The change I'm asking is not mainly for myself. I manually adjusted those volumes to match the arcade. No problems there.
Problem is, MAME doesn't offer a proper rendition of the game, and that's the way everyone is experiencing the game.
One of MAME's goals is to keep old games from falling into oblivion and it's a shame that MK will be remembered as having that horrible bass drum all over it and people muting its sound to play.