Dedicated Line Advise

Lowrider - The box you have is just another variant of a two phase supply.

The electrician will simply use two switches and ensure they are on the same phase - e.g. switch positions 7 and 8 or 9 and 10 (assuming they are available.)

It does not matter which phase they are located on, as long as they are both on the same phase.

Some people believe having outlets on different phases do not improve SQ - HOWEVER, from a safety perspective, havin all components on a single phase is safer should one component fail, there is no risk of exposure to voltages across two different phases, which is much more dangerous

Placing the new breakers at position 19 & 20 will ensure they are located as far as possible from the noisy appliance breakers.

A separate breaker panel just for the audio circuits might be the quietest solution - but more expensive

Regards...

Many thanks, williewonka.
You've provided valuable information.

Your mixing phase and leg. There are one 2 legs split from one phase.
Read some of these replys to the phase question, they are in layman terms.
http://www.hobby-machinist.com/threads/why-is-220v-called-single-phase-when-it-has-two-phases.17428/

russe41,
So, then the proper way to wire 2 dedicated lines is to have them both on the same leg, yes?
In my case, breaker #1 and 2 are on the same leg. Am I correct?

BANK "A"           BANK "B"
Switch #               Switch #    
1               A             2
3               B             4
5               A             6
7               B             8
9               A           10
.... up to # 20

Lowrider, somehow I lost tract of your post and not responded. However seems you have gotten the info you requested, and more, from those that are far more knowledgable than I. Lots of great info here, thanks for the post. As pre willie, I have my audio lines at the bottom of my box and the dual phase breakers at the top.