How do I configure PulseAudio to use only a single ALSA device for input and output?
The default PulseAudio configuration causes PulseAudio to open all ALSA devices when it starts. This makes it impossible to use PulseAudio together with other ALSA clients. Many people prefer PulseAudio to ALSA, but other users find it frustrating. For better or worse, PulseAudio has become a standard and several popular Linux applications, such as Skype and Firefox, only support audio output via PulseAudio.
Some users prefer to work with audio clients that output directly to ALSA, others output to another audio framework like JACK, but want to have JACK access ALSA directly. For these users, it is easy to free up all the ALSA devices by uninstalling PulseAudio. However, removing PulseAudio makes it impossible to use audio in Skype and Firefox.
A better solution would be to come up with a configuration that gets PulseAudio to "play nicely" with other ALSA clients, outputting to only a single device, which would be specified in its configuration, or even just the ALSA
default device. How can we do that?