CONSTRUCTION HELP, WILL THIS WORK?

Hi all! Just wanted to post a sketch on a partition of a wall/floor construction i've been considering building. The thing is that I have another studio neighbouring mine and they haven't been isolation as much as I would hope for. So now I have to build a room-within-room construction to make all of his low-end dissappear. the music recorded in my section will not be of the type "death metal" and sadly I could have used the space as it's quiet enough for me to record in as it is. So don't think as much about the isolation coming from the room but the noise coming in. On the sketch you'll see a concrete wall indicating the direction of where the main part of noise is coming from, this a wall positioned pretty far away from the other studio (about 10meters with 3 other concrete walls) and I'll also build a vocal booth and a control room in the space between that. So what do you think? will this work or could I do it in a smarter easier way? For instance: Could I just "float" the walls against the concrete with neoprene and then studs and then Gypsum? Also; should the insulation be directly in contact with the floor or should it be liften a bit? best regards andreas / stockholm / sweden

You'll definitely want to remove the gypsum closest to the concrete wall... That's the dreaded "third leaf" that will drastically affect your low end transmission loss (a.k.a. "TL").

thanks for the fast reply. So I could actually just build the wall floated against the concrete wall? And that would give me more isolation from that direction? (TL loss) When reviewing some of the basic calculations for walls I still haven't found anything that could help me, since everybody seems to build walls from scratch and not having partitions in concrete or brick. The essential thing is to get rid of sound coming from outside the room, genereally structureborne. I still need to know if the insulation should be in contact with the concrete (rigid surface) or if there should be some air in between. best andreas

In short, you need mass-air-mass. The concrete wall is pretty good mass by itself, so you probably won't have to do anything to increase the mass on that wall (something we often refer to as "beef-up"). So what you will need to do is have a good amount of space (air) between the concrete wall and your new wall, and then a good amount of mass on the new wall you construct. Your floating floor may or may not be needed. There are many, many considerations in the "to float or not to float" question. One factor, I would think, would be whether or not your floor vibrates when your neighbor is making noise. If it does not, then my guess is that you don't need to float a room. Do you have any measurements of the noise levels at various frequencies (especially the low ones) in your room when your neighbor is making noise? If you're sure their noise is going to be the determining factor, having these measurements will go a long way towards telling you (and us) just how much noise you have to stop, and thus how much air and mass you're likely to need to stop it. --Keith :mrgreen:

Gee Sharward you really are fast! :shock: I completely understand what you're saying. I must admit that I just found out about the fact that all the results on the STC scale is based on frequencies above what we musicians would call low end :twisted: All of this makes sence now when I took a peek at a double wall partition sketch, it sure does things (even on the STC scale) when you have extra layers of gypsum inside the wall. The studio next door IS making my floor vibrate and there's possibly some noise coming from the "chop-shop" (how IS that spelled again) underneath, but their "business hours" seems to be whenever I'm not in the studio. So floating the floor is something that I will do, just in case. To make sure you mean "that" third layer I'm attaching another pic.

Cool -- that's better. However, we have no idea what kind of floor you're building this on. We need details, details, details on that. You may need a structural engineer to advise you on how much weight you can safely add to the floor. I can assure you that having your studio collapse onto the chop shop below will not improve your isolation situation... Although you may inadvertently silence the chop shop by killing them under the weight of your room crashing upon them. :roll: Besides, you may break your equipment. ;-)

Also, what's this "Noisekiller Yellow Glue"? It hasn't been discussed here before. Seems dubious to me. :roll:

OK this sketch will show you.. it's about half a meter or more..I know this since I plugged an old sewerpipe that was left open in the floor. My guess is it'll hold.. NoiseKiller is a dampening glue that you apply when sandwhiching floorboards, you apply it in 1 mm thickness and then it'll expand about two times.. it should work (according to the manufacturer) pretty well and they say that it should take off 16dB from structure noises..which I guess is pretty much over the top..I'll look for the english .pdf for the glue and post it here.. I would still have something cleared about the positioning of the insulation.. should it be the way I showed here or should the insulation"touch" the concrete wall?? If not, how do I make the insulation stay in place and not fall out of the framed studs? best andreas

This is the onlt english .pdf I found on their products, not sure if the Noisekiller Yellow is in there, but it be worth the time checking out.. They also have a room-within-room system that looks pretty interesting but perhaps a bit pricy.. http://www.vibratec.se/pdf/proden22.pdf there ya go.. andreas

Nothing about Noisekiller Yellow Glue or anything even close... But it's Fascinating stuf nevertheless! :D. I was especially intrigued by pages 70-77. So much so that I did some Googling and turned up CDM's full product line of vibration and noise isolation products and systems for the Building Industry, which is full of links to impressive spec sheets. :D According to http://www.cdm.be/documents/highlight/partner-network.xmlthe parent company's Web site, they supposedly have "a network of distributors and partners all over the world" -- although there isn't any contact information for them. I'm surprised we haven't had much discussion of CDM products on this forum. I did a search for CDM, and I found a couple of references from our friend Eric Desart who did write highly of them, although those references seem to have gotten buried over time. I had previously pointed to Mason Industries' products, but their Web site has fallen into such an inexcusable state of disarray that I really don't think they deserve anyone's business until they straighten up their online act. Anyway, as you may have already learned here -- if you do go in the direction of floating a floor/room, make sure to do your calculations so that you have the proper amount of compression on the elastomers... Too little compression and they won't act as springs; too much compression and they'll "bottom out" (if not immediately, then over time, sometimes a very short time) and again won't act as springs. Answering your question about keeping the insulation in place -- you can install vinyl straps across the back of the studs to hold the insulation in place. Any number of items can be used for this. --Keith :mrgreen:

Yup the CDM was what I first ordered from Vibratec, but for a 16 m2 floor they would charge me 1000 Euros; that would include the elastomers, metal studs and a bucket (15litres) of NoiseKiller... too much money for just a tiny floor; but hey, he helped me calculate the weight of my construction (now it's going to be less since i take out one layer of Gypsum :? ) but I think I got a hang of it. The good thing about that company is that I could redo my calculations and they'll tell me which type of Elastomer I'd need. So vinyl strips then.. I guess anything that's not transmitting sound would go. And I guess that goes for the floor too? Do you have Sketchup? I could post the model of the project as a .skp file here... best andreas 8)

Go ahead and post it... Although I personally don't have Sketchup installed on my machine and I won't be doing so. (The computer I use most of the time is a company-issued laptop that I'm not supposed to install any non-work-related software on... That's why all my drawings are done in Microsoft Visio -- not because I especially like it, but because it's there. :roll:)

Andreas, did you miss the part about sizing your drawings UNDER 750 pixels wide? After you do, I'll be glad to take a look. Thanks... Steve

... :shock: a little hard to read the vital info in lesser resolution, but hey, here ya go. Thanks in advance... I'll post the .skp on my own server for download since it'll exceed 150kb andreas

And here's a pic of the whole studio... you may wonder why I put the "live" room to the right, but it has to do with the fact that that's as far away I can get from the other studio AND the ceiling is about 4m high in that room.. in the left section where the kitchen and bathroom is located I wanted to have an office of some sort, even though it is possible to tear down the ceiling and get that extra meters.. been considering that for a while but now it seems that I'll go for a studio with as many combinations as possible. :roll: :arrow: Any input on that design and anything regarding the shape and size of the room is highly appreciated!

You'll definitely want to avoid the parallel walls.

Can you be a little more specific? Paralell? You mean that the room(s) shouldn't be squared? Or do you mean one specific wall in the model? best andreas :o

If you look at these designs, I think you'll see what I mean. :)

errr. no, do you mean that if I would angle, say the walls in the right room a couple of degrees that would give me a higher reduction of sound? I'm not looking for a room that is sounding like a "studio". You know, no reflections, totally dead acoustically and generally bad sounding. All the studios I've been to that I like have no or very little absorbers and dead walls. So if by putting the wall a bit off angle will give me better reduction of the sound trying to get in. And that it has nothing to do with the way it changes to sound of the room, I'm all up for it. :wink: My idea is to make the room as big as it can get and THEN treat it with absorbers in case I get "standing waves" or too much low end. So I think I'll try to run the walls paralell to the walls.. So accordingly this pic would illustrate what you mean?

For example look at that SAE college plan called "The garage studio 2" and you'll see what I mean, all of that space is rectangle except perhaps the walls of the control room.. I can't see that angling the walls to the outer walls would make any difference in reducing the outer noise. best andreas

Nope... That's not what I meant. Make your inner shell parallel with your outer shell. (In other words, don't do what you just illustrated there.) But then angle the walls so that you don't have rooms consisting of parallel walls. If you don't care at all about the acoustics, then it probably doesn't matter.

Angled walls (as in, opposing walls NOT parallel to each other) has two main purposes - one, when angled a total of 12 degrees or more from each other, it stops flutter echo in the room WITHOUT the need for absorbents on those two walls, and (2) when angled even further, with the wider distance to the rear of the room, it can create a REflection Free Zone at the mix position - this is assuming that you are NOT mixing surround, and that you actually draw the geometric plan so any direct sound from either speaker reflects somewhere OTHER than back to the mix position. Splayed walls have NOTHING to do with isolation between rooms or to the outside, other than: if you make the air space between inner and outer masses LESS in order to splay walls, this narrower air gap will hurt isolation by raising the mass-air-mass resonance of that wall. If you want a more live sounding room, then properly angled walls can allow this WITHOUT the flutter than normally accompanies un-treated, parallel walls... Steve make the room as big as it can get and THEN treat it with absorbers in case I get "standing waves" or too much low end. There is no "in case", you WILL have standing waves in ANY room, regardless of shape. It's just harder to figure out WHERE they will be til the room is built, when you do non-parallel construction. Likewise, you WILL need bass traps in ANY room smaller tnan an auditorium, this is just part of "small room" acoustics. BTW, we're not talking about the inner and outer walls being non-parallel with each other, we're talking about the opposing INNER walls being non-parallel - IOW, your inner walls would form a trapezoid with the speaker end being narrower than the rear wall...

Thanks, that's what I wanted to know. I understand the idea of having a room without constant distances between walls but I mean, we talk 16m2, it's not big, so I need every m2 i got. So I guess the best way to do it is to make it square on the outside (facing the outer walls and on the inside I add angeled walls.. or.. I do as SAE sais..

Yeah, that's better - BTW, what happened to your drawing on the first page of your thread? Seems to be missing entirely now... Steve

So it's better to do it as depicted or could I just add angled walls inside a squared isolated room? Well the first sketch was wider than 700pixels and larger than 150kb so I had to make it smaller as you told me so, hence the bad and small and almost unreadable image on the first page. But I could try to put a new version of it here... let's see..ok here, this is the first one WITH the third leaf.. Also it has all the floor insulation touching the floor..which it shouldn't..correct? best andreas