If you have a six-breaker panel with six 20-A breakers installed then you have no choice as to the phasing; the panel is full and you cannot - at least never attempt to - reconfigure the panel.
Word of caution: overloading one phase of a 120/240 leg can cause problems. The whole idea of having two balanced phases is to prevent neutral currents. Things like computers and fluorescent lights generate current themselves on the nuetral; having the phases out of balance magnifies the problem, not the least being a fire haxard.
I'm not saying you cannot have your audio gear on one phase or both phases - but whatever you choose just make sure both main feeders coming into the panel draw an equal amount of current (within 10%) with your audio gear on and with the other appliances operating normally.
Word of caution: overloading one phase of a 120/240 leg can cause problems. The whole idea of having two balanced phases is to prevent neutral currents. Things like computers and fluorescent lights generate current themselves on the nuetral; having the phases out of balance magnifies the problem, not the least being a fire haxard.
I'm not saying you cannot have your audio gear on one phase or both phases - but whatever you choose just make sure both main feeders coming into the panel draw an equal amount of current (within 10%) with your audio gear on and with the other appliances operating normally.