PulseAudio

Depending on which applications you use, you might need to provide PulseAudio with a D-BUS session bus (e.g. via dbus-run-session) or a D-BUS system bus (via the dbus service).

For applications which use ALSA directly and don't support PulseAudio, the alsa-plugins-pulseaudio package can make them use PulseAudio through ALSA.

The PulseAudio package comes with a service file, which is not necessary in most setups - the PulseAudio maintainers discourage using a system-wide setup. Instead, PulseAudio will automatically start when needed. If it is not starting automatically, it can be started manually by invoking pulseaudio(1) from the terminal as follows:

$ pulseaudio --daemonize=no --exit-idle-time=-1

There are several methods of allowing PulseAudio to access to audio devices. The simplest one is to add your user to the audio group. Alternatively, you can use a session manager, like elogind.