[pulseaudio-discuss] [PATCH 0/5] volume: Decrease PA_VOLUME_MAX to be < 2^31

[Arun Raghavan]

On Sun, 2010-10-10 at 13:03 +0100, Colin Guthrie wrote:
> 'Twas brillig, and Arun Raghavan at 10/10/10 11:30 did gyre and gimble:
> > On Sun, 2010-10-10 at 10:46 +0100, Colin Guthrie wrote:
> > [...]
> >> I'd also like to expose a new constant in the headers called
> >> PA_VOLUME_OVERDRIVE (or similarly named) that represents +11dB and
> >> should be our generally recommended "overdrive" (aka software
> >> amplification > 100%) amount for volume control UIs.
> >>
> >> Currently gnome-volume-control allows up to PA_VOLUME_NORM*1.5 which is
> >> ~= +11dB via current mappings, which is one reason why we previously
> >> decided on +11dB as our overdrive amount. That said, other volume
> >> control UIs (pavucontrol, kmix and, surprisingly,
> >> gnome-volume-control-applet) only allow volumes up to PA_VOLUME_NORM, so
> >> the idea would be to allow them to go right up to PA_VOLUME_OVERDRIVE,
> >> and hopefully implement an appropriate use of colours and markers etc.
> >> to make it clear to the user that they may not want to go >100% or risk
> >> clipping.
> >>
> >> http://pulseaudio.org/wiki/WritingVolumeControlUIs#Colouredvolumesliders
> > 
> > Sounds reasonable. Although, independent of the rest of these changes,
> > I'd also like to propose that the max. s/w gain (i.e. PA_VOLUME_MAX) be
> > decreased from its current value (~289 dB now, ~271 dB with my change)
> > to something more reasonable, like ~20 dB.
> > 
> > I came to this conclusion the hard way - while testing these patches, I
> > managed to turn up the volume high enough to temporarily damage my
> > hearing (it was a sudden burst, and I got to the off switch in time, so
> > no permanent damage done, I hope).
> 
> Urk! I'll try and type quietly...

:D

> > I understand that some overdrive is useful in general, but are there any
> > objections to capping the max. to something like ~20 dB?
> 
> I think that imposing a more sensible limit probably makes sense. I
> can't think of any practical reasons to push things to dB's > 20 ish so
> on the whole I'd be in favour of a more sensible upper limit.
> 
> Quite what that limit should be however is perhaps debatable so other
> opinions should maybe be canvassed to get the final 20dB upper limit.

Right, I'm pretty open to any sane limit - just want to establish what
that limit is. :)

Cheers,
Arun