John Sayers' Recording Studio Design Forum

Dan,

Sorry Sherlock - me on the left - my bro's a guitarist, can't you tell!!

Just a side note about the inside out walls regarding Keith comments a few posts back now I have actually stood one wall.

I was really surprised how tight the wall was when we actually stood it up. I had to really belt it into place with a heavy mallet to make sure it was straight with a level. The rubber top and bottom has compressed really well to make a nice tight seal.

I doubt if I could actually get it more stable if it was attached (read nailed or bolted) to the floor and/or ceiling. It is a very sturdy and stable wall and there is no way it can move.

I think once I stand the other three walls and screw them all togeather it will be really really solid - Its the ceiling and floor that are my real concerns. It's a fine line between headroom and isolation and I keep changng my mind like the wind!!

JohnG

DAMN

If that wall is wedged in as tightly as you say, then I doubt there's much benefit to the rubber. It seems it's so well compressed that it's "shorted out."

I'm also concerned about the long-term nature of the compression. Yes, it may be very tight and snug right now, but over time it may start to wiggle loose.

It probably does make a good seal, but I don't know -- something tells me I wouldn't want to rely on the "wedge effect" to keep the wall standing for years...

All good points Keith,

I checked the rubber this morning and was actually surprised that there still is quite a bit of give in it still (seems to be anyway). I found once you got it over a certain angle of attack with the wall and actually got the wall straight it compressed less / more evenly as there was more surface area touching the ceiling and floor. I am also going to caulk it well to provide another "barrier" of seal.

I think it will "settle" as you say and longterm who knows - we will move again in the next five years so it will be some elses problem anyways!!

Will keep you posted once the other walls are up, I have to do something about the ceiling and floor anyway and this extra mass I put there will cover over the rubber anyway. I think all the rubber proably really does is help with some vibrations going into the ceiling and floor, if I have acheived that then it's probaly worth the $60 for the rubber and glue!!

JohnG

A couple more photos to share especially for anyone thinking of using the inside out wall system:

Photo one: Wall on the floor ready to stand,
Photo two: Cross-section shot showing rubber on studs, 5/8th plasterboard, air/insulation and beefed up original wall.

JohnG

window and door openings on the live room side, there is another wall to go slightly in front of this for the control room.

Just a quick update,
Furring channels on the ceiling "Hex" screwed into the timber battens above.
Next is a layer of 25mm rigid insulation inbetween these channels and then two layers of 13mm soundcheck plasterboard (5/8th equivilent mass)
JG

john,

looks like you are going to have drywall, a very small airgap, and then more drywall. are these two layers of drywall your two leaves? i guess you are hurting on headroom so maybe that's the case.

(i hope that's not supposed to be one leaf, because it's two).

but if so i wonder why you're using hat channel rather than resilient channel. hat channel doesn't offer much in the way of decoupling. so IMO you're creating a resonant space without getting much if any benefit.

also i wonder about the wisdom of having such a small gap, since you will have a very high mass-air-mass resonance that will cause a dip in isolation at that point, and below that frequency the two leaves will basically act as one anyway.

so in essence you'll get the problem of having the mass-air-mass resonance dip but few of the benefits of decoupling the leaves, since the decoupling will only help you above the mass-air-mass resonance frequency.

you may be better off with one thick leaf rather than two poorly decoupled leaves. you'd have to look at some tests and do some calculations to be sure, but i wanted to alert you to this.

sorry if i missed some details on your ceiling construction, i didn't see them.

dan

Ditto what Dan just said!!

Guys,

thanks for that - I thought it may raise some eyebrows!!

(1) Yes, headroom is a major issue, I just could not lose 100mm on a false ceiling.

(2) Isolation - although important to a degree my close neighbours are 25 feet away and I will only be tracking drums early evening and weekends.

(3) John came up with this idea, he said he used it in another studio and it worked out OK. I know it's not ideal but I need the space to be workable and it was the best solution we had as I did not want to rip down the existing plasterboard and there is no access to the ceiling cavity. I am guessing John S. saw it as kinda mass air mass although it is connected by the hat channel and the space is small. Knowing him he probally disregarded this 10mm plasterboard you can see!!

Time will tell here I guess.

PS: Had a little daughter today; Gorgia Frances Grace - 8pounds,4

PPS: there are decoupling clips between the channels and the original ceiling not that it makes alot of difference probally, but I just wanted to point out the channels are not "hardwired" the ceiling diretclly.

JohnG

congrats on the baby, john!

dan

If you have resilient clips along with the hat channel, isn't that actually a little bit better in terms of performance than just RC? Just curious.

Yes, that's true... But they're designed to be used on open joists, not an already finished ceiling. If on a finished ceiling, the gap is so small that the benefits of the air gap are hardly realized.

Congratulations John!!!
(I think that deserved a little more prominent mention.)


Frank

25mm (1") semi rigid board 48kg/m2 up in between furring channels

double layer of 13mm noiseline board next.

JG