/etc/pulse/default.pa: Permission denied

The recommended way to create a user-specific default.pa file is working on a copy in the user's HOME. This copy should be stored in ˜/.pulse or ˜/.config/pulse whichever directory already exists.

When running pulseaudio in userspace (this is the default) settings we had made in this file will override the system-wide /etc/pulse/default.pa on the next restart of the pulseaudio sound server (e.g. with pulseaudio -k).

Only if system-wide settings need to be made for all users we may edit /etc/pulse/default.pa with root privileges. Then we should take care to make a backup copy of that file to be able to revert to the default settings in case something went wrong.