Re: [Discuss-gnuradio] ok, I'm lost

[Alexandru Csete]

On Wed, Mar 19, 2014 at 6:59 PM, djl <address@hidden> wrote:
> I'm trying to use gnuradio with wsjt. To do that, I need to make the gr
> audio source and sink look like a soundcard to the wsjt program. One might
> think this is simple; it is not or at least apparently not. I've been lost
> in the dismal swamp of the Linux sound "system" for about a week or so.
> What a mess. Lots of unclear info, looked at ALSA, Pulse (default on my
> 12.04 maachines) and Jack.  Nothing is clear.   It is clear that ALSA lies
> under all, that Jack won't play with Pulse, that pulse can be suspended
> before running the Jack server, and that there are very few people out there
> that REALLY understand the audio setup in Ubuntu.
> Anyone have a cooment? Is the easiest way really to put on another sound
> card and hook two of them back-to-back?
> Thanks, I'll keep swinging, even though the machine is throwing all sinkers
> :-)

Hi Don,

The audio system on Ubuntu is really simple: ALSA provides the low
level access to the hardware and on top of that you have pulseaudio
which is what applications are supposed to use. However, applications
can also use ALSA directly bypassing pulseaudio and this is what GNU
Radio does by default.

I do not know the wsjt application and what it uses for audio backend.
If it uses pulseaudio, you can try to use the "pulse" ALSA device in
gnuradio and route to/from wsjt using the pulseaudio volume control
application: pavucontrol.

If wsjt uses ALSA you can try to create an ALSA loopback device, which
sounds more like what you ask for. See for example these pages:
http://www.alsa-project.org/main/index.php/Matrix:Module-aloop
http://ubuntuforums.org/archive/index.php/t-914405.html

Note that your problem is not really a gnuradio specific issue and you
may get better answers on a linux or ubuntu forum.

Alex