advice for an attic-style room

hello all. via google and gearslutz, this seems to be the place to ask these questions so here goes! having recently bought a place finally, i've started stripping one of the bedrooms to make into a little studio just for making & mixing. i threw together a quick sketchup of my basic plan: mostly i want to see if i'm headed down a very bad path with anything i'm trying to accomplish. right now the room is almost down to bare studs, as the previous owners did not exactly leave some of it in the best of shape so i figured the best course was to just start fresh. (there was an old window in the middle of the outside wall that they just slapped wood panelling over... good times) anyway, i'm terrible with sketchup, so some extra info: the walls in the room pictured will probably just be 1/2" drywall, a 1" gap, and another layer of drywall. unless it's the wrong thing to do, if i can afford it i'd like to cover the whole room in 1" 703 (covered with cloth)... is this a good or bad idea? any help or advice is awesome! -andrew

whether i'm not getting replies because i left a few things out or not, i don't know... my budget is probably $2K USD at most... it's a bit flexible but given i have some panels already i've at least got a start this is a mixing and listening space, not a record-drums-loud space so i'm not too worried about high DBs here. every now and then i'll turn up my mons to hear how something translates loud but most of the time i mix between 80-90db. i'm next to a road so quieting that down a bit would be a nice side effect of "stop sound getting out" treatment, but isn't that important as i won't really have open mics in this space. i really only record guitars via my own cabinet isolation boxes & software so that doesn't matter as much. i think that's all to fill in. i have two months off from touring so now is the time to get it going. i truly hope i'm not getting ignored because i missed some inane fact :( (i'm almost done clearing it out completely and planning starts)

Hi Andrew, and Welcome! :) Sorry about the delay in replying: There's a lot going on around here lately, and I seem to have a long line of threads every day that I need to reply to! I wish I had more hours in the day... :)

so i figured the best course was to just start fresh.

That's probably a very smart move: By taking it all down to bare studs, you can more clearly see what you are dealing with. It would help if you could take some photos of what you have, and post them here so we can also understand it better.

the walls in the room pictured will probably just be 1/2" drywall, a 1" gap, and another layer of drywall. unless it's the wrong thing to do,

How much isolation ("soundproofing") do you need? That's the key to determining what materials and techniques you need. But in general, 1/2" drywall is too thin, to light, and too flexible to be good at isolating. 5/8" drywall is much better. Also, when you say there will be a gap between, 1" is not enough. The gap between the outer drywall and inner drywall needs to be at least 4". If not, then the resonant frequency of the wall will be too high, and it won't isolate low frequencies well. Also, that gap must be air, only air, and nothing else but air (or rather, air with insulation in it). In other words, there can be no hard, mechanical connects between the inner and outer drywall. For moderate isolation, you need either proper Resilient Channel, or RSIC clips plus hat channel. For higher levels of isolation, you need separate stud frames for each.

if i can afford it i'd like to cover the whole room in 1" 703 (covered with cloth)... is this a good or bad idea?

You can do that, yes: It is possible, but it will make the room overly "dead", and you will need other types of treatment to deal with that. In fact, there is a type of construction called "inside out" walls, which you could use. But your basic treatment plan looks reasonable, provided that those mineral wool panels are thick enough, the correct density, and placed at the right locations. And you will need a lot more of them! You will also need lots of bass trapping in that room, and additional absorption in the rear ceiling and rear wall.

i truly hope i'm not getting ignored because i missed some inane fact

Not at all! You aren't even being ignored! Rather, it's just a problem of "moderator overload"... there aren't too many folks reply to threads right now, unfortunately (I wish more would join in!) and a lot of threads going on all the time.... - Stuart -

Also, when you say there will be a gap between, 1" is not enough. The gap between the outer drywall and inner drywall needs to be at least 4". If not, then the resonant frequency of the wall will be too high, and it won't isolate low frequencies well. Also, that gap must be air, only air, and nothing else but air (or rather, air with insulation in it). In other words, there can be no hard, mechanical connects between the inner and outer drywall. For moderate isolation, you need either proper Resilient Channel, or RSIC clips plus hat channel. For higher levels of isolation, you need separate stud frames for each

. i might scrap that idea then. it's not going to be overly loud, and my house stands separate from the neighbors so even without it i should be ok.

You can do that, yes: It is possible, but it will make the room overly "dead", and you will need other types of treatment to deal with that. In fact, there is a type of construction called "inside out" walls, which you could use. But your basic treatment plan looks reasonable, provided that those mineral wool panels are thick enough, the correct density, and placed at the right locations. And you will need a lot more of them!

i have quite a few as is, some rockwool and some rockboard. i figured on building more anyway but, those are things that i can at least add to the room after the walls are up and aren't as huge a priority as having walls at all :D

You will also need lots of bass trapping in that room, and additional absorption in the rear ceiling and rear wall.

i'll have PLENTY of leftovers from doing the walls and ceiling with mineral wool... using that and buying more i want to put superchunks in the front and back corners, and MAYBE a skyline 2D on the back wall, but i don't know how effective that will be vs just a bunch of thick panels

Not at all! You aren't even being ignored! Rather, it's just a problem of "moderator overload"... there aren't too many folks reply to threads right now, unfortunately (I wish more would join in!) and a lot of threads going on all the time....

i thought as much... but like i said i'm trying to make a personal deadline to get started and was hoping my plan was semi-sane :) thanks! -a

(also I'll take some pictures when I get home, though everything is a scrap heap mess still)

a few photos, still in the middle of cleanup... there's also a phone panorama thing here which features my lovely wall mount boom box =D fun fact: there was an old window still in the wall when i took the crappy wallboard off. lovely repair job, former owners...

lovely repair job, former owners...

:shock: 8) Yup! That's for sure! - Stuart -

ok, drywall up, time to paint and plan treatment. i'd post photos but i don't want to embarrass myself, so sketchup is going to be it. the other threads on this forum make me so depressed about my existence and that i even tried this at all. so: picture and sketchup attached. in the model, brown stuff is roxul Safe n Sound, blue stuff is existing rockboard panels. the chunks are two large and two small pieces from a single piece of safe n sound due to my not unlimited budget, so they can't really get any bigger. any help is entirely humbling. i feel like an idiot. -a

i'd post photos but i don't want to embarrass myself,

Don't be embarrassed! It's important to post photos, so we can take a look and see if there's anything you might have missed, and could be improved. Nobody cares what the drywall and framing LOOKS like, as long as it is built correctly and sealed correctly: The goal is not to win prizes for aesthetically beautiful architecture! The goal is to have a room that SOUNDS good. Sound waves are blind, and can't see how the room looks, to they really don't care about appearance! So just post the photos already! Nobody will laugh, I promise!

picture and sketchup attached. in the model, brown stuff is roxul Safe n Sound, blue stuff is existing rockboard panels. the chunks are two large and two small pieces from a single piece of safe n sound due to my not unlimited budget, so they can't really get any bigger.

The plan looks pretty good, actually. The reverse-sloping walls are an interesting concept: I haven't see that done before, but I'm sitting here thinking: "Why the hell not?" I can't see any reason why that wouldn't work, especially considering your cloud design and other treatment. I think it will be fine. I'm looking forward to seeing the REW tests, and I'm betting that your modal problems will be minimal. Is there any treatment in the room yet? If not, it would be a good opportunity to do a baseline REW test, and see how the room behaves empty, then put the treatment in bit by bit, and do tests after each set to see how it has affected the behavior. That would be very instructive. - Stuart -