Need feedback on very small studio design in Loft. Thanks!

Is this a better representation of how it should look from the front? the inside studio has brick wall / 2" gap filled with insulation (air pocket)/ 4" studs (also filled with continuation of the insulation) / 2 drywall slabs (of course connected with green glue) then studio. It's funny because i've read everywhere to go with two leaf, and silly me never even thought that the brick would be considered one of the leaves! My worry was that any sound going through my left wall will be trapped between the brick and the wall, but end up bleeding slightly through the brick to the neighbours place. Does one have to treat the brick with something before building the wall two inches away from it? or does six inches of loosely filled insulation do the trick? Also this same brick wall extended up and connects to the tenant upstairs floor which is old loft wood (nightmare) thanks again, i'm learning so much! I'm also now pouring over studio construction, learning a lot (like that air space includes insulation!) - i have a feeling that studio construction should be before studio design :)..

This whole time i thought there was a six inch completely free air space between two walls (each wall comprising of studs, insulation and two slabs of drywall on only ONE side :) ) - so essentially you would have two sets of insulation staring at each other over a six inch "air only" gap. I thought the whole point of room within a room was to have that air only gap to completely disconnect the walls, but i'm gathering that insulation between them, touching both walls does not count as a connection, is this correct?

Yeah, that gets many people confused! That's why I prefer the term "MSM" (Mass-Spring-Mass) to "MAM" (Mass-Air-Mass): less confusion The basic components are your "Mass" of the one leaf (usually a couple of layers of drywall, the "Mass of the the other leaf (ditto), then the "Spring" (the air space between the two masses, which is filled partially or totally with insulation). The spring is actually a damped spring: the spring is the air itself, and the damping is the insulation. They occupy the same physical space. It is kind of like the way the suspension works on some cars, where the spring is a metal spiral and the shock absorber (=damper)runs down the middle of the spring: they are both in the same place, when you think about it. The frame that holds up each "mass" is only there to hold it up, and it can go on ether side of the mass: it doesn't matter if you put the frames inside the air gap, or outside the air gaps, or one inside and one outside. There only purpose is to provide support. You measure the air gap (spring) between the masses, regardless of where the frames are. So the air gap is just the distance between inner surfaces of the two leaves. That gap needs to be at least 4" to give you decent isolation, and more if you can afford it. And yes, you should try to fill the air gap completely with insulation, if you can. No it does not create a mechanical link, provided that it is the correct density (48 kg/m3) and that you don't jam it in tight. You just want it to fit in, with being compressed. If you shove it in too tight, compressing it, then it DOES create a flanking path, but if you just place it in, using exactly 4" of insulation for a 4" air gap, then you are fine. Of course, leaving a small gap without insulation won't do any harm, so if you have a 7" gap and can only find 6" insulation, then that inch isn't going to be a big deal. But in general, try to fill it as much as you can. You want as much damping as you can get in the wall. Those diagrams show a common way of almost filling the cavity using standard insulation and studs, since that is what is easily available, I guess, but studies show that you get better performance by filling the cavity fully. I don't recall the exact figures, but if you do not put ANY insulation at all in the cavity you lose up to about 16 dB of isolation, depending on the wall. Half-filling the cavity gains you about 10 dB (IIRC), 3/4 full takes it to 14 db, and the last bit takes it to 16. I think that was for an 8" gap with 2 layers of 5/8 drywall on each leaf, but I'm not 100% certain, so don't quote me on that! It's been a while since I read that paper...

the inside studio has brick wall / 2" gap filled with insulation (air pocket)/ 4" studs (also filled with continuation of the insulation) / 2 drywall slabs (of course connected with green glue) then studio.

Yup! Sounds about right. That will give you nearly 6 inches of "S" in your MSM equation, which is pretty good. But don't forget that with 2x4 studs you don't actually get 4 inches of depth, so you can't put a 4 inch layer of insulation between the studs and also a 2" layer in the remaining gap, as you'd have to compress the insulation a bit to do that. 4" of insulation will stick out a bit from between "2x4" studs. So if you make your 2" 'air pocket' a bit deeper, say 2 3/4, then you will be fine.

It's funny because i've read everywhere to go with two leaf, and silly me never even thought that the brick would be considered one of the leaves!

Yup! And brick is a pretty good leaf too! It is very dense (much denser than drywall), so it will be giving you good isolation already. That, plus a 6" gap, plus 2 sheets of 5/8 drywall should give you great isolation. One word of warning though: Seal that brick! Paint it, or plaster it, or stucco it, but do something to it to seal the porous surface. Your leaves MUST be sealed airtight, and brick isn't very airtight on its own. The surface needs sealing. Important!

Also this same brick wall extended up and connects to the tenant upstairs floor which is old loft wood (nightmare)

How is that floor above you constructed? If it doesn0t have enough mass on it already, then you might need to "beef it up" first, before you install your new ceiling down below. And you will need to seal it too, just like for the brick. - Stuart -

The floor above me is beams, then slats over the beams then i assume an air gap then their floor (hardwood, i'll take a pic tomorrow. I can clearly hear my upstairs neighbours, I thought having a double leaf ceiling in the studio with drywall / wood frame / insulation air gap / wood frame / double dry wall THEN four feet of airspace to the bottom of their floor would suffice. Speaking of which i have not even addressed the fact that my floors are the same as theirs, although below me is a rarely used office and nobody has said a word about my music making during the day (heavy bass kick dance music :) ). But my floor is attached to my walls which of course is attached to the floor above. Also what is a good solution for where my drywall and studs meet the brick? as far as creating that airtight seal Stuart thanks again for the responses.

Stuart, John. i have listened and learned Here's an overhead shot, i've stolen a couple more inches here and there and this plan has a bigger layout. 30 degree speakers 6 degree walls 2 inches between walls at their closest point 38% mix position (give or take a %) Q1 - is it safe to say this is the best i'm going to get with this size? Q2 - Will putting the window along the side and slightly throwing off the width cause any problems? should the window say in the front? thank you

I don't think i can afford 12 degrees raise on the inside roof, in this pic i have the inside front wall at 6'4" which is quite low, but even that with the 12 degrees almost hits the roof above. The outer leaf would be an even bigger problem. Can i get away with another option? thank you

Well, partial is better than none! So you have two choices: You can either just do as much f the ceiling as you can at 12°, from the front wall to at least as far back as the mix position, then reduce or flatten it out completely the rest of the way back. Or you can do the entire ceiling at a lesser angle. (Not sure which is better, acoustically, but I'm inclined to prefer the "front part at 12°, rear part at lesser angle" approach.) - Stuart -

There's plenty of room to do 12 halfway back then flatten it out. If I do that I'll have 12 all the way around for the entire mix position. I'm getting there! Thank you!

Stuart or John what is the ballpark budget for a studio like this? if you need any more info to help me asses that let me know thanks :) mg

That's really hard to say! Depends on lots of stuff, such as the price of the materials in your area of the world, the price of labor in your are of the world, the cost of getting permits, inspections, etc., etc., etc. I'd suggest you contract a building contractor in your area, and ask him. He's much more able to figure it out than we are. - Stuart -