140 ft? It would most likely be less expensive to add a 30 amp sub-panel close to the music room. You could run a single 6 ga Aluminum or 8ga copper line to there and then 3 shorter lines to create the circuits. It would also leave you room for more circuits at a much lower cost per circuit in the future.
That solution would also leave available one more slot you have in your existing main panel in case you need new circuits to originate there.
That solution would also leave available one more slot you have in your existing main panel in case you need new circuits to originate there.