The school where I teach wants to use a music classroom as a rehearsal space for the 6-8th grade band next year. It's about 21' x 26' with 9.5' standard classic white drop down ceilings and carpeted cement floor. Our band director says (and I agree) that it's unhealthy for children to rehearse in this space. A horn section with 4 or 5 trumpets will be deafening.
Until the school is able to build an actual rehearsal room, we are tasked with making the space work, so I have a few questions. Will the type of treatment I have in my home recording studio be of any help? I always think of it in terms of taming specific frequencies and getting rid of reflections (reverb), but will it actually reduce sound pressure levels?
What about raising the ceiling? There's a good 2 feet of space above the acoustical tiles. There would leave a lot of exposed ductwork - but might the extra volume help? For that matter there are two closets that could be demoed that would increase the floor area by about 30 or 40 feet2, for maybe 350 cubic feet.
Thoughts? If we bring in an acoustical architect, what kind of solutions might we expect?
Post by ExponentialAudio on May 3, 2017 13:06:03 GMT -6
Treating a room that size will be expensive and I'm not really sure you're going to get the levels down a whole lot. Room treatment typically focuses on diffusion, minor absorption and control of low frequencies. It might make things seem quieter since the room won't be as harsh. But I don't know that you'll actually push the levels down a whole lot. For the midrange (which is where most bands live) to get choked down is probably going to take some very thick panels. The sound energy is essentially baffled and converted to heat (miniscule amounts), so it needs to go through a lot of stuff.
OSHA recommends an average level of no greater than 85dBA for an 8-hour period. When I go on dub stages operating at those levels it just about kills me. I'd personally knock that recommendation down 5-6 dB. If you can take your trusty Radio Shack level meter into the room in question with the band playing, then you'll have an idea of what you're going to have to do. You can start out talking to a company like ATS (maker of nice traps and panels) to get an idea of what you can do before you engage a real expert.
I think that your concern is well-placed. We've already had a couple of generations of hearing damage as the result of ignorance of loud music. In the short run, you might look into buying a crate of whisper mutes (only half-joking).
I would say, aesthetics of the room's sound aside, dampening the high end will make the room much less fatiguing. If the drama class has any large backdrops lying around, I'd hang one opposite the wall they're playing. Horns are very directional and rely heavily on reflections for their dispersion, so taming the first reflection will make a big difference. The next issue would be to tackle the specific modal rings in the room, as they'll be loud and they'll also be a distraction for the band.
RE: Ceiling. Leave well alone unless the ducts rattle - again, additional noise. The school probably has some decent HVAC so it shouldn't, but it's a consideration.
Rooms with high absorption will always be quieter than their more reflective equivalent, it's just balancing it to the point where you can still play as a band - it's harder without some detailed reflections coming back.