[SOLVED] Replay gain

[DRONE7]

Like many I have a mixed Library of sources, years,  and differing file types.
Recorded levels are thus quite variable and, having tired of manually adjusting, I spent some time adding replay gain tags.

Used rsgain as it handles a very wide range of formats including .wav.
Only to find that MPD has a limited range of file support and .wav is not one. No bother, will just convert the few .wav to flac.

However, I am unsure as to how MPD handles the volume adjustment...perhaps someone can illuminate ?

From the MPD documentation

ReplayGain is usually implemented with a software volume filter (which prevents Bit-perfect playback).
To use a hardware mixer, set replay_gain_handler to mixer in the audio_output section (see Configuring audio outputs for details)

To configure an audio output manually, add one or more audio_output blocks to mpd.conf:

audio_output {
    type "alsa"
    name "my ALSA device"
    device "hw:0"
}

ProtoDac has no mixer and I have volume Disabled so 0db output.

mpd.conf contains

Code:

replaygain "auto"
replaygain_preamp "0"
volume_normalization "no"

and audio output section there

Code:

audio_output {
type "alsa"
name "ALSA Default"
device "_audioout"
mixer_type "none"
dop "no"
stop_dsd_silence "no"
thesycon_dsd_workaround "no"
}

Listening confirms replay gain is operating but what is MPD using to make the adjustment ? Software Volume ? if so where is that configured ?