[pulseaudio-discuss] Alsa output devices, able to use alsa plugin?

[Ng Oon-Ee]

Hi Tanu, and thanks...

On Wed, 2009-08-26 at 10:22 +0300, Tanu Kaskinen wrote:
> ke, 2009-08-26 kello 12:10 +0800, Ng Oon-Ee kirjoitti:
> > 
> > 1. Instead of "load-module module-alsa-sink device=hw:0,0", what should
> > I be using to load the appropriate device? Assuming I'm not using
> > module-hal-detect.
> 
> http://www.opensubscriber.com/message/fedora-devel-list@redhat.com/12018387.html
> 
Thank you.
> > 2. I'm interested in using an alsa plugin to modify pulse's output
> > before it hits my card. Specifically the alsaequal plugin. I have
> > specified it in my .asoundrc as below:-
> > 
> > ctl.equal {
> >   type equal;
> > }
> > pcm.plugequal {
> >   type equal;
> >   slave { pcm "plughw:0,0" }
> > }
> > pcm.equal {
> >   type plug;
> >   slave.pcm plugequal;
> > }
> > 
> > This works properly with aplay -D equal, of course. How do I modify my
> > device string in load-module module-alsa-sink to use the 'equal' output,
> > so that I can dynamically equalize the output before it hits the
> > speakers? Is this even possible?
> 
> load-module module-alsa-sink device=equal
> 
> You might also want to change the
> 
>     slave { pcm "plughw:0,0" }
> 
> line to
> 
>     slave { pcm "plug:front:0" }

> just to reduce ugliness (= unneeded assumptions). I'm not 100% sure that
> works, though. If it doesn't, just revert to the old version. Hmm...
> since pcm.equal is already of type plug, I think the line can be
> simplified to
> 
>     slave { pcm "front:0" }

First off, front:0 doesn't work with aplay -D equal.
> 
> I'm not totally sure about this either (fiddling with alsa config isn't
> one of my hobbies).
> 
> There are other approaches to equalization, but I don't feel like going
> in the details of those if this works for you. If you're interested, I
> just point you to this:
> https://tango.0pointer.de/pipermail/pulseaudio-discuss/2009-August/004730.html
> 

Anyway, I have the above (with slave changed to plug:front:0 as
suggested) in my .asoundrc. Once again, aplay -D equal works fine. When
I try load-module module-alsa-sink device=equal:-

[ngoonee at ngoonee-laptop ~]$ pactl load-module module-alsa-sink
device=equal
Failure: Module initalization failed

Besides the typo there (initialization, not initalization), somehow it
doesn't want to load my device. Any ideas? Am on alsa 1.0.20 and Pulse
0.9.15 (will be getting 0.9.16 soon, when the final release is done).