but the reality check is good. Better now than later, right?
Not really, just time & money and trying to avoid dealing with the ceiling.
IT would be nice if you could avoid dealing with the ceiling, but going back to the fish tank analogy, that's like saying you want to avoid dealing with the floor... just sort of leave it out, or maybe use cardboard...
That was my initial thought but the more I planned and looked at materials (when did building materials get so expensive?!?) the more I gravitated toward the one-big-well-treated-room that I can use for music making, tracking, etc. A control room would be great, ...
Before finalizing that decision, you should think about what you actually need to do in there. If it includes a largish percentage of tracking, mixing and mastering, then a control room might be worthwhile. Because: In order to track, mix and master well, you need to be listening in an acoustically neutral environment. But a live room / rehearsal room is certainly not neutral! You don't want it to be neutral! It needs to have its own character, "vibe", and "sound" that makes it pleasant to play in. But "pleasant to play in" is not what you need when you are mixing... so you have two conflicting requirements here. Whichever one has the greatest priority is the one that's going to win out, of course, but then do realize that the other priority will suffer. A room that sounds wonderful, warm, bright, airy, harmonic, etc. for playing in, will be a terrible room to mix in, and your mixes will suffer, since you will subconsciously try to "correct" the sound while you are mixing... it will sound great in that room, but lousy everywhere else you play it, because nowhere else has the same acoustics as your room. On the other hand, if you mix such that it sounds great in a neutral room, then it will also sound great everywhere else.
So, if tracking/mixing/mastering is important to you, and also rehearsal, jamming, etc., then maybe having a neutral control room as well as your main room, would be a good option.
Pretty sure I heard him say "sister" and he was definitely talking about horizontal beams spanning the angly bits to hold the walls in.
Here's a case in point, from a studio I did a few years back for a customer in California. He started out with a garage that had low joists across the wall tops, that greatly limited the maximum height. Along with the structural engineer, we designed modifications to the trusses, so we could get the ceiling a couple of feet higher, like this:
BEFORE:
OWCAUS--ORIGINAL-roof-inside-SML-ENH.jpg
AFTER:
OWCAUS--FINAL-roof-inside-SML-ENH.JPG
Those are raised tie or "collar tie" trusses, after the modification, and you can see how the old rafters are "sistered" with new ones. You can also see the cross.bracing between the trusses. We then attached drywall to the underside of those modified trusses, and together with the existing wall, that became the "shell" or "envelope" or "outer-leaf" of the isolation system. We then built the inner-leaf within that shell, as framing for the walls and ceiling, with drywall on just one side of that.
That's what you could do too.
I need to build walls-within-walls
Right. Your existing walls will be your outer-leaf, and you need to complete that shell with a new "middle-leaf" ceiling (as in the photos above), then you can build your "inner-room" as 4 walls plus a new ceiling. The "inner-room" cannot touch the existing structure anywhere: not even one single nail. It's a totally self-supporting, isolated structure.
I need to build a middle leaf for the ceiling, and then a second ceiling inside of that
Right, but thick of that final ceiling as being part of the inner-leaf, as a single integral structure.
I need to either reengineer trusses to get more headroom or live with a 7' ceiling
Well, the acoustic ceiling can be higher than 7', pehaps 7'10" or so, but the actual visible ceiling would likely be around 7'-something and a bit. Which is not good if you want to track drums....
This is much bigger job than I was hoping
Welcome to the world of studio building!
(Get used to that phrase... you'll be saying it a lot. Also get used to the companion phrase that goes with it: "This is much more expensive than I was hoping.")
~120 db at the kit
~85 db outside, a few feet away from the wall
Sounds about right. So you are getting around 35 dB of isolation at present, which is typical of a house wall. Slightly better than normal, actually which is good.
So now you have answered one of the two key questions: "How loud am I?". Now you need to answer the other one: "How quiet do I need to be?". When you have those two answers, you subtract the small number from the big number, and the result is how much isolation you need!
So, to fined out "How quiet do I need to be?", visit your local municipal offices or website, and get a copy of the noise regulations. That will spell it out for you, clearly.
Once you know that number ("How much isolation do I need?"), you can start planning what construction techniques and materials you will need to get there.
• If I'm building MSM walls, can I skip acoustic caulking the seams on the outer wall and roof?
Nope!
No short-cuts. There are two major things you need to know about getting good isolation. 1) Mass. 2) Hermetic seals. If you have lots of mass on each leaf, and perfect hermetic seals on each leaf, then you will probably have good isolation. If you don't have much mass on both leaves, or don't have good seals, then you definitely won't get mush isolation.
Here's the thing:
loss-crack-reduction-effect-of-gaps-on-TL-GOOD!!!!.jpg
I wish I had a more clear copy of that graph, but you can almost read it... What it shows is how much isolation you will end up with, if you have tiny air gaps and cracks in your walls.
So let's assume that you wanted 50 dB of isolation. So you read across the bottom axis, and the final number on there ism indeed, "50": If you then go up that vertical line until you reach the curve that shows how much gap you have in your wall, you'll feel your wallet sink to the floor, along with our jaw.... The fourth curve from the top, for example, is labeled "0.1%", and since it hits your vertical line at the horizontal level of "30", that means that if you have just 1 tenth of one percent of your entire wall area as "gaps" or "cracks", then your total isolation would be 30, which is 5 points LESS than what you are getting now....
Or if you think you can do a much better job of sealing, five times better, then you'd go up to the next curve, and learn that a wall designed for 50 dB isolation that has just 0.05% open area (gaps), will achieve about 33 dB of isolation. And if your wall is sealed another five times better, having just 0.01% open area, then you still only get 40 dB of isolation out of a wall that should give you 50.
So yeah, sealing those cracks is important. Critically important. If you see an obvious crack, seal the hell out of it. If you aren't sure if it is a crack or not, then seal it anyway. And if you are totally certain that what you are seeing is NOT a crack, well, seal that too, just in case.
Did I mention that sealing is important?
(Oh, and don't forget to seal!)
- Stuart -
