I was considering that the in-game Gramophone is more for the user during game play. More realistically, I am certain that it would not be used in silent running situations, except for the last ditch morale boost.
The Gramophone sounds are not a factor in the escort detections in SH3.
Maybe an occasional needle skip that occurs while cresting a wave as you travel on patrol would be more suitable? Also, maybe a Gramophone shut-off order on silent running? Just some thoughts.
