Best way to keep piano finishes looking great is to not contaminate them with fingerprints or other contaminants in the first place. Your speaker finish will never need more than a dusting if you are careful. Whenever I have to move my speakers (which is hardly ever), I put on the white gloves that came with my Prima Luna preamp. This avoids getting fingerprints on the finish. You can use something similar. After that, only a light pass with a feather duster keeps my Tritons looking brand new.
J.Chip
J.Chip