John Sayers' Recording Studio Design Forum Archive

You might also be able to "stagger" the drywall layers on the other side, then caulk them just before you lift each section into place, for a better seal. I think it was Lilith that did that on her corners. I might be wrong on that....


- Stuart -

Thanks Glenn, that info will save me a bit of unnecessary work. I think I've seen something here like a silicon rubber or neoprene weather stripping from 3M which will probably foot the bill.

Hello Stuart, I thought about doing something like that but thought it might be a bit precarious - danger of breaking the drywall where the pieces overlap from moving the wall into place. Perhaps if just the outermost layer were to form a lip it might not be so tricky.


After seeing the ceiling insulation which has been applied, I am concerned that my isolation walls should go right up to the concrete to establish an airtight cavity and true MAM construct. It appears I can’t take the insulation down apparently because of building codes or certification (Minergie) so, for the isolation level I’m likely to need (the walls are supposed to have an STC rating of around 50 as they are), and as I’m not doing ‘room in room’ I’m going to make the following compromise.

The main considerations are the breach in the dead air space between the walls, and in the critical corner boundary.
I will take the Isolation wall up to the Insulation, leaving just enough space to attach 30 – 50cm wide MDF or gyproc sheets to form a lip or partial ceiling at the top of the wall.

These panels will be attached and sealed to the top of the isolation wall and will fit snug against the insulation panels affixed to the ceiling (also perhaps with acoustic caulk or acoustic weather-stripping between). This construction should hinder the sound flanking directly over the top of the wall, re-establishing the integrity of the corner acoustically, and increase the insulation path to the outer wall improving the seal breach in the dead air space (perhaps also acting as a kind of ½ meter deep trap).

Keep in mind this a compromise and is not an ersatz for RIR isolation nor deemed as effective as full floor to ceiling construction.

Below is a diagram (not to scale) of the technique I’m considering. Perhaps 2 layers of drywall should be used to match the wall isolation. I would probably need to add 2x2 or 2x4 support members affixed, and at right angles to the studs for stability i.e. hinder sagging. I will also apply a layer of rigid wool on the surface and possibly Masonite pegboard panelling or wooden slats to cover, or perhaps just corner trapping wedges, foam, or wool in fabric.
This lip, or partial ceiling I will form into shallow soffits with layers of rigid wool strips covered with thin pegboard or short slats and then mate this up to the soffiting front and back of the room to create a perimeter around the edge of the studio ceiling, similar to that mentioned in a design on the RealTraps site by Ethan Winer and Wes Lachot :
“For a border, you can use 1/8-inch plywood or Masonite, or even thin plastic or heavy card stock, painted for appearance. The goal is to reflect mid and high frequencies around the ceiling edges, yet allow bass frequencies to pass through to the fibreglass above.” This refers to a technique applied when the entire ceiling is covered in fibreglass panels as opposed, but similar in effect, to a cloud.

This will also give me an edge on the ceiling where I can possibly hide some LED RGB lighting strips for indirect mood lighting.

the simplest option (to me) would be to put isolation clips into the concrete ceiling and hang hat/furring channel then your 2x layers of drywall. keep it decoupled from the walls. i'd also make sure you get isolation brackets to support those walls to ensure they do not tip. Mason Industries, PAC International, Kinetics Noise, etc make/sell isolation clips and brackets that will provide you with what you need. having just the insulation there won't help and adding rigid framing to attach it to the ceiling above will not help either.

Digesting your advice Glenn.
In a previous post you mentioned WIC sway braces, which I remembered from Rod's book.
I thought however that they were inappropriate because of the space between the structures.
Nevertheless, I'm working on the concept I had in mind with the soffits, which may render them unnecessary, and I'll present that soon, then we can discuss it better.

In the meantime, I was on the site and found them putting these sheetrock panels on the attic ceiling. Do you think they would be good for my walls? 1 or 2 layers?

if it can support the weight, then 2 layers.

Thanks Glenn,
Back again soon.

OK, so at long last I’ve finally got the plan going with Sketchup. I’ve been trying to deal with all the little details, and have been ‘baffled’ (;-p) with the speaker mountings for quite a while – the angles have been driving me nuts, especially where they interface with the rest of the framing.

Anyway, I thought I should post what I’ve done so far (planning that is, the construction has not yet begun).
Here with the soffits and ceiling frame. Sway bracing is integrated into the front wall framing. If the side walls are bolted to the front however, they may not be necessary. Here again shown in context with the duct, vents and proposed silencer. I’ve tentatively added a duct to the floor. As these rooms are not heated, and as far as I know, this is an exhaust duct, then should I have to heat the room in winter, it makes no sense to have my costly heat be directly sucked out – the room will never warm up. So in this case I can switch via vents or plenum to have the air exhausted from near the floor as opposed to near the ceiling. Here you can see how the proposed ceiling lip will be supported by the ceiling frame. The cavities thus formed will be filled with FG, plastic film, and perhaps a layer of acoustic tile or slats. Also shown are the front down-light holes. Strips of RGB LED lighting will be run along the ceiling framing sides and rear. Shown here is the finished soffit with the rear down-lights (over the couch position). Since designing this soffit, I’ve decided to maintain the isolation at the egress of the pipes themselves instead of requiring the entire soffit to be airtight, so apart from the sections directly covering pipes, the rest will be soft absorption instead of the OSB as shown here.
Shown too is the encasement for the drain. This will be stuffed full of RW and a layer of rigid FG. Not really visible is an access panel to the drain. Also not shown are the corner absorbers And here with the partial drywall ceiling. The double layer of drywall forming the lip will be screwed into the frame wall and ceiling using screws into plastic plugs as opposed to direct into the wood. And further strips of neoprene (Randdammstreifen) applied for the interface to the ceiling insulation. These strips are not shown complete, and/but may not be necessary anyway

Views from above.

The left and right isolation walls will be constructed in 2 sections each. The sections abutting the front wall will be bolted to the floor (isolating the bolts as discussed earlier. The walls will rest upon strips of something here called Randdammstreifen. The interface to the front wall I am considering either doing it the same as the floor with Randdammstreifen and bolting, or glue a strip of 12mm compressed rigid fibreglass along the stud where it butts against the front wall then backer rod and caulk. The latter idea is shown in the following clip. The inner drywall wall shown (grey) is only a small panel near the ceiling which I will show in a later clip. Also I was thinking here that with the rigid FG, backer rod wouldn’t really be necessary as the FG would itself serve this purpose. Again this section could be bolted if necessary to the front wall. The second section will be bolted to the first section, bolted again to the floor.

Where the sections must accommodate pipes and vents, the contour of the wall will be adjusted accordingly. The missing section of 2x4 will be added after the wall is in place. The rear wall will mate with the side walls using the same technique of rigid FG and caulk

Shown here are the speaker walls and slat absorbers. The speakers are Cerwin Vega E310’s which are directed at the couch position (@ 38% from rear wall although I’m not certain I will even have a couch) in a wide angle. I’m flush mounting these to subdue the bass (ported rear) a little more than is possible with the adjustable X-over. I’ve had these speakers in this configuration for a long time and find them excellent as an alternative listening pair – typically HIFI and different than the monitors proper.
Though in the past they have always been free hanging – I’ve always felt that the Bass from the rear needed a bit more absorption. The main monitors will be on a stand behind the desk in near-field configuration. Here are the hangers. The upper cavity behind the speakers will be filled with loose FG and the speakers allowed to port down to the hanger cavity. I’m still debating on whether the speakers should be mounted in boxes or just on shelves fixed in place with neoprene or foam decoupling. I’m tending toward the latter. I know the port is missing at the bottom of the trap, Haven't gotten around to drawing it yet. The slat walls will be constructed pretty much standard. They will be in two registers – the lower for bass, the upper for mids and highs. The upper section continues to the speaker wall, the lower ends abruptly leaving only an absorber in the wall. This is to avoid constriction of the desk space and accommodate positioning of the desk and isolation box etc. The Sketchup file is 2.1 megs and I can’t seem to reduce it any more so it seems I can't post it.

I’m really anxious to get some level readings but the room has temporarily been commandeered as a storage room for building materials.

Also I bought some ‘Tiefgundierung’ and a big applicator brush last weekend to apply a sealing coat to the walls. Now I’ve seen they’re painting all the cellar walls anyway. Well maybe I can use some of it for the floor and maybe some in our winter-garden.

the key is to remove as many materials as possible and purge the file. if not you could host it somewhere. on the slats - make the front angled panel absorptive. maybe make them shorter with steeper angles and make several of them (saw tooth). on the pipes and ducts - encase them in a soffit which is sheathed with the same isolation mass as your other isolation walls. adding the drywall over the pipe exit won't stop the sound from entering the pipes themselves... same for the ducts.

Studio Turbenthal.Skp

I purged most construction lines and extraneous materials but it's still too large. So I've zipped it and hosted it as you suggested.
The drywall at the pipes in/egress, is primarily to help maintain the walls integrity and remove the need for the entire soffit to be airtight. The pipes themselves are (to be) insulated and I will caulk where it passes through the drywall. I understand that the pipes themselves can pickup the vibrations and must be housed i.e. soffited within the soffit so to say. I did assume however that I could get away with a single layer of drywall or preferably OSB. The duct in the front will definitely be isolated - encased, as you put it.

make the front angled panel absorptive. maybe make them shorter with steeper angles and make several of them (saw tooth)

Basically you mean leave the slats away where the panel angles to the speaker wall? I thought using the slats would help maintain the highs and would also be more aesthetic. Shorter, steeper... saw tooth - are you referring here still to the front angled part? Continuing the slats further back into the room may cause problems with furnishings.

Your SKP file link returned this error:

"Secure Connection Failed

An error occurred during a connection to share.ols.inode.at.

SSL received a weak ephemeral Diffie-Hellman key in Server Key Exchange handshake message.

(Error code: ssl_error_weak_server_ephemeral_dh_key)


The page you are trying to view can not be shown because the authenticity of the received data could not be verified."


Most likely isn't me...maybe

xSpace wrote:SSL received a weak ephemeral Diffie-Hellman key in Server Key Exchange handshake message.

Is that another way of saying it got a friendly kick in the pants and took offence?

I don't know Diffle or Hellman but I used to go hiking with a Duffle bag which often contained Hellman's mayo...

Jeepers'
...and April 1st is already gone...

I've tried the link from a few other PCs - including from work where we've got firewalls and scanners galore, and I've had no problem.

Anyone else have problems with the link?

Your link worked fine for me.