1) Does MMA support Replay Gain? The user manual doesn't explicit state this, only that it's
an excellent approach for PC-based players,
2) If the answer to 1) is yes, how do you switch it on in MMA? The user manual only discusses the PC based playerReplay Gain
This is the most standardized approach to volume leveling, providing a comprehensive approach for all audio formats without impacting audio fidelity. Replay Gain implementations use a multi-phase approach: first track volumes are analyzed and the resulting coefficient is saved to the track's tag (Track gain). Then after all tracks on an Album have been analyzed, a single coefficient is saved for all tracks on the album (Album gain). Then, during playback, the Album or Track gain tag is read and the player adjusts the volume up or down accordingly (Album gain is preferable for playing an entire Album and preserving the inter-track volume variances encoded in the original album, while Track gain is preferred for playing a playlist of tracks from various sources). This is an excellent approach for PC-based players, but is limited because many portable devices do not support Replay Gain tags, and thus when tracks are synced to a device, the volume will vary.
MediaMonkey supports Replay Gain analysis and playback (per Track and per Album via 'Analyze Volume' and 'Level Playback Volume').