Re: [gentoo-user] ALSA wizard...

[Jorge Almeida]

On Thu, Apr 23, 2020 at 9:19 AM Michael <confabulate@××××××××.com> wrote:
>
> I recall you having problems recording with this device before, but since
> you're now a step ahead let's have another go at this, in case I may be able
> to help.

Yes, this is not the same issue (the former problem was: I wasn't
getting anything from the RCA output; maybe it isn't supposed to--no
documentation provided with the device--or that part is broken;
anyway, I gave up on the RCA; the device works fine as a USB sound
card)

>

> > > The setup:
> > > -- a microphone connected to an audio interface, which connects to an
> > > USB port in the computer. The interface works like a USB sound card,
> > > at least regarding sound capture. It works: I can record my voice with
> > > arecord into a wav file, and then play the file with aplay.
> > > -- a (motherboard) sound card with a toslink output connected to an
> > > external DAC/amplifier. It works: playing wav, youtube, etc.
> > >
> > > The problem:
> > > I need to use it for voice chat. I tried slack and discord (the latter
> > > both via browser and app--there's a package in portage--, the former
> > > only via browser). No sound, neither outbound nor inbound.
> > > None of these programs provides a way to tell them which devices to
> > > use, so I assume they just go for some default.
>
> Yes, this is the case or you're missing some audio module/driver/firmware,
> which is probably unlikely for a device which presents itself over a USB
> interface.
Yes, and the device works for recording; the playing together with the
other card (for output) is the problem, which I believe is a matter of
having an appropriate .asoundrc (the syntax of which beats me)

> If an application like vlc allows you to get audio output by
> switching devices, then you know you will have to change the order of your
> cards as they are detected by the kernel.

the kernel consistently detects the MO card and the USB card in the
same order (MO: card 0, USB: card 1).

>
> QUESTION:  I am not familiar with your hardware, but is dmesg *only*
> identifying it as a USB device?  I'm asking this because you may need to
> additionally configure e.g. a serial/parallel interface to the device for
> controlling it, or at least adding yourself to some user group, if USB alone
> won't suffice.
>
[  726.441114] input: Burr-Brown from TI               USB Audio CODEC
 as /devices/pci0000:00/0000:00:14.0/usb1/1-10/1-10:1.3/0003:08BB:2902.0005/input/input21
[  726.492970] hid-generic 0003:08BB:2902.0005: input,hidraw3: USB HID
v1.00 Device [Burr-Brown from TI               USB Audio CODEC ] on
usb-0000:00:14.0-10/input3
[  726.493002] usb 1-10: authorized to connect


I'm in the group "audio" and the permissions of /dev/snd/* are right (0660)
>
> > > I don't have a .asoundrc file. Contents of /etc/alsa/conf.d/ are not
> > > customized.
>
> OK, this is noteworthy, you may need to do some tweaking in such a file,
> depending which audio card is detected first and what controls are made
> available.



> > > sysdefault:CARD=PCH
>
> OK, this shows your audio card on the MoBo is picked up by default as the
> first card.
>
>
> > >     HDA Intel PCH, Generic Analog
> > >     Default Audio Device
> > >
> > > front:CARD=PCH,DEV=0
> > >
> > >     HDA Intel PCH, Generic Analog
> > >     Front speakers
> > >
> > > usbstream:CARD=PCH
> > >
> > >     HDA Intel PCH
> > >     USB Stream Output
> > >
> > > sysdefault:CARD=CODEC
>
> This is what you want to configure as the default audio device.

Only for capturing, not for playing!




>
> In the first instance create a new file (for system-wide settings):
>
>  /etc/asound.conf.
>
> Add in it:
>
> defaults.pcm.card 1
> defaults.pcm.device 0
> defaults.ctl.card 1
>
> which hopefully will make your second card configured to be the default.

But that will make the USB card the default for both input and output.
The USB card should take care of the input (microphone) and the MB
card should deal with the output (digital signal sent to external
DAC/amplifier via toslink cable).
>
> More detailed settings and tweaking can be found here:
>
> https://www.alsa-project.org/main/index.php/Asoundrc

I know that page. It doesn't give a hint about how set defaults with
input and output through different cards.
>
Thanks

Jorge