Tweaks when building a listening room?

I know its not cheap, but have you considered using the spray foam insulation ?

We did the whole house ( outside walls / attic ) last year with this to save money and it also did a good job of I guess you could say soundproofing the house.

If interested, contact me and I can send a link and it will show a video of the work that was done.

I recently finished a dedicated 2 channel room and used double 1/2 inch drywall and all walls were double insulated before the drywall went up. I too brought in two 20 amp circuits and two 15 amp circuits for power.

The best tweaks you'll make will be after the room is finished using room acoustic panels.

If you are considering a dedicated circuit: Use(as least) two runs(keep 12" separation between the two) of 10-2 Romex(equiv of 4Ga), and(minimum) hospital grade outlets(ie:http://cgi.ebay.com/Leviton-Ivory-HOSPITAL-Receptacle-Outlet-20A-8300-I_W0QQitemZ250202544990QQihZ015QQcategoryZ41985QQcmdZViewItem). Also- Consider Auralex, or some of the substitutes available on eBay, to deal with the reflections inevitable in a listening room. Click on topics: (http://www.asc-hifi.com/acoustic_basics.htm) (http://shop.ebay.com/items/__acoustic-foam_W0QQ_nkwZacousticQ20foamQ20QQ_cqrZtrueQQ_nkwuscZcousticQQ_nkwuscZfoamQQ_trksidZm38)

Thick carpet, bookcases, thick drapes over windows, sliding doors, and upholstered furniture will all contribute to improved bass extension, soundstage, and overall fidelity. Avoid openings to other rooms without doors. Keep the doors closed to keep the sound in. Enjoy !!

Prior to my listening room remodel, I contacted Cryo-Nebraska who in turn locally purchased 500' of 12 gauge and 14 gauge romex at their local Home Depot, double-cryo-treated it and shipped to me which was then installed for my 4 dedicated lines.

A few other tidbits include premium wall-to-wall carpet with premium pad, few windows, no hard-surfaced furniture including tables and leather, and recessed lighting.

These few basics, good room dimensions, and proper speaker placement should be all you need for a superior room.

For everybody else in the house and neighborhood I suggest insulating all walls.

-IMO