configure the recording volume

[schmeic]

Is your feature request related to a problem? Please describe.
When I save files as mp3, the volume is very low. I usually have my volume around 30% when playing directly from the Spotify app, but when playing the mp3 files, I need to turn the volume up to around 80%.

Describe the solution you'd like
It'd be nice if there was a config option to set the volume level, similar to the lame --scale option.

Additional context
Nothing else to add.

[airone01]

For context, the client app has additional support for standardizing audio level.