basement studio with high ceilings

Hi everyone, This is my first post. I've read a ton of great info from these forums but still have some questions about building a studio for rehearsing/recording my loud rock band (drums, bass, 2 guitars, vocals). I'm renting a loft in the basement of an old church converted to an apartment building (Downtown San Diego, CA) that has a separate room with dimensions as shown in the picture. Floors are concrete, walls are 12" thick concrete (painted but with cracks, holes, etc), and the drywalled ceiling is 18' high (not sure if there is insulation behind it). The 3' by 3' "notch" is the corner of the entire building. The wall on the right side has earth behind it, up to about 9', then an alley for the remaining height. The angled and bottom walls have my living area and kitchen behind them respectivly, and the top wall has an outdoor stairwell behind it leading up to a parking lot on the ground level. The stairwell wall and the earth/alley wall both have 1 window each about 9' above the floor. There is about a foot between the top of the windows and the lowest pipes protruding from the ceiling. There is also a 6" x 6" post as shown in the picture. Currently the doorway has no door. I've already received a complaint from our upstairs neighbor when we tested the room (bad decision). However, there is a rap group next door to him that rehearses regularly and another loft with a skate ramp next door to us. Granted, these are not nearly as loud as a full-on band, but there seems to be some tolerance within the building. Maybe the sound going straight up is my major concern? Anyway, I have about $2000 to $3000 to spend on materials (labor will be me and my bandmates). At first I thought a floating ceiling just below the windows (along with capping the windows and installing solid double doors) would be enough but after reading more about it, it seems a room in a room might be the way to go. The space is a lot bigger than what we need so I don't have to go wall to wall with the constuction. Also, I don't want to add anything to the existing concrete walls because that's a lot of square footage to fix. If I build a room with double leaf walls do I need to be a certain distance from the existing walls to avoid a triple leaf effect? If I build the room to a height just under the windows, will the extra space between the room and the ceiling cause any resonance problems? Should I isolate the room from the floor, even though it's concrete and in the basement? There seems to be a lot of options and I need some help deciding which way to go. I hope I've given enough detail. This forum is amazing. I know there's a lot more for me to learn. Thanks, Chacho

Hey Chacho... I'll take a couple feet of that ceiling height from you, if you can spare it, lol... I can only dream of having such a high ceiling in my basement... :( Is that 18 feet mostly below or above the ground? Are the interior side walls also concrete, 12 inch thick? (ahh, here I can empathize; I also have 12 inch thick (actually more like 14 inch thick) concrete walls... but only on the exterior) And, how can you have a basement 'loft' ?... isn't that like an oxymoron or something? totally jealous of your ceiling height, K

The 18 feet has about 9 feet of it underground. Well, at least the side where the alley is and part of the stairwell side. The interior walls are concrete. The opposite sides that face the living room and kitchen have drywall and 2x4's (from what I can tell). I guess "basement loft" is prety oxymoronic, but that's how it was advertised, so it stuck. Actually, curiosity just forced me to check Wikipedia, which defines it as "A large adaptable open space in a factory, warehouse or other commercial space, or a type of residence that results from the conversion of such a room. Such spaces generally contain very high ceilings, large windows, and concrete floors and ceilings." Mine just happens to be in the basement.

OK, so I'm still reading and learning new stuff everyday. The approach I'm thinking of now is to use the concrete walls as the outer leaf on two walls of the studio (see first pic). The other two walls will be offset from the existing walls 3 to 5 feet and will be double leaf drywall with RC but will extend all the way to the concrete walls (not touching but with caulking or some other flexible seal in between). The second picture shows the intersection of the two different walls. The ceiling frame will attach to the wall frames and also extend to the concrete wall as shown in the third picture. This will create a connected air gap that completely surrounds the studio (except for the floor). Considering the weakest link rule, the outer drywall must be equal to the top plywood/carpet (in terms of isolation). I don’t think this is the case. Would a layer of vinyl or GAF Tri-ply over or under the plywood do the trick? I don't want to use drywall because I want to be able to walk on and utilize the "roof" of the room. I am assuming the concrete-air-frame-RC-drywall provides the most isolation. Is the RC on the frame along the concrete walls even necessary? or would this be overkill since there is already isolation between the frame and the concrete walls?