RPi3 Allo BOSS and SoX settings

[Tim Curtis]

For audio devices that have on-chip Hardware volume controllers you will have two volume controls in the audio chain. The first one is MPD's software volume control and the second is ALSA's volume control which represents the on-chip volume controller.

The three valid volume configurations are:

1. MPD Disabled, ALSA 100% (MPD outputs 100%)
2. MPD Hardware, ALSA % varies with MPD volume setting (MPD is varying the on-chip controller)
3. MPD Software, ALSA 100% (MPD controls volume with its software algorithm)

The Disabled and Software volume control settings require ALSA volume to be at 100% (0dB) so the overall system volume is 100% (0dB) when MPD volume is 100%.

You can change ALSA max volume to be < 100% via the setting on Audio Config.

-Tim