John Sayers' Recording Studio Design Forum Archive

Here are my thoughts: this is for live/dead room only at this point, other rooms to follow after I get these down

Orange (live room):these have concrete on the other side, so I will put in insulation, in that concrete side of the wall, then build the angles out, fill those walls with insulation (so there is an airgap between the 2) then do slots in varying widths (should this be random or build up in width of
gaps?)

Blue (Live room): same as orange, only backed with MDF.

Brown(dead room): use hangers and 703 covered by drywall of varying thickness.

Green(dead room): Walls backed by MDF, hanging 703, and varying thickness drywall on the angles walls.

k...what do you think?

Keith, either Live or Dead room, with all that STIFF concrete you're going to want as much bass trapping as you can get. For ALL those angled walls in your tracking rooms I'd put up 2x4 studs on 24" centers, then put your 703 hangers behind them and panel them with alternating 1/8", 3/16" and 1/4" plywood panels 24" wide, with 3/8" plywood panels near the deepest parts. You can use construction adhesive and glue a strip of insulation to the insides of the panels that's about 6" wide, so that the fluffy part touches the panel and runs lengthwise. This will damp the panel and widen the response, making it more even.

The 3/8" panels in front of 18-20" air space will resonate near the low E on a bass guitar, so will take some of the boom out of that note. The rest of the thicknesses, placed over narrower gaps as the panel thickness decreases, will do the same for upper bass frequencies. Gluing soft insulation strips on the panels will widen the resonance and smooth out the response, although lessening the total absorption.

For your Dead end, you can just mount 1" 703 about 1" in front of the resonator panels, and you'll still get the bass trap effect but with a deader upper mid and high end. If you make these portable, you can kind of "tune" the room to your tastes easier.

I'll stop now and let you figure out your next round of questions, while I figure out the next round of answers Steve

so the mdf on the side that backs the control room and vocal room is a good idea?

also, I want to use plywood for the facing of the live room and the slats for the dead room? Do you have any pictures of this (I am very visual)
lastly, should I carpet the dead area, and leave wood exposed in the live?
I noticed you didn't mention rockwool at all...do I not need it in this room?

Ok, next round is the vocal booth...I am lost here, some people say wood for the lower panels, not for the above, other people are saying kill the whole room...what is my plan here?

thanks as always!

also, strange idea...but what about using a windshield from a car for the control room window...its curved! eh...just a thought.

dammit, sorry to keep posting...but for my angles...how should I calculate it...eg, for every foot in length, come half foot out, or something like that. Please specify by color the angles I should be going for.

Keith, I'll try to answer all your questions as soon as I can, but try to realize something - we have, so far, 514 members signed up on this site - there are THREE of us moderating all the forums, so it gets really difficult to repeatedly answer questions that are already answered in the many resources that are already available here. You've been referred to them already, and claim to have read them - but just reading things through once doesn't give it a chance to "sink in" always. Case in point - you talk about using "slats" in your "dead end" - yet, here is a quote from one of the pages on absorbers at the SAE site -

"If we vary the depth from the wall, slat width, slot width (and the slat depth) we can create a wall that is a broadband low-mid frequency absorber. The beautiful thing about these absorbers is that they still reflect high frequencies, in fact they will diffuse them which is even better." - The part, "still reflect high frequencies", means that this will NOT make a room sound "dead", but actually keep it "live" sounding.

I'm not trying to irritate you here, just make a point - in a lot of cases, the answers to everyone's questions is already here in print if you look around a bit - sure, I know most of the answers already, as do John and Barefoot - but we're outnumbered here, and if we try to re-write every bit of information here each time someone has a question, we would never eat, sleep, or make a living.

I'm doing what I can to answer all questions as thoroughly as possible, because I am WELL aware of the difficulty of getting all the pertinent information together in one spot - still, it would help a lot if you could take advantage of what has already been said in order to better understand the principles of sound control and acoustic performance.

The more of these existing resources you study, the less you'll need specific one-on-one help to figure out your particular needs.

Please don't take any of this as a personal attack, because it's NOT intended that way. I just need everyone to understand my limitations of time and energy, and to help themselves where possible.

Some of the more helpful threads in this forum -

http://johnlsayers.com/phpBB2/viewtopic.php?t=634

http://johnlsayers.com/phpBB2/viewtopic.php?t=775

http://johnlsayers.com/phpBB2/viewtopic.php?t=598

http://johnlsayers.com/phpBB2/viewtopic.php?t=841

http://johnlsayers.com/phpBB2/viewtopic.php?t=728

If you will take the time to read these threads, I've laid out most of the rules and reasons for sound proofing in them. As far as acoustic treatment goes, I'll see what I can do in the next day or two to get ALL your questions answered -

Again, I'm not trying to avoid anything but I don't have the time or energy to repeat myself over and over either - the more you can learn from what's already here, the closer I can get to sleeping at least 4 hours a night. Thanks for understanding... Steve

sorry, my confusion stemmed from the term resonater panel, when discussing the dead room, when I read

http://www.johnlsayers.com/HR/index1.htm

it says: corner slot resonator for low-mid absorption. It consists of a MDF box with varying slats on the front installed with varying gaps. The variables are the depth from the wall, the width of the slats and the width of the gaps between the slats. The box created must be completely sealed to be airtight. The only access to the outer air is via the gaps between the slats

So, I thought that section of the room needed slats too. Unfortunalty, now I am all screwed up...sorry to upset you, that was not my intention.

Not to worry, my bad - sometimes I just get too much at once and don't want to short anyone. Still, not a total loss - here's what I got for you last night, things were slow enough to get some doodle-time -

Keith, I got a little time to work on your questions last night, and realized that there may be several changes that would work better for you - first, though, I need to know just how far along your construction is - how much of what’s on your drawing actually exists, and which parts are yet to be built?

Refresh my memory - what is the solid gray section inside your vocal booth?

For one thing, in your tracking rooms there is no need for everything to be symmetrical - if leaving out the angled construction on one side will leave you with more usable floor space, there’s no real reason not to do that. With your solid concrete outer walls, though, you WILL need lots of bass trapping of one kind or another.

You also still have (besides the ceiling and floor) another pair of parallel walls at the far ends of the live and dead tracking area.

I ran the modal response for your tracking area, attached is a plot of that. You will need to build absorbers for three different frequencies to tame the three pairs of modes that are too close in frequency to each other - These center frequencies are at 48, 149, and 298 hZ.

48 hZ is too low for practical Helmholz traps (slat resonators) without using excessive depth, so it would probably work better to build panel traps centered on 48 hZ, then tailor your slat resonators for 149 and 298 hZ. The 48 hZ panel traps should be placed at either or both ends of the tracking area, since that mode is a function of the width and length of the room the panel traps should be placed at all four corners of the room.

3/8” plywood over a 12” air cavity will give you the 48 hZ center frequency you need for the panel traps- these, being low frequency, should have all but the front panel built from heavy MDF - ¾” is fair, 1” is better. I would build four of these, 2 feet wide and at least 6 feet tall, sealing everything - you can use standard 6” house insulation inside, make sure the insulation doesn’t touch the front panel but is within 1-2” from it. You can “trap” the insulation by using chicken wire or other lightweight “hardware cloth” and a staple gun and fastening the wire mesh to the sides of the box all around. Thin wood lath or cleats over the wire with small screws where the wire lays flat against the side walls will make things stay put. This layer should hold the insulation at least 1” away from the inside of the front resonator panel of 3/8” plywood. All joints, including the front panel, should be caulked with acoustic sealant. All construction should be glue and screw. When finished, these traps can go in all four corners of your tracking area, facing each other, and against the walls. These are pressure activated traps so they need to be against the walls, not ¼ wavelength away.

At an average depth from the wall of 18”, a slat resonator with 1/10” slots between 5.5” x .75” slats, will have a center frequency of 146 hZ; with an actual depth of 12” to 24”, this would give a fairly broadband absorption centered at the 150 hZ frequency that needs treating. These should be the topmost section of your top orange section and the bottom-most section of your bottom brown section. I've numbered these #1 and #4 in my markup of your plan. For the dead end’s brown section, if slots make it too bright you can mount 1” 703 in front of (not touching) the slats with no ill effects.

Building this exact same slat resonator in front of an average cavity depth of 6”, but with the 5.5” x .75” slats spaced at 7/32”, will yield a center frequency of 300 hZ. That should be the other section of your upper orange and lower brown angles (sections 2 and 3), running from 0 to 12” deep. This 300 hZ mode coincidence, since it’s caused by the 4th harmonic of room height and the 6th harmonic of width, shouldn’t be nearly as strong as the others - however, that’s also the prime resonant frequency of typical kick drums, so having a trap centered on that frequency isn’t a bad idea even if it’s NOT one of the modal problems of the room.

For a good start on the basics of building these, click on the John Sayers Productions logo at the top right of this page, then click on “wall units” - You’d be building a modified version of the “Corner Unit”, or actually more like the “Wall unit” - actual spacing of the elements are spelled out in the two preceding paragraphs. These units also need to be sealed, except where the air goes through between the slats and through the cloth. They can be partially filled with any leftover insulation, either 703 or spun glass or rockwool. Try to keep the insulation spread out over the entire inside of the box, and fairly close to the front slats. If you have it, sheets of 703 will work well here.

As far as wall angles go, if you’re over 12 degrees total between two walls you’re fine. 1 foot in 10 gives about 6 degrees, so the 2 feet in 6 I drew for your traps will be plenty. The other two broadband absorbers (not 1, 2, 3, or 4) can stick out from the wall by 18-24” and be fine. This isn’t critical in the tracking area, symmetry is only required at the mix position.

Don’t use a car windshield - more problems than it’s worth.

2.5 pcf to 3 pcf rockwool or 703 should be used in all walls not otherwise specified, such as traps/absorbers.

I would only use MDF on free-standing units or for dividers between slat absorber sections - it’s too expensive for walls, and gypsum works as well for about half the price.

I would NOT carpet ANY part of the studio as a permanent thing - if it’s too live, you can always lay down an area rug. More choices that way.

On the vocal booth, I redrew part of it - with the new angles, you will probably want hard floor, 2-3” 703 ceiling, and 703 on at least one wall (probably opposite the slat absorber I added.) Don’t make it too dead, you can always do that later if it’s too live.

I think I covered just about everything you brought up so far - See what you think about the changes I made to your drawing… Steve

And my markup of your plan -

Knight, that is beyond amazing...I am dumbfounded. Thank you for taking that much time on that!

As to the construction question:

the studio room (live & dead) has been created as have the outer walls to said room. The floor was not floated (despite my protests) my thought right now is to lay down the tri-ply gaf and put another layer of wood on top (maybe mdf) to cut down on the boom. The floor is however filled with insulation.

The other rooms WILL be floated.

I thought I was in a big hurry last night because I always think things can be done faster than they can be, I actually thought the entire studio room would be framed last night...I have NO concept of time. I do however realize you put a lot of it into what you just did for me, and you have no idea how much I appreciate that...did you get ANY sleep last night?

The gray area in the vocal booth is concrete...we are in the basement of a car repair garage which is why EVERYTHING except the east wall is concrete. even the ceiling is concrete, which I am sure will present its own problems.

I am going to disect your post now...again thank you.

Unless you're getting a lot of rumble and traffic noise down there, I wouldn't worry about floating the studio floor especially if the other rooms will be floated. The sound you get is the main thing.

I know it's hard to wait for something when you can "already taste it", but try to keep in mind that rushing this type of construction usually ends up being a waste of time, materials and energy. Take it slow and careful, always ask questions BEFORE you do something instead of after, and you'll like the result a LOT more. I can point you to posts from people who've tried both ways, if you need confirmation -

And no, I didn't get any sleep last night. I was "saving the world from explosions and chemical spills", at my "DDJ" (That's Dreaded Day Job, even though it's sometimes at night) - Fortunately for both of us, it was a relatively quiet night and left me with a few hours to fill - I did, however, get some sleep today so I'm good for another 24...

And you're welcome - I probably should have been a teacher, except this is better because here, people actually WANT to learn so it's more fulfilling... Steve

I am going to start with the north/south walls, I have built a room with in a room, and so the wall sticks out some...so, my assumption is...I put up insulation (R-13 or similar is what I was going to use on these walls) into the studs (so there will be an airgap between the insulation and the old wall), then drywall over that insulation (one sheet since I don't have to worry about sound escaping), then hang the Helmhotz traps on those walls facing each other.

Is this correct?

You lost me - is the top of your drawing North? Because the only traps I show facing each other are the panel bass traps, not the Helmholz (AKA Slat absorbers) Steve

I really keep screwing up the verbage and I know that has led to confusion...sorry for that. I did mean to say the bass traps.

No prob, remember you're learning a new language here. Doesn't happen overnight, I know - it took me years, you're doing great... Steve