I'm starting to poke around for a new home.
 
Looking for a place where I could have a drummer and sax player without disturbing my wife and kid turns out to be a trick.
 
So often there is a nice upstairs room above a nice downstairs room. If my wife and kid are watching TV in either and I have a band in the other, they will have no peace.
 
So what I'd like...
-- A nice big room away from the other main living spaces
-- good power and sound-proofing
-- easy way to carry gear in and out
 
I partly feel that just keeping a little office room with my gear in it and pulling my gear out when people come over is the best way to go. In my current home, I have a little room over the garage that has been great. I get as many as 5 others up here (very tight) and record. The room is on the opposite end of a ranch house from the bedrooms so there is good isolation. They can hear us, but it's tolerable.
 
Mostly, I'm mobile and go out of the house to record, but I regularly have 2-3 people come over and it's nice to be able to host.
 
I'm posting this mainly because it isn't that common of a problem. I'm not sure how other folks solve it or what they look for. Budget definitely matters. My wife and I have turned away from probably 50 possibilities because we couldn't figure out where the music might happen. 
 
Garage is an obvious suggestion, but my wife has an electric car that needs plugging in at night.
 
Thoughts?
 

I like to look on Craigslist.  I search under homes for sale with key words like *studio* or *bonus room* or *media room*.  You'd be surprised at what comes up (depending on the level of artistic activity in your town.) Portland, Seattle, Nashville, Austin and of course the big cities you'll have quite a bit to choose from.  Good luck!

garage.. and get her an extension cable ;-) or outside plug.
 
thing is , if a car uses it has an impact on the security.. I know a sisters neighbour had a drummer.. and they built a shed for it...

Since you are buying you could also think "room in a room" for proper isolation.
 
Don't know how skilled you are and what your budget is ... and also the room needs to be of a certain size to get this to work, but there are studios like that in the middle of apartment towers (e.g. I've seen youtube videos where Moby talks about his room in a room where he records drums at night time)
 
I tried to follow the "room in a room" concept as much as possible (room height was an issue so I could not get the recording room fully "floating" in the existing room). Yet, I obtained enough isolation so that with a rock drummer blasting, you can watch TV at normal levels in the room right above. Ditto in the control room next to it ... a little bit of kick drum and snare spill which is only noticably with monitors off.
 
So IMHO, it's mostly up to your skills and time budget (mine took half a year to plan and about 8 months to build as you need to think a good deal about things like wiring and future needs as well ) ... of course it also costs some money but compared to what you will pay for the house this is probably peanuts.

Depending on your budget and the property values where you're looking, the may not be an option. But I think the obvious answer to having a room for loud instruments whilst not disturbing the family in the rest of the house is to make sure that room isn't in the house. What you want is an out building like a pole barn. Run power to it, insulate the bejesus out of it and bob's your uncle. 
 
Like I said, might not be an option where you live. Where I grew up in rural NJ, properties with existing pole barns (or even enough land to build such a thing) were a very rare commodity and sold for top dollar. OTOH in places like rural Michigan, they're a dime a dozen. 

But even if a pole barn or some other type of unattached garage isn't in your future, don't rule the idea out completely. I've got friends back in NJ who solved their band rehearsal space dilemma by going to Lowes and buying the one of the largest prefab wood sheds they had. I think they come as large as 12x20. Run some power to the back yard and boom, studio in a box. 
 
If an out building isn't possible, then your next best bet would be a house with a large wide open poured concrete basement. Preferably one with a ceiling around ten feet. Then as was previously suggested, you build yourself a room within a room. If recording is your goal, then you really want to think about building a couple of rooms within a room within a room. IOW a large main studio space with insulated floating walls, floor and ceiling. And inside that large main room, a couple of smaller rooms which have their own insulated floating walls, floors and ceiling. It won't be cheap, but it'll be quiet. Oh and HVAC will be a challenge to say the least. Good luck in your search. 

Oh, I forgot about barns and out buildings.  The other thing you can search CL for is a *shop*.  That'll have all the right amount of electricity for you.

out building is probably the easiest, although you'll still want to add some isolation.
 
Next up is the basement, especially if the basement is below grade. Having the earth adjacent to your walls provides quite a bit of isolation, so that the only remaining path is the ceiling, and that can be enhanced without having to do the whole room-in-a-room thing. There are dozens of case studies on the web.

The garage option with extension would be my choice as well. To truly soundproof a room you will want dampening material inside the walls/ceiling/floor and few get upset gutting a garage or adding to it since much is already accessible. Normal garage doors won't cut it though.

Soundproofing inside the home would also need ceiling/floor done, and few homes have anything but air between the floor joists.

Basements are my favorite. Best if they are unfinished when you take possession.  
Then you can insulate the ceiling and sound proof. 

I went through this scenario about 12 years ago. I ended up with an unfinished basement. With a lot of research I learned that it takes mass and isolation to keep sound from traveling throughout the house. I installed isoclips with hat channel (metal furring strips) on the ceiling, rearranged some ductwork, insulated between the joists and the screwed two layers of 5/8" drywall for the ceiling. Built a 6" wall with staggered 2"x4"s so each side has it's own studs, insulated it, double 5/8" drywall on each side and installed an insulated exterior door.
When it was done I could rehearse with the full band, drums and all at full volume when the wife and little dude were upstairs watching TV. It's well worth the time and investment.
 
Rocky