I'm sure there will be a GUI way to switch the default but I tend to use environmental variables when I want to launch a program out of a non-default device
>Is it possible to use/set environment variables to change the default ALSA device?
>you can use ALSA_PCM_CARD or ALSA_CARD to set the default card, either by name or by number. If both are set, ALSA_PCM_CARD takes precedence. The device on the card can be set in the variable ALSA_PCM_DEVICE.