Advantage using one electrical leg for audio system?

@jea48 , then is the way OP did it

The OP has a 3 wire multiwire branch circuit. He’s stuck with what he has. He has two separate circuits that must be fed from both legs that share a common neutral conductor.

preferable to running two circuits of 10-2 with two separate neutrals?

And on edit:  what would be the reason/advantage for using two runs of 10-3 vs two runs of 10-2?

Thanks for the clarification, @jea48  .

NO..

Two 10/2 with ground Romex cables fed from single pole breakers fed from the same Line, Leg,... IS Much, Much, better than what you have now...

Actually I am presently running my gear on three runs of 12-2 fed from single pole breakers fed from the same Line, Leg.  I am still intending to get some type of strip that I feel I can live with to experiment with running off of only one circuit.