Never choose this device as the default output

[Chris Keller]

Hi folks,

I'm using an amatuer radio audio interface called a SignaLink USB; it
presents itself as an external sound card and can send and receive audio
through the radio. It's working well, but every time I plug it in, the OS
picks it up and assumes that I'd like to use the external sound card as the
default and starts playing all system sounds through the radio.

Is there a way to configure ALSA to not use the SignaLink as the default,
ever? Ideally this would only apply to the SignaLink, but I'd settle for
having the system never automatically change the default sound output and
always manually changing it as needed. I've tried using .asoundrc to
specify a default, but that didn't seem to have an effect.

Chris Keller (K0SWE)

[Chris Keller]

With some help, I was able to identify a solution. It's PulseAudio that's actually doing hotplug support on my system, so I was able to disable hotplug behavior there.

In /etc/pulse/default.pa, find and comment out lines related to module-switch-on-connect:

#.ifexists module-switch-on-connect.so
#load-module module-switch-on-connect
#.endif

Now the default audio sink won't change automatically, it must always be done in pavucontrol or the system volume widget.