Commercial Space Buildout

Hey guys, I'm hoping to get some guidance towards turning a 2 room commercial space I rented out into a decent sounding project studio. The biggest issue is to eliminate sound leaking in from the rehearsal spaces upstairs in the building it's connected to. As you can see in the picture, there's a 3 floor section connecting to a 1 floor section. I'm in the 1 floor section, however if you look at the blueprint (sorry for the mess), I share a concrete wall with the stairway of that building.. the stairway leading up to the 3rd floor where the practice rooms are located. The machine shop is not an issue since they don't work in the afternoons - which happens to be the only time during the work week that bands are allowed to rehearse - hence my problem.. I have a day job and I'll be getting to the studio at the same time the band rehearsals would be going on. I'm hearing the low to mid frequencies from the drums, bass and guitar more than anything. There's a 12-15 dB spike in those frequencies- which I read through a Real Time Analyzer app on my iPhone called JL Audio. The readings of the band playing and not playing are pictured. They were read from the iPhone's internal mic, positioned in the middle of the room facing the back wall. My budget is roughly $1000 for both rooms at this point. I'm not sure if that's gonna be enough, but in addition I purchased a lot of leftover material from contractors off of Craigslist over the last 2-3 months (by far the best way to save loads of money on unused construction material) So far I have: • 860 square feet of 5/8" Type "X" drywall (National Gypsum brand) • 2 boxes of Green Glue • 7 tubes of Silen-Seal acoustical sealant • (6) 3 packs of Roxul 2' x 4' x 5" Rockboard 40 About the rooms: (Room dimensions are from existing drywall to drywall) 19'6"(L) x 14'4"(W) x 10'(H) - This room is to be used for mixing, mastering, and recording a variety of genres in stereo and possibly surround sound later on. In addition I'd like to be able to get this place decent enough to hear an accurate low end for mixing since I plan on later getting a sub. As for what kind of monitoring system I'm looking to use in the control rm/project studio, I'm still in the market but I imagine I'll have to start out with the best possible option for a pair that runs around $500-$600. I'm hoping to get an accurate low end reading in this space since I'll be eventually looking for another near-mid field monitoring system including a subwoofer (preferably one reaching down to 20 Hz) when I can afford it. 13'2"(L) x 11'4"(W) x 10'(H) - Vocal/Instrument sound isolation booth without a door or window for now. I'll just go with the camera/monitor solution for now considering my budget. More about the space: - The floors are built of 6" concrete floors and the top covering is vinyl, which I will be replacing. - The ceiling has steel(?) trusses extending approximately 18" down and spaced 22" apart (pictured) - The back wall is load bearing, and made of a cinderblock/stud/drywall assembly which joins the two sections of the building - This load bearing wall is also fastened to the main circuit breaker box for the whole 1 level part of the building. In addition, I found there are holes drilled halfway into the cinderblocks, not sure why.. Also, I'm assuming I haven't heard all the bands that practice there since I've barely spent time in the place, so it's also worth bringing up that the the low to mid, and possibly higher frequencies can fluctuate based on: - Which band is practicing - Their room's proximity to mine - How loud they play - If they are bumping massive subs, ect. I have done the recommended research, so I do understand the fundamentals of architectural acoustics, however, I don't know the most optimal solution for this project here. Just thinking about all the possibilities gives me a migraine... I'm hoping for a visual explanation or blueprint of what you generous experts would consider "optimal" under these circumstances. As far as specific questions that come to mind: - Would floating floors be necessary? (since the concrete is structurally connected to the rehearsal rooms.) - Will I have to treat the steel trusses a certain way or can I just hang rockwool from them. I'm mainly worried about if there are going to be a problems as far as them resonating. Anyway, I sincerely appreciate the time and effort anyone can contribute to this. Also, a big thanks to Mr. Sayers and all the contributors here. This forum is the most helpful resource I've found for the DIY guys like myself just starting out. -Joe from Palatine, IL

Hi Joe, and welcome! :) Your post is all messed up for some reason, and the photos are all out of place, at the bottom, so it's a bit hard to follow what each paragraph refers to! Anyway, a few comments: 1). don't trust RTA apps on smart phones. The mics and internal circuitry on smart phones are nowhere near useful for even half-heartedly serious audio work, and certainly not for acoustic measurement. The app might be fine, but there's no way it can compensate for the major, horrendous deficiencies of the phone itself. There is one company that sells a good measurement mic and app that works well, but in total it costs way more than a professional meter, so it's not really worth doing that way. So at best, the readings you show can give you a sense that there is a difference between "band playing" and "band not playing", but the RTA graphs are certainly not showing anything like reality.

The readings of the band playing and not playing are pictured. They were read from the iPhone's internal mic, positioned in the middle of the room facing the back wall.

The reason why you are not seeing/hearing the lows is probably because you stood in the middle of the room, which is the where a whole bunch of modal nulls are located! I bet if you put your head (and the meter) in one of the room corners, you'll find a whole lot different picture going on, with more activity in the lows. (Well, you'll probably hear the difference but not see much of it on your phone app, as they simply don't work well down that low). In reality, you should try listening/measuring in the same location where your chair will be, once the room is finished.

I'm hearing the low to mid frequencies from the drums, bass and guitar more than anything. There's a 12-15 dB spike in those frequencies- which I read through a Real Time Analyzer app on my iPhone

That's what you are hearing, I'm sure, but not what the graphs are showing. the kick drum normally has a fundamental around 80 Hz or so, and toms are in the range above that. Bass guitar goes down to about 35 Hz, and puts out lots of energy in the range 50 to 100 Hz. That just isn't showing on the graphs at all. In fact, there's a dip in that range, not a peak. How was that meter app set up? Was it set for A-weighting, or C-weighting, and what sort integration time? Without knowing that, it's impossible to say what that graph is actually showing. 2). It seems like you have several potential problems with the room: First, as you pointed out, is the flanking in the building structure. The impact noise is getting into the floor, walls and ceiling, so that's an issue. Next is the stair well: that's probably a great path for sound from "them" to "you". Third is that electrical panel: there are doubtless a whole bunch of conduits running from that box to "their" rooms, and doubtless transmitting sound. There might also be entire shafts in there, which would be eve worse. Forth is seals. The existing doors and windows probably don't have any. Fifth is HVAC. You didn't mention it but I guess the building must have an HVAC system, and if so then you have another major flanking path, through that. 3) To deal with the above, you are going to have to go with the usual two-leaf fully-decoupled MSM "room-in-a-room" concept, with plenty of mass on the new walls and ceiling. You can take the electrical panel out of the equation by build a wall in front of it, with a door for access if needed. 4) Your budget seems very, very low. To get an idea of what this will actually cost you, realistically, call some building contractors in your area and ask what their basic rate per square foot is for building a home theater in an unfinished basement. That's roughly what it will cost, less a chunk for labor if you are doing the work yourself. Right now you say you have a budget of about US$ 1000, and you have a total of about 400 square feet. That works out to just US$ 2.50 per square foot. Compare that against the rate the contractors quote you. My guess is that they'll be giving you numbers much closer to US$ 100 per square foot. That's not to say that you can't do anything with your room! it just means that you can't do what is really needed to do, to fully isolate and treat those rooms properly. So you won't be able to get decent isolation from the bands rehearsing in the other rooms. You say you already have a whole bunch of materials, which is an excellent start, so that certainly helps. But the question is this: is what you can do with your budget good enough? How much isolation do you actually need?

This room is to be used for mixing, mastering, and recording a variety of genres in stereo and possibly surround sound later on.

If you are going to do surround, then the room should be designed for that from the start, even if you'll only be doing stereo or 2.1 initially. Modifying the room later is going to cost a huge amount, so much better to do it right now.

In addition I'd like to be able to get this place decent enough to hear an accurate low end for mixing since I plan on later getting a sub

If you want accuracy in the low end, then flush-mount ("soffit mount") your mains. That's the best single thing you can do to tighten your bass.

- The floors are built of 6" concrete floors and the top covering is vinyl, which I will be replacing.

you don't have enough money to replace it. Even low-cost laminate flooring is going to cost you much more than US$ 2.50 per square foot, which is your entire budget. Fortunately, vinyl is a good surface, acoustically, so you don't need to replace it. Leave it there for now, and if you have more money down the line, then you can replace it. Another alternative would be to just take it out and leave the bare concrete, which is also a great surface for a studio floor, acoustically. (It might not be nice aesthetically, though.)

- This load bearing wall is also fastened to the main circuit breaker box for the whole 1 level part of the building. In addition, I found there are holes drilled halfway into the cinderblocks, not sure why..

Like I said above, the easy way around that is to build a new wall across in front of it, as part of your isolation system. You might need to put a door in that wall for access to the panel, but it sure beats trying to isolate the panel and entire electrical system!

- Would floating floors be necessary? (since the concrete is structurally connected to the rehearsal rooms.)

Once again, you don't have enough budget to do floating floors. That takes many thousands of dollars to do properly. Concrete isn't cheap, and neither are the springs. One option might be to just do a decoupled floor, along the same lines as a drum riser, which is much cheaper, but you don't have the budget to do that either. So I'd say that your only options for flooring are to leave the vinyl as it is, or to take it off and leave the bare concrete. Both are good options, acoustically.

- Will I have to treat the steel trusses a certain way or can I just hang rockwool from them. I'm mainly worried about if there are going to be a problems as far as them resonating.

Neither. Hanging rockwool is going to do nothing at all to isolate the room. Your only option for isolation is to build a room-in-a-room, which would take the existing roof out of the equation: I'd suggest that maybe a three-leaf ceiling would be a real option in your case, where the existing roof would be the third leaf. In that case, you probably don't need to do anything up there, except to build the two new leaves. Anyway, I'd suggest that you should try to beg, borrow or buy a real sound level meter, and conduct some proper tests in that space with the meter set to C-weighting and slow response, to get an idea of what is really going on. Then based on that, figure out how much isolation you need. That will lead you to the right building materials and techniques for attaining that level of isolation (and you already seem to have a bunch of the right things), then you can design the actual "room-in-a-room" structure. It's a decent sized space, but the real issue here seems to be budget, not acoustics. - Stuart -