My idea (I'm not a metalurgist and I didn't design your breakers)of why your 100 amp breaker sounds better is due to the construction of the breaker with it's bimetallic strip and contact surfaces both of which would be larger in a 100 amp breaker. For your safety and to stay code approved (6 gauge is still way to small for 100 A) you're going to have to put in some current limiting device somewhere before your amplifier. A simply constructed (not slo blo) cartridge type fuse may be a good option.
Besides a commercial electrical contractor you might want to contact mega buck home theatre specialists (in your area) for who they sub contract the electrical portion of their installations. Commercial contractors mostly use smaller fuses for motor protection, not specialized audio installs.
Besides a commercial electrical contractor you might want to contact mega buck home theatre specialists (in your area) for who they sub contract the electrical portion of their installations. Commercial contractors mostly use smaller fuses for motor protection, not specialized audio installs.