Have I done this all wrong

Hello. Great forum - wish I'd found it sooner! 3 months ago I started work on converting a single story terraced industrial unit into a small studio here in West London, UK. The live room measures 5m x 4m, and the control room 7m x 4m. The building is brick walls and concrete floor. The walls are brick inner, 4" cavity and brick outer. The roof is a weak point, basically hardboard and bitumen on timber rafters (I had been told it was concrete, but its not!) I had some mis-information when I started the live room work, and as a result it is not a "room within a room". It has 75mm Rockwool (RW3), resilient bars and 2 x layers of 12mm thick gypsum green glued and caulked. Therefore the walls all round are 2xlayers green glued drywall on bars with rockwool before the 9" brick cavity walls. The ceiling at the moment is 2 layers of 12mm drywall, green glued and caulked, with 75mm rockwool and then the top hardboard and bitumen. The dividing wall between the live and control room is 3 layers of GG'd drywall on resilient bars one side and 2 layers of drywall on the other. The window is 2 x double glazed units (4 layers in total). Problem is drums are still way too loud for the neighbours. Kick drum and cymbals are the main problem, toms and snare are pretty well dampened, although the room has no internal acoustic treatment just yet - didnt want to do anything until I was sure enough plasterboard was up. What more can I do without running up huge costs to combat the noise? I think most of the sound leakage is from the control room side - as too much noise is passing through the dividing wall, but the kick drum really thumps and can be heard 3 neighbours down. Budget wise I guess up to £1,000.

Hey man. I hate to say this but it sounds as if there really isn't going to be a cheap way to fix your problem. It's no mystery that the kick drum sound is your biggest problem. That's because lots of mass and properly decoupled room within room construction is needed to stop low end and bass. It sounds like you may have actually created some resonance issues because of the way your room has been built which actually amplify low end sounds. If you're willing, there are many on this forum that can help you fix the problem as long as you provide enough info and are patient and are willing to spend the extra cash.

you may have a three leaf system because of the 9" brick wall cavity and the additional wall layered on the live room side. you might also have flanking from the floor and/or ceiling beams. if you take a hammer (metal and rubber ones) and tap on the floor (and if you can access them - the beams) in the live room, what is your neighbor hearing? also - what about AC duct work? is this shared? any openings through the roof area what would let sound conduct across the ceiling?

There is no ac ductwork, and no openings in the ceiling which should overly transmit sound to the neighbours. Each unit is pretty much contained. The floor in the live room has an extra 3" of cement than the live room and hammering on the floor hasnt caused any noise to transmit next door. I think the ceiling is probably the weakest area, particularly for flanking into the control room, and out that way. Is the cavity wall and drywall mass enough theoretically to contain drum noise, or should I really be adding a new room within room. I guess financially I have to do what it takes having spent 3 months working on it and paying the rent. All advice gratefully received - if you need any more details please shout.

just curious - what happens if you play the drums and bass in th control room?

Is there anything I should be thinking of, other than retrospectively building a new room within a room? The pictures below at the early stages show what I've done in terms of rockwool, bars and plaster against the primary walls and the initial layers going up on the ceiling. The view into what is now the control room has the suspended ceiling in place. Havent tried music in the control room yet as all my efforts have been in creating the live room and trying to isolate it as much as possible. There is still a big single window in the control room which is being replaced this weekend so no point in trying any type of noise in there as it will just leak out.

When I go outside to smoke I usually listen to the Alabama game thru my closed window. I think your neighbors are doing that too:) Is there a wall that goes all the way to the "roof" in between the rooms in question? Up to the ceiling isn't going to be as effective as it looks more like an open cavity(overhead ceiling) that allows sound to move about freely unhindered. I also suspect you are correct in that the roof membrane is of no use as it pertains to isolation as it is. But those windas'... Brien

I think there is a solid wall between units - put it this way, I can hear nothing from either neighbour even up a ladder listening close to the wall and ceiling. The window has been sealed, acoustic tiles and rockwool put into the gaps and plasterboarded over well and truely. On the otherside it has had MLV barrier mat glued to it, then filled with rockwool and hardboard sealed over it. Actually the sound leakage through the window is a lot less than I was fearing and its almost as good as the wall.

xSpace wrote:

Is there a wall that goes all the way to the "roof" in between the rooms in question? Up to the ceiling isn't going to be as effective as it looks more like an open cavity(overhead ceiling) that allows sound to move about freely unhindered. Brien

You are right in that the dividing wall for live and control room goes to the ceiling, but there is now heavy T3 Membrane (barrier mat with padding) nailed to the joists and creating a barrier for air movement between rooms. There is also a secondary boxing of dry wall filled with rockwool at the top of the wall to the ceiling to give additional isolation. Will post a picture tomorrow that will make more sense.

These pics hopefully show how I'm trying to reduce flanking. The open ceiling space between live and control room has thick T50 barrier matting suspended from the joists. There is then 2xlayers of 12mm drywall. There is then a box made of 12mm drywall, filled with rockwool and with sunken lights built in. Therefore sound hits the box, is absorbed a bit in the rockwool, hits the double layer plaster and is absorbed a bit more in the T50. I'm going to add mass loaded vinyl to the tops of the walls and ceiling in an effort to prevent sound escaping via the roof. Any other ideas for keeping drum noise under control?