I want to do a simplest thing possible in ALSA: to have USB-headphones produce sound instead of internal speaker of my tablet. I don't want to change config files such as
asound.conf and permanently set headphones as default output device by changing the order of devices, I want a temporary effect, just until I unplug the headphones. Strangely, I can't google the answer. Is
alsamixer capable of doing that (seems like no)?
In Gnome you can easily select current output device with
PulseAudio, either in its GUI or CLI interface, but
PulseAudio itself works on top of ALSA! So I also wonder, how it forces ALSA to change the output device?