Building an audio room - 12x22 - electrical plan?

Running 220/240 single phase into a dwelling is not an issue, but there are probably restrictions on the type of room, e.g. a bedroom, you can run it to. This should be checked with the local building inspector. I concur with S7horton about the availability of 220 VAC 60 Hz equipment, very few if any. My only recollection of a 220 VAC unit was a Very high current amp a few years back in a show report. An important comment on European equipment, it is designed for 50 Hz and won't work on our 220 (60 Hz). You would need a transformer or power regenerator to use it.

Here

Above link to an earlier discussion about this subject JEA48 gives excellent advise on the code issue of 220V outlets in a residential setting.

As far as running stereo equipment on 220V / 60Hz it is actually easier for a transformer to run on 60 Hz than on 50hz and most of the equipment will happily run on 60Hz. In most equipment the AC signal is rectified as soon as it enters the machine at which point the AC line frequency is irrelevant. If the transformer have multi winding primaries its only a matter of running these in parallel for 117V operation and series for 234V operation.

Some of the larger companies that wish to control where their equipment ends up do build some frequency monitoring devices into their stuff to prevent its use in other markets than originally sold. However without these the equipment would happily work on either 50 or 60 hz.

Good Listening

Peter

You'll probably need Arc Fault Circuit Interrupter breakers for each circuit.

http://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter

I just did my 10x20 room. I had one outlet for AC and lights, one just for audio that has 8 outlets. Besides all the suggestions, one thing I wish I should have also added was running 2 sets of opposite phases into the audio outlet for noise cancellation.

Pay particular attention to the construction phase for quality work. If you can stagger the studs with any common walls that would help with sound isolation. Also seal any air gaps with acoustic calk such as baseboards, outlets etc. Sound will travel!