Declicking, Enhance Sound or Surround... what part of that don't you understand? AFAIK, only the VBA-M emulator has those features in it's sound settings. This is the exact reason why I'm converting GBS to GB.
I like the Enhance sound and surround sound things because it defaults the 2 square channels to left or right panning, and the other channel has a surround effect thing, because mono sucks.