Basement recording studio in Columbus Ohio Build Diary

You will have to ask Glenn what he has in mind but any direct connection will be a negative. Just because there is a supposed break via a neoprene slip, the direct hard connection you make with the fastener will couple the two assembles together. Rubber bolts:? :) Do not exist!!!

I will be working on using rubber bolts to decouple the walls tomorrow night. Per Glenn

1/4" bolts, 3 1/2" long, 1" diameter washers, wrap 1/8" around the bolt so a 1/2" hole. the bolt allows you to selectively tighten until you get the balance between hard contact/stability and decoupled. space them about every other joist or 32"

And here's more detail on how it will work from Glenn

the bolt is metal, there is a rubber washer under the metal one and a tube around the bolt long enough to keep it from contacting the runner. the neoprene should be just snug enough not to move and loose enough not to form a connection to the upper joists.

Makes sence to me once I thought about it. I will post pictures to make sure I am doing things correctly. I will also be moving the walls out a inch from the concrete walls. Hopefully this will get me back on track.

Esco wrote:

the bolt is metal, there is a rubber washer under the metal one and a tube around the bolt long enough to keep it from contacting the runner. the neoprene should be just snug enough not to move and loose enough not to form a connection to the upper joists.

I can see how this would work, however there is a certain challenge that exists doing this... In any case where there is a rubber member that cushions an (otherwise) hard connection, the compression of the cushion is critical to assure isolation...... If the rubber is compressed either too much or too little - the isolator becomes a transmitter...... It is for this reason that items like the WIC isolators sold by Mason Industries are manufactured "pre-loaded" - with exactly the right amount of compression to assure their center frequency is 10Hz. I would seriously suggest that you consider purchasing a mechanics stethoscope in oder to make certain that there is no transmission between the various assemblies......... Install everything loose fit - then begin to draw everything into place - in much the same manner as you would as drum head - while checking with the stethoscope to determine exactly when you have reached your goal. In order to determine that you can have someone tap on the existing structure with a 2lb hammer while you "listen" through the stethoscope to make certain the taps are not being transmitted into the isolated room's structure. Rod Gervais GIK Acoustics Director of Education http://www.gikacoustics.com (USA) http://www.gikacoustics.co.uk (Europe) Tel.(US)[removed] Tel.(UK)+44(0)20.7558.8976

Hey Rod, Thanks a ton on the reply! Where would I get a mechanics stethoscope? It makes perfect sence what you are stating and I would hate to just tighten the bolts until it "Feels right" LOL. I want to build this recording studio the correct way so any advice is welcomed and I can assure you that I will take the time to read the comments and document the progression of things as I learn. I have your book, Glenn referred it to me. Amazing stuff. I'm very much a newb so it's sort of difficult to wrap my head around things but this community and yuor book helps to get me on track. Thanks again!

Esco, You can pick one of those up at any auto parts store - they are not expensive. I own a couple of them - use them all the time when doing framing inspections on (local) studios I design........ Rod Gervais GIK Acoustics Director of Education http://www.gikacoustics.com (USA) http://www.gikacoustics.co.uk (Europe) Tel.(US)[removed] Tel.(UK)+44(0)20.7558.8976

Rod, Awesome! I'll get one this week. So I'm guessing that there will be some noise transfer when tapping the supporthing structure above right? So I will be looking for as little noise transfer as possible when determining that things are tightened correctly right? Makes sence! When connecting to the concrete will i use the same concept or does it not matter when connecting into the concrete?

I just wanted to attach the design concept from Glenn to this post so everyone can see what I'm working toward. Here's a top view with material list Here's the control room Here's the rear control room Vocal Booth window view Vocal booth door view This is all documented in the Studio Design section at this link http://www.johnlsayers.com/phpBB2/viewtopic.php?f=1&t=15301

Esco wrote:

Rod, Awesome! I'll get one this week. So I'm guessing that there will be some noise transfer when tapping the supporting structure above right? So I will be looking for as little noise transfer as possible when determining that things are tightened correctly right? Makes sense! When connecting to the concrete will i use the same concept or does it not matter when connecting into the concrete?

When I inspect the rooms I design I expect there to be no transfer of sound from the existing to the new inner structure (as relates to physical flanking). If I can hear the hammer strikes using a stethoscope then they screwed something up and I then search for (until I find) the problem and make them fix it....... I do this at various locations throughout the room - and test right next to me - as well as around the room for each location. As far as the concrete goes - it is every bit as important there as it is anywhere else...... Although concrete is a pretty decent isolator (due to it's mass) at low frequencies - it is a very good physical path for transmitting certain signals as well..... Check it out for yourself - have someone go outside of your home and tap (very lightly) on the concrete - you will hear those taps quite clearly inside - without using the stethoscope...... I have seen tapping sounds travel hundreds of feet through a reinforced structural concrete slab (picture 12 inches of concrete with loads of thick rebar mats - the rebar 12" on center in both directions, mats top and bottom, the slabs poured directly on earth), into a massive pile cap - up through the 14" concrete wall resting on that pile cap - with it finally creating a ringing sound coming from a galvanized steel guard rail 3 stories up (outside of the building). I was standing about 50 feet from the guard rail when I heard it..... Rod Gervais GIK Acoustics Director of Education http://www.gikacoustics.com (USA) http://www.gikacoustics.co.uk (Europe) Tel.(US)[removed] Tel.(UK)+44(0)20.7558.8976

Wow thats insane! I would have never thought concret would travel sound so far! And I didn't realize how important it is to isolate the concrete areas also. No sound transfer at all ehh? Ok I will work toward that. I'm thinking it will take some tinkering around to ensure that I do it correctly. So do I do the bottom of the wall the same as the top?

Esco wrote:

So do I do the bottom of the wall the same as the top?

I would guess not - to begin with you will not be creating a situation (with the wall resting on the slab) that you are creating with the top of wall and connections to the concrete wall. At the existing floor joists and wall to concrete wall connection you are creating specific point connections - very much akin to what created the effect I was describing above - a concentration of energy that is being transmitted, whereas with the plate at the bottom of the wall you have something that is transmitting the energy in a more dispersed manner. The energy is more spread out- much less concentrated......... To witness this simply place a 2x4 plat on the surface of your slab and tap both on it - and on the slab adjacent to it with that same 2lb hammer - listen in the middle of the floor with your stethoscope - you will hear a tremendous difference between the 2...... You also will not have (on the slab in your space) the same point to point type of impact noise I was speaking of in that high rise........ Rod Gervais GIK Acoustics Director of Education http://www.gikacoustics.com (USA) http://www.gikacoustics.co.uk (Europe) Tel.(US)[removed] Tel.(UK)+44(0)20.7558.8976

Thanks! So does this mean that the bottom of the 2x4 wall I can just have the wood resting directly on the concrete or would I use the neoprene as a "barrier"? Also would I bolt the wall or simply use nails? I will be working on this tomorrow so I just want to clarify. It sounds like the concrete slab will even and disperse the sound better.

Esco wrote:

Thanks! So does this mean that the bottom of the 2x4 wall I can just have the wood resting directly on the concrete or would I use the neoprene as a "barrier"? Also would I bolt the wall or simply use nails? I will be working on this tomorrow so I just want to clarify. It sounds like the concrete slab will even and disperse the sound better.

Esco, You should not need the barrier - and nails are fine- Rod Gervais GIK Acoustics Director of Education http://www.gikacoustics.com (USA) http://www.gikacoustics.co.uk (Europe) Tel.(US)[removed] Tel.(UK)+44(0)20.7558.8976

Ok thanks for the info!

probably a bit late - i agree - using proper isolation mounts is the best approach however with tight budget my proposal was to provide moderate decoupling using the bolts. anyhooos - here's the approach in more detail...

Ok I see. Thanks Glenn! I will build to these specifications!

gullfo wrote:

probably a bit late - i agree - using proper isolation mounts is the best approach however with tight budget my proposal was to provide moderate decoupling using the bolts. anyhooos - here's the approach in more detail...

. This diagram shows the wall being bolted to the floor and the ceiling? Why would you do that when there are way to many options to eliminate this type of connection...hard connection.

What are some other options? And would the options save me money and be a bit easier? I am willing to try something different as long as I have a visual on what I am doing.

i believe Brien is referring to using OSB on the corners to form a cross-bracing to stabilize the isolation walls - which is definitely an option, or using (as recommended by Rod and Brien) using proper isolation brackets to stabilize it. the latter will cost more but is also more likely to assure a stable structure, the former "should" be plenty because the rooms are joined on 90 degrees and that join plus the vertical OSB on the corners should do it. either way you need the floor anchors. being that i only really trust things when they are screwed or bolted, i have proposed the decoupled bolts approach used in both the lower and upper plate. one option is to put the OSB sheets on the corners (a 4x8 1/2" sheet nailed onto the outside portion of the frame - in the corner with the meter cut an opening) and then if you find any concerns regarding the stability, add the bolts on the top side. on the treatments walls - you'll still need to anchor top and bottom.

I do not know what a "decoupled anchor bolt" is or where to find it, and still have concerns about how best to use it since a particular foot pound would be required for tension, correct or no?:) I always have concerns about attaching directly to the existing structure since this is most always a flanking path, in respect to the framing at the top. Wouldn't it be, well not easier, but less flanking to attache the treatments to the wall assembly directly rather than the overhead joist/blocking? I assume you have designed this before for someone Glenn and it worked...but those details about how it worked...I'm just asking :)

So would the ceiling be attached to the Joists above or would they be build on top of the walls?

i've used the decoupled bolt tactic in a number of studios and it seems to work. ideally you go with isolation brackets and do it right but many folks find the extra $/mount is more than they can budget, so using a neoprene "washer" and either wrapping the shank of the bolt with neoprene or a neoprene/foam tube, you can avoid most of the hard contact and then you tighten the bolt until you get it just snug enough to avoid most transfer. but not too tight, or to your point, you end up with things directly coupled... the treatment walls - you could free stand with a mount to the walls (a small frame will do it) or sometimes its easier to screw it top and bottom. i use both approaches. the frame method esp if i need to seal in cavities. most times the treatment walls are less weight and the extra anchoring is less of an issue.

I like that. I wonder if it could be modified a bit to reduce the real ability of short circuiting under the present state. The use of a foam sleeve isn't helping, period. And the neoprene washer, depending on friction and tension, can still slip. Well, the lug may not slip but the wall plate can move which makes this connection anemic. Once the plate bolt diameter is determined, 1/2" may be a base line in this respect, the plate would be drilled out using a bit at least 1/4"-3/8" inch larger than this 1/2" inch bolt completely through the plate. If you would have the actual neoprene washer size, bore a hole in the plate to that size/diameter about, well, depending on the height either 1/2 the height or to a depth that matches the height of the neoprene washer. We are trying to create a pocket for the neoprene washer to fit into in order to remove the ability of this technique mentioned previously, to short circuit over time. What you wind up with is the neoprene washer is secured to the plate, if the plate moves the neoprene washer moves, and then the 1/2" red head or what ever is being prescribed, has room to move around without making a connection to the bore side wall, eliminating the foam, which is not doing much but making us feel good by prescribing it. I sketched it up, but I think you can get it and may even understand how it will be a more effective connection...without any data that supports either one of us :) Granted this connection is not to be used by everyone...It should still be either stamped or code approved depending on your geographical location.

You hated my suggestion:(

Sorry all, I only have internet at work now :( So I'm going to do my best to do things the right way but with me not being able to get on and verify things as much it's gonna be hard. I will post pictures as things progress.

I have an issue… actually a few issues. I built the control room top and bottom walls and hammered the walls directly into the joists about 3 weeks ago. Well, when I went to correct the problem I realized that we used a rivet nail driver on the bottom of the 2x4 walls to shoot nails into my concrete to ensure that they don’t move…. Well the issue is that I can’t get the nails out. So now I have the top wall (behind where the speakers and slats are) and the bottom wall where the hvac silencer will be stuck and I’m not able to move the 2x4’s. Can I leave these two walls this way or is there anything I can do to eliminate sound transfer without having to tear them down??