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I have a computer acting as a sound server, managed by Pulseaudio. All computers on my LAN send sound to that machine. It has a Kenwood digital audio device connected to it.

When I open pavucontrol on that sound server, it looks like this:

Volume_Control

So far so good. The GF108 is, as I've learned, a sound controller on my Nvidia card, and the Built-in Audio is the motherboard's sound chip, and the Kenwood Audio Device is the one I want to use.

However, when I click on the Profile: option, I get this pop-up menu of options:

Audio_options

Why does this one device have 15 different options, and what is the difference between them?

I have, of course, tried different ones, and they all seem to work. Why would I select one over any other?


Additional note for some context: My motivation for looking into this is that currently my sound set up has two problems. One is that it can't play more than one sound at a time - any app that is playing a sound takes exclusive control, and starting a sound in a new app causes freezes or crashes. My sound setting used to be able to play multiple streams so I think this should be possible. The other problem is that volume settings are hard to control.

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1 Answer 1

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These control the channel map pulseaudio uses for your device.

Pulseaudio has some standard names like "left", "right", "center", and so on for audio channels. Applications also output on channels like this. Pulseaudio then remixes the audio as needed, and tries to do the "right thing". For example, if an application is outputting a "center" channel, but your output device doesn't have one, it will mix it equally to the "left" and "right" channels.

The profile setting here determines how Pulseaudio maps its channel names to the underlying (usually ALSA) device channels. Usually which you select will depend on what kind of speakers you have and how they are connected. You can see the profiles also affect the input channel mapping, so many of these are just different combinations of input and output mappings.

You can see the channel maps in effect with commands like pactl show-sinks and pactl show-sources.

You can define more profiles in /usr/share/pulseaudio/alsa-mixer/profile-sets.

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