Ubuntu Touch uses Pulseaudio as sound server. Documentation can be found at and in the Ubuntu manpages

The default configuration file used on Ubuntu Touch is This file is located in the /etc/pulse directory on your device and it will need adjustment in order for sound to function properly. Extract the file and copy it to the ubuntu directory you created in your device repo (see Overlay file method).

Locate the line:

load-module module-droid-discover voice_virtual_stream=true

and replace it with this:

load-module module-droid-discover rate=48000 quirks=+unload_call_exit

At the end of the file, append this:

### Automatically load the audioflinger glue
load-module module-droid-glue-24

Your modified file now needs to be included in your build. Follow the overlay file method corresponding to your Halium version.