[pulseaudio-discuss] Scarlett interface as default device

[Len Ovens]

On Wed, March 20, 2013 12:07 pm, Rodolfo Thomazelli wrote:
> Hi,
>
> in my research I want to use an signal analyser program called "mataa", an
> extension of Octave. The extension works with the default audio device.
>
> I have an usb audio interface called scarlett 8i6. With the help of the
> members of the "alsa-user" list (especially Daniel Mack, in cc:), we
> resolved some problems of Ubuntu on the device configurations. Now, the
> usb
> device is listed as the following log shows:
>
> /proc/asound/cards
>  0 [PCH            ]: HDA-Intel - HDA Intel PCH
>                       HDA Intel PCH at 0xf7e00000 irq 45
>  1 [USB            ]: USB-Audio - Scarlett 8i6 USB
>                       Focusrite Scarlett 8i6 USB at usb-0000:00:1d.0-1.2,
> high speed
>
> The problem is that the usb device is not showed in Ubuntu's audio pane,
> so
> I can't make it the default device. Typing F6 in alsamixer, scarlett is
> listed as well, but I can't controll it or make it the default device. I
> think that here is an importante information: the command "aplay
> -Dplughw:USB some-test-wave.wav" returns me sound from the device output.

I can not tell you why your alsa device does not show up in pulseaudio, it
may need a special profile. However, if your USB device is plugged into
your computer all the time (from boot) you can do one of two things if
your application will grab the default alsa device. What I do is change
the order of card module loading. This is done in
/etc/modprobe.d/alsa-base.conf

There are two ways (according to on line documentation). One is to change
the:
install sound-slot-0 /sbin/modprobe snd-card-0
install sound-slot-1 /sbin/modprobe snd-card-1
etc.

Lines and put snd-usb-audio where snd-card-0 is. I have not gotten that to
work for me. What I did instead was tell the unwanted card to load last.
Farther down in the file there are a bunch of lines with index=-2 at the
end. I added these lines:
# ensonic should not be first
options snd-ens1370 index=-2

I notice this next line is included twice (ubuntu 12.04):
options snd-usb-audio index=-2

You may want to put a # as the first character to comment it out. Then add
a line:
options snd-hda-intel index=-2

It would also be worthwhile finding out why pulseaudio doesn't see the card.

-- 
Len Ovens
www.OvenWerks.net