I really enjoy music while gaming and often refrain from it to avoid needing to keep multiple programs running and having to fine-tune ingame soundscape with external music as it can be inconvenient. A feature that lets the player add custom tracks to an audio playlist ingame would be awesome as it could follow the volume bar of the music while not disturbing the need to hear visual cues in-game.

Both by mod and as a ingame feature this would be cool, but having it as an ingame feature would be optimal as I prefer being able to join unmodded servers.

Music already ingame is fine - But I always get tired of ingame music very fast no matter what game I play..