
> volumes we listen at most. Unfortunately it appears that the sink volume 
> controls do not allow enough range (I think this would be dynamic range 
> in audio terms). Basically, if I set the system up so 100% volume is as 
> loud as I want things to go, 1% is not quiet enough. I have tried 
> setting the sink volumes using pacmd where the range of volumes is 
> 1-65535. A value of 0 is muted, but 1 is quite loud.
> 
> Any thoughts/experiences on this?
> 
> I'm contemplating setting both the stream and sink volumes so I can have 
> more granularity of control.

PA tries to use the sound card volume control if possible. However
most sound cards only a allow a limited range of volume control. With
many sound cards the lower volume boundary does not result in total
silence. 

I will eventually add support to PA that we can extend the volume
range to the same dB range on all machines, regardless of what the
hardware provides. We can do this if ALSA exports dB information to us.

Of course, each sound card as a maximum gain for the output. We cannot
go higher than this, regardless whatever we try, unless we resort to
dirty stuff like doing the amplification in software, which is most
likely not what you want on 16 bit audio.

May be some of the auxiliary controls of your sound card mixer also
influence the final volume of your audio? You might want to play
around with your ALSA mixer with alsamixer -c0.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4