My first studio construction - appreciate your help

This thread is intended to go along with my design thread here.. My design I'm going to have a lot of questions (and hopefully answers for others in the future), but I'll just start with a few. John is proposing I splay my side-walls, no real surprise there, and I agree that its best. You can see in the other thread that the idea is to actually just splay one wall 12 degrees. This wall is part of the leaf system, not just for acoustics. So I was going to use anti-sway brackets to support/decouple the walls at the ceiling. The illustrations I've seen though are all for walls running parallel or perpendicular to the joists. Since these wall will be running diagonal, how will that work? While we're on the subject, do I have to make these, or are they sold somewhere? Ok, a couple of other quick questions. I'm going to be adding sheetrock on the ceiling to subfloor above between the joists to add mass to the floor above before I put in the ceiling. Should I caulk any gaps between the sheetrock and joists or won't it make much difference? About acoustic caulk... Is it all the same or is some better than others? Any recommended sites for purchase? Well thats good enough for now. Thanks!

Home depot sell a cheap flexible caulk for about $1.50 a tube - I've used a ton of it and it's worked fine for me. Just make sure it remains flexible. For your walls - put your celining up first on the resillient channel and then have your walls push up against the drywall. If you put some of the foam playmat stuff on the top of the wall you can bash it up with a sledgehammer and then put a few bolts into the floor - the wall be decoupled from the ceiling joists and won't fall down.

Thanks for the tips Andrew, and more importantly just taking time to reply! I hadn't considered having the ceiling on first, didn't know if I could rely on the RC to hold the walls up. I know for sure that I can't anchor anything from the wall into the RC, but I suppose I could basically wedge the walls to the ceiling as you've described. The only thing I believe I'd have to be concerned with is the walls putting too much force against the RC and negating its "spring" action. Another question, Should I ride the wall frames on neoprene pucks? I'm in the basement, concrete floor, and not floating the floor in my control room. However I don't have to be concerned with trying to isolate myself from drum kits or amps in another room. I suppose if I'm not floating teh floor in my room, then I already have transmission going through the floor. The additional transmission from the walls to the floor could add too much. ?

When you build the wall frame measure the stud length exactly so it compresses the play mat stuff about half when the wall is pushed up. The play mat is sold at Home depot - its a bunch of jigsaw like fitting foam mats - about 25 bucks a pack - just cut it into strips and glue to the top of the frame. Tip - unless you floor is exactly level - measure the height of each stud & adjust For the bottom of the frame - I used foam insulation that is sold in rolls at Home depot - its normally used to insulate pipes - Soundproofing.org sell it for 5 times the price & call it supersound proofing tape.

Great, I got the picture now on the wall-ceiling connection. I think I have a picture of that play mat stuff in my head. I know what that pipe insulation is, damn I just left a bunch of it at my old house. Anyway. so you're running that under the wall frame? Thanks for the advice, I'm starting to put some of the pieces together now. Have a great 4th of july -HB

Yep - the insulation stuff is sticky on one side - I just stuck that to the bottom of the wall frame - I also used the same stuff along the studs before the drywall was screwed up. The stuff is around $5 a roll at home depot in the plumbing dept. I caulked the floor and the ceiling before bashing up the wall. You just bash the hell out of it checking with a level until it is up correctly. Just to repeat - when you build the wall frames - really check the stud length for each stud & adjust - this really can have a big impact on getting the wall up. The first wall that went up in my studio was labelled "The wall of shame" - it was a bitch to get up and had to be adjusted while caulk was drying - no fun.

You just bash the hell out of it checking with a level until it is up correctly.

Ah precision, yes this sounds like the type of job I can let my dad help with. He's a major "corner-cutter" so I'm not letting him near most of this project. I can see that play-mat stuff in your picture also. When you say to adjust at each stud, you mean that at each stud I'll have some of that play-mat between the wall and the ceiling, maybe 4x4 square? And that some studs may only require one piece of mat, while others require more? Did you ever have to split one of those mats in half? My understanding is that you need at least 1/4" gap in order to be able to get the wall to clear the ceiling when erecting it. So I suppose I could have up to a 1/2" gap there, maybe more. Those mats that I saw were about 3/8" deep, and I would want to compress them to about 1/4" I suppose. I went to HD today and looked for acoustic caulk, as I suspected nothing was actually labeled "acoustic caulk" or even referred to sound control. I did find some stuff called Dynaflex230, elastomeric latex. Says it stays flexible, which is the main property of acoustic caulk I think. Was this the stuff you got or something else? Got the name of it? thanks, HB

With the playmat along the top of the wall - just glue on one layer across the top of the wall (I used contact adhesive). When the wall goes up this has to maintain an acoustic seal (well caulked of course) - so you don't want any gaps in it. For adjusting - I meant adjust the length of the studs. What I did was lay the header & footer on the ground - measure up for the 1st stud & cut it & then used that stud as a check for the next stud. If your building is perfectly level you should have the same gap at the ceiling (the gap that will ultimately have the compressed playmat in it) - if not, adjust the next cut. On some of my walls the stud was 1 inch longer at one side than the other. Without adjusting the stud length - you'll find the wall will not go up. Of course if your building is perfectly square & level you can just cut all the studs the exact same length. On this photo - you can see the playmat glued to the top of the wall. These photos are of inside out walls - but its the same for regular walls that you drywall after they are up - its just a bit heaver lifting up the inside out walls (a job for your dad to help with :)) Also - after you build the frame but before you glue on the strips of playmat - lift the wall up & check it. For building the frames you will find a framing nailer gun to be the "tool of the Gods". I bought one of those paslode propane framing nailers off ebay for about $250 - well worth the investment.

ok, gotcha on the adjustments, thanks for clarifying for me. I got a couple friends in construction so I'm hoping to borrow them and their nailers for a few days of framing! Oh yeah, how about my question regarding the acoustic caulk? If you can answer of course. Thanks much! -HB

Check your local yellow pages under commercial drywall and insulation contractors/suppliers for the real acoustic caulk, it comes in 29 oz tubes instead of 10 0z, and runs around $4 per tube. Not all contractors will sell to private individuals, but make the effort to find one who will - Andrew, before you jump in and reiterate how good the non-acoustic stuff works, here's my reasoning for this statement: Neither you nor I have built stuff that's been up for 20 years and is still working well - I know the things I built that long ago were done wrong, that's part of why I've been studying this field off and on for the last 25 years. A hairline crack in a sound wall will make a difference in isolation, unlike insulation used for heat control; so a slight crack in caulking can cause problems down the road that you can't get at to fix without tearing out walls - the acoustic rated stuff claims to not do that (I know, so does the other stuff) and it also is supposed to be heavier bodied for better mass. Considering that recommendations are to leave 1/4" gaps between ceilings and wall corners and fill them with caulk (maintains isolation of surfaces, which helps overall TL) I think it's pretty important to use the recommended stuff here - the only time I would consider otherwise is if I KNEW the construction was getting torn out in less than 10 years. My present studio has a 4 foot door which, although not built correctly for best sound isolation, was hung with 4 super-duty hinges on a 6x6 post braced every way but loose - after about 10 years, I had to slightly plane a couple of the door faces because things had sagged enough to change the gaps by about 1/4" in 4 feet - had this been a caulked joint instead of a weather-stripped lip, I'd have been ripping stuff out. Not a pleasant thought. For those reasons, and because aside from a bit of legwork the acoustic rated stuff isn't any more expensive, why take the chance? I like to limit things I do repetitively to pizza, sex, beer, and music (not necessarily in that order) so I don't recommend shortcuts that will force me to add to that list... Steve

soundproof.org sells the acoustic caulk - it's around $10 for a large tube.

Yeah, they're 'way overpriced even for net sites - here's one for less - http://www.acousticalsolutions.com/prod ... /caulk.asp Most people have reported local prices around $3.75 to $5 per tube for the large tubes - about the only thing I found at the local Homely Despot was the large caulk gun, not the caulk... Steve

Wow, that's a much better price than the quiet solutions stuff, 9.95 for 10.5 oz! Thanks for the info Steve, I appreciate you jumping into this thread as well. I just bought this house and I am expecting to use this room for the next 15+ years. I want to get it right the first time (as much as one can), but I'm also not building a high class commercial affair either. So I need to stay practical as well. Caulk is probably oe of those things I can afford to do right, now Overly doors, well... I've got another insulation question, but I'm going to do one more search of the site first, it's probably been answered somewhere already. Basically where to use R-19 and where can I get away with R-11. In the meantime, if you get a chance I've got an outstanding question on my design thread about using the proposed closet for a bass trap and how that should work into my design. If you get a chnace to look at it, that would be great! Link is in my first post in this thread. Thanks! -HB

Noticed a couple of things - your comment about monitoring "loud" - how loud, and why? (yeah, this is a trick question - but you win either way :=) Insulation - for best isolation, using SAFB's or 3 PCF rigid fiberglass or same weight rockwool is best for walls - a gentle fill, with moderate pressure against inner panels (at least near the center of each stud bay) works best - enough pressure to dampen the panel vibrations but NOT firm couple one side of the wall to the other. Quite a few people have had good results from using standard house insulation inside walls - again, just fill it. If it doesn't look like your paneling will compress the insulation AT ALL, you can take extra strips of insulation a few inches wide and glue them onto the insulation running down the center of the batts (not too thick though, you want only moderate pressure on the panels for damping) Gotta go do "fambly" stuff now, more later... Steve

Typically I'll be montiring at 85db as recommended. But sometimes its fun to crank up a mix at the end of a session, or I'll have it louder if I'm tracking bass or something where I really want to feel it. The studio gear is packed right now so I can't do any tests to see exactly the SPL I'm looking for. Maybe 110 max? When I went back through the threads on insulation it seemed you basically said fluffy is ok for walls as long as you overfill (guess that's also what you said here), definitely need rigid for acoustic purposes like traps. For instance in this thread... http://www.johnlsayers.com/phpBB2/viewtopic.php?p=13109. In my design I'll have one double-stud wall built, and its main purpose is soundproofing (this is the splyed wall). But the other 3 walls are against the foudation and underground. In another thread you said that these could serve as "free" bass traps if you just put one layer of sheetrock over them. If this is in fact the case, since these are serving now for acoustic purposes, is it necessary to have rigid fiberglass behind the sheetrock? Right now they have normal yellow fulffy in them. Since these are then really just big panel traps, I should maintain an airgap between the insulation and front panel(sheetrock) correct? Also does rigid have the same heat insulating properties, since this will fill an exterior wall? It also seems from other posts that R-19 is ok for the ceiling between the joists. I'll have RC and 2 layers of 5/8" sheetrock over that. Thanks! -HB

Hashbrown, I just kind of quickly glanced over the thread. Here's a quick pic of what I did w/ wall braces: http://johnlsayers.com/phpBB2/viewtopic ... &start=215 For Insulation, I'm using Roxul AFB http://www.roxul.com/sw34142.asp Or there's also the Owens Corning 703 http://www.owenscorning.com/comminsul/d ... Series.pdf For Acoustical Sealant, there are several mfg's that make it: Boss, Grabber, etc, etc. I'm paying $3.25 for a 29oz tube when I buy it by the case (12 tubes). Find out who the suppliers are for construction materials in your area for (eg: steel studs, drywall, insulation, etc). One of them are bound to carry it. As far as SPL, in a CR, you're probably not going to want to go over 100db. Hope this helps. Aaron

Aaron, I've read your thread a few times, it's a great one! My concern was doing those anti-sway brackets with angled walls. But I suppose I could just angle the entire bracket the same amount. I would have to drill the holes for the joist as I was fitting each one, so I'd know where along the bracket I was aligned with a joist. Now did you secure those into any joists or did you always put another span in between, like in the picture? Ok, so I see that the bracket wraps around the top of the frame, how did you attach the sheetrock to the frame where this bracket would interfere? It looks like you used RC on your walls, so maybe that gave you the space you needed to clear the brackets at the top? I won't be using RC on the walls so I'm not sure how that would work for me. Hey thanks for responding!

Hey Hashbrown, I did use RC on the control room side of the walls, This gave me the clearance I needed. However, I also, before putting up the drywall, shaved about a 1/4" piece of 703 and liquid nailed to the the side of the bracket that was facing the drywall, as kind of a perimeter board concept, just in case the bracket shifted and rubbed up against the drywall. This way it would give a little cushion to reduce any vibrations. Several of the brackets are attached directly to the joists where they run parallel to the wall. On the perpendicular walls, I just put a 2x4 in between the joists so I'd have something to mount the mounts to. Same thing for the angled wall. If the joist just happened to be where I could put the mount, I used the joist, if the bracket location was between joists, I did the same as the perpendicular wall situation. The other question you had about "not using RC". I didn't use RC in my iso booth. Here's what I did, but I'm not sure if it has worked well or not. I did the same mounting method as above. Except on the first layer where the brackets were, I cut out the drywall. Used some acoustical sealant, and also did the 703 padding. The second layer went over it just fine. Providing you're using 5/8" drywall on the first layer. Aaron

Thanks Aaron. It seems that your technique for the non-rc walls would certainly work, good enough for me at least. Especially since that 2nd layer goes over without problem (yes I'm using 5/8"). So now I have to re-read some of that thread and take a look at those designs again. So now I have options from both you and Andrew that allow me to build the wall first or the ceiling first. What to do, what to do.

I'm building my walls first, and then hanging the ceiling from RC "Inside" the walls.

Your comment about 85 dB levels tells me you already know what works, to answer your PM - what kind of monitor system do you have that can play clean at 110 dB? And, if it's not clean, it won't show off anything but instead stands a good chance of losing customers ("what's that? Sounds like crap...") Yeah, the "wow" factor can be impressive if kept under control, but I doubt you'll find many nearfields that will sound good at over 100 dB (which is still pretty loud) - if you want to go much louder, you're talking pretty expensive and large mains or quite a bit of distortion - anyway, as I said you already know how to get your mixes to translate. Insulation - If you're using a single layer of drywall on all your concrete backed walls for the increased bass trapping, you could go to a lot of work and keep your insulation off the insides of the panels, or you could allow it to touch a bit and broaden the panel's response, making for a smoother absorption curve. This would also, however, lower your absorption coefficient at resonance from about .9 to around .7 or so, so if you're calculating ALL your absorption figures for ALL your walls, ceiling, and acoustic treatments, you need to take that into account. One other thing to consider - your room dimensions. If they are going to cause modal problems anywhere in the 50 to 100 hZ range, that's your target frequency for calculations on panel cavity depth - this would override just placing studs next to the wall; panel trap frequency is calculated by the mass of the panel and the depth of the air space (including insulation) - the formula is Fo=170/sqrt of m*d, where Fo is the resonant frequency in hZ, m = surface density of the panel in lb/sq ft, and d = depth of air space in inches. for example, 5/8 drywall with a 3.5" air gap works out to around 60 hZ - with no insulation inside, this peak will be only about an octave wide; with insulation, it should broaden out to around 2-3 octaves usable, with its peak about 20% less than without insulation. The standard way of building panel traps is to use rigid fiberglass - this improves absorption over the fluffy kind, where in regular sound isolation walls the fluffy stuff is almost as good as the rigid. Reason for this is the way panel traps work - externally, they are a pressure device which is why they work best with no air space behind the trap assembly, and placed against a wall or ceiling. Inside the trap, however, different things are happening - the moving panel (caused by external bass wave pressure) tries to move the air inside the trap - in order for the air to move much, it has to pass through the rigid fiberglass insulation, which has a fairly high resistance to gas flow - the bass energy is first absorbed by the work required to flex the outer panel; then, by the air trying to get through the absorbent - sort of a "double whammy" effect. Bottom line - probably the best way for you to use your 3 basement walls for trapping would be to first measure all your room dimensions, then calculate modal frequencies (at least the axial ones), and finally pick a frequency where there are a couple of modes bunched up around 50-120 hZ or so, and choose your air gap depth based on that frequency and the above formula - in almost all cases, resonance of wall panels will cause no discernible ringing, so just gluing rigid fiberglass to the concrete will keep it from contacting the panels and you'll get the most absorption. Speaking of basements, have you come across the "basement from hell" PDF here yet? If not, yell; I forget where it's hiding at the moment. Hope that helped some... Steve

I did a quick search on "basement AND from AND hell", but didn't find anything relevent. I'm curious.

Fourth post down, on this page - http://www.johnlsayers.com/phpBB2/viewtopic.php?t=839 HTH... Steve

Thanks Knightfly. I call that "The Famous Mold PDF".

Thanks Steve, an excellent response! I appreciate you taking the time to explain it. Yep I read "The famous Mold PDF" a couple times a few months ago, it was before I moved into the new house so I couldn't apply it to my situation at the time, better read again. The basement wall insulation was covered in plastic, so I definitely want to get rid of that. I thought about using that landscaping fabric to cover it, so it can still breath, but should keep in the fibers. Its a moot point once I get the sheetrock on anyway (still removing the plastic of course.) Gluing 703 to the brick definitely seems the way to go, but I'm guessing I might want to treat that brick first? I'll re-read the pdf and look for an answer. Modal problems - Since I'm using splayed walls, will that take care of the modal problems? The framing is already up on the exterior walls, I suppose if I need to increase the cavity depth, I could attach some kind of battons(not sure what they be called) to the face of the 2x4 frame and attach the sheetrock to that? Essentially creating 2x6 or whatever depth I need. I think I'm to the point where I just need to start working on it. Probably start a new thread with some pics and questions as I encounter specific issues. Thanks alot guys. Lets see if I can get this 2 month project done by next summer! -HB