[John Jordan]

Lars-

Well...off the top of a junkyard dog's head...

1. it is my understanding that concrete floors make for great audio rooms.
2. if your breaker box is in the basement, separate circuits or even a dedicated sub panel are more easily achieved.
3. Is A/c really needed in the basement?
4. dehumidifiers can be shut off while listening. Are you doing stand alone units or something more potent, similar to an a/c unit?
5. for doors, consider solid core.
6. Walls can be insulated but sound travels through floor joists/wallstuds so perhaps a false wall or double sheet rock?
7. placing damping pads under appliances (furnace/dehumitifier) will quiet them. Check out Supply house on Long Island.
8. Pick and choose but take all with a grain of salt.

good Luck with this Project1
Keep us informed!