Goals:
Most of my life, as a drummer, I've always had to make compromises - e-drums, shared rehearsal spaces, never having truly private practice space, to play or sing - but now, I'd like to do whatever is needed to turn this room into a space where I can play anytime, and have a few people join me. The primary goal is soundproofing- but if I can make this space sound great too while I'm at it, by, say, avoiding terrible ratios, keeping walls not parallel, appropriate acoustic treatment, that would be great, and I'd record in there too.
The unit is on the first floor (2nd floor for those in the U.S.), of what used to be an old warehouse or factory in London. I want to soundproof one of the two rooms of the unit.
There is at least one world-class recording studio close by, and I don't expect to compete- but if I can offer recording of single instruments as a service, or voiceovers / podcasts, that would be nice.
You may notice there's no provision for a separate control room- I intend to do basic recording and mixing from the large room using headphones, but if it ever came down to serious mixing, I'd need to do this elsewhere, or if the small room ends up sounding great, move in there with some monitors during post production.
If you're wondering about the larger room's purpose, it is photography and some filming, and I'll aim to hire it out as much as I can. If I can improve the attenuation of that room's walls to the corridor and neighbouring units, to allow occasional filming of a small acoustic set there, that would be great- but that's definitely for a separate post!
Bottom line is, I would like to achieve as much isolation, for a rock drumkit and amplified instruments (guitars, keys), producing, say, 120db, as about £6,000 will get me. My DIY skills are middling - I've never even framed a wall - so while the romanticism of "building my studio with my own hands" is appealing, and I'd love to learn, I think it will make more sense to pay someone with more experience to build it right the first time, and quickly- This is especially true for any local contractors the members of this forum can recommend for the job. This isn't a project I can afford to chip away at at my leisure for years to come, but something I need to get built ASAP, because leasing this space is expensive.
So, I'd like to arrive at a final design with your help, and then will likely need to hire people to do most of the construction.
The surroundings:
Seen from above, the unit has a wall on the left edge to the neighbouring unit (A). To the right, there are the bathrooms (B), to the top there is a corridor (C). Walls to A, B and C are rather thin and badly sealed, not quite flush to the ceiling. The bottom wall is an exterior wall, 350mm brick. There are units on the floor below, which used to be, and may in future remain, recording or rehearsal spaces. Outside the building, there is another commercial building to the East, about 2 metres away, without windows. To the South there are flats, at least 6m away, but fortunately those walls are also windowless. The roof is a flat plywood and felt roof.
The room:
It measures about 5.6m by 4.35m, and 3.35m high. Currently, there are solid wood floorboards on a 250mm concrete slab, a wood panelled ceiling, plastered walls, and two sets of recently installed, double-glazed, PVC-framed windows, about 2.3m wide and 2m high. Three of the walls are exterior walls, and the other wall abuts the rest of my unit and the common bathrooms. One corner is concrete up to the level of the wood flooring.
My plan for the room:
- Remove existing floorboards, pour concrete to raise and level floor, and to add mass and provide a solid base. I had a structural engineer visit this week, who said he would tell me how much more weight the floor could take, and I'm waiting on that still. By my reckoning, adding, say 5cm of concrete to the floor of this room would add about 2.8 tons.
- Add two layers of soundbloc plasterboard directly to ceiling.
- Prepare active ventilation, making a silencer for intake and output as described here. I'm expecting holes will need to be made in the exterior walls next to the existing windows.
- Drill hole through wall for power / data / audio cables
- Build the frame of walls and ceiling of inner room, with wood studs, bolted to the concrete below, creating a 250mm air gap to existing walls, and making, say, 2.7m high frames.
- Install OSB as floor, with machined wood flooring on top.
- Make MDF boxes for power sockets, power for lights, ethernet, XLR snake, as done for the snake in this post.
- Add windows made of single, thick, slightly angled panes as described here, but of course only one side of the diagram, and without any connecting fibreboard since the existing windows would be the outer windows. If the windows, were, say 1.2m wide and 1.5m high, at 15mm thick, this site prices each pane at £576, and their calculator says each would weigh 67.5kg.
- Install heavy inner door with window (something like the doors used in this thread would be great, would love to hear any UK recommendations)
- Fill space between studs with rockwool or equivalent
- Attach two layers of green-glued 15mm Gyproc SoundBloc directly to the wood stud frame, so without resilient channel, while installing the MDF boxes.
- Install second heavy door with window at the entryway, next to the sink.
- Seal the walls and ceiling with acoustic caulk.
- Acoustic treatment with bass traps, diffusers etc.
Some questions:
- Anything wrong with my plans? I've probably forgotten something.
- Is the angle between opposite walls big enough to prevent resonances? So, are the walls far enough from being parallel to make a difference, or might I just as well make them parallel, and replicate the room's chamfer, or whatever you'd call that corner in the top left? There is about 3.5° difference between opposing walls.
- I'm not on the ground floor, so I worry about transmission to the floor below, or the floor slab conducting flanking sound beyond the inner room. Of COURSE I'd like to avoid floating the slab I'd pour- but can I really avoid flanking to neighbouring units, and the floor below, just by thickening the floor with extra concrete, and using risers for drums and amps? The recording manual speaks highly of floating floors, even just timber, the "don't use floating floors" post, of course, does not. If the consensus is that this particular room could benefit from this, I'd love to hear rough estimates of how much you think this would add to the bill, and how much additional attenuation this could achieve. This monstrous thread has some pretty clear instructions, for a timber floating floor, and while I'd feel confident with making the required calculations, again it's my DIY skills that will limit me, and I'd need a contractor to actually execute this.
- What's the smartest way to add HVAC to both the soundproofed room and the larger room? I'd need fresh air from outside, and the capacity to heat and cool. This matter of HVAC is probably the least clear to me. Assuming I can share it with the large room somehow, I can justify an increase in budget. Maybe the silencers could go on top of the ceiling of the inner room, to not lose floor space?
- Does the size of the air gap between the inner and outer walls (250mm) strike the right balance?
- I'd like to avoid having to build soffits for lighting, and would like to use some flat LED panels instead, along walls and/or ceiling- is it safe to screw this into the plasterboard (avoiding studs), or will this compromise the attenuation? What about heavier things like a little mixing desk, or even PA speakers for vocals / keys?
- If you agree replacing with wooden floor with concrete is a good idea, could I get away with removing only the boards, leaving the battens, and pouring the concrete over them?
- Should I also add a layer of plasterboard directly on top of all existing brick walls to add more mass for the outer leaf?
- Is the £6k budget realistic, or how much more do you think I'll need to build this?
Other concerns
Having said all this, the structural engineer who visited said I really shouldn't really try designing this myself, and should instead hire an acoustician and other specialists, because they'll do a survey, set goals for attenuation, and if they're not met after they've built it, then they'll be liable to fix it, whereas if I do this all myself and mess up, I'd be stuck. His ballpark estimate for the consulting work and design for this room, so without building anything, was £5,000, using people he works with.
My concern, after reading plenty of horror stories, is the risk of hiring people who don't really know what they're doing, and create some awful resonant cavities, or don't strictly follow the mass-air-mass principle of soundproofing, or don't appreciate just how much mass it will take to counter a loud drum kit.
Considering my situation, do you think I'll get the best result for the money by co-designing it here with you, and hiring people to build it under my supervision, or does it make more sense to hand this whole project over to a local firm that does the whole thing?
Thank you for taking the time to read all of this.
) will be even more expensive. i prefer forced air system since you can do all the functions in one system whereas a split AC/heat pump plus ventilation, etc will (imho) be more cost and work.
and they're designed to be shallow so as to fit in ceilings... in this case, you might put it in the adjacent room near the ceiling to keep the noise away from the isolated space.