Building rehearsal / mixroom

The inside out wall is appealing to me. Having the studs on the inside of the room opens up possibilities for acoustical treatment without building a lot of extra frames. I have a question regarding the corner of 2 adjacent inside-out walls. The walls are build and lifted into place, how to seal the gap between the walls? I have attached a picture to show the possibilities ( as far as I know) Wood = frame yellow = insulation white = gipsumboards A shows 2 frames with the gipsum and insulation not sticking out, leaving the framestud of 1 wall uncovered B shows the gipsum layers almost touching eachother, leaving a possible tiny airgap C shows 1 gipsum layer and insulation overlapping the other layers D shows the same as C but sticking out a lot more. D doesn't seem usefull at all to me, but the rest do. A is easiest to build. Questions: - Which one is the recommended way to build the corners of 2 inside-out walls - How to seal the gaps between the gipsumlayers with caulk at the back? Or do we need to seal the gipsum at the inside of the frame, creating an airtight seal there instead of at the direct corner of the gipsum layers?

Thank you all for clearing that up for me. I had seen a few posts with pictures of the inside-out walls that did not have any insulation filling the cavity. An assumption on my part. My bad. :P I am now a fan of the I-O wall. And yes, I love the way JS uses slats and textures to create a balanced acoustic environment. Cheers, John

Does anyone have a clue on how to seal a corner in an inside out situation?

bump.

Since my last question is probably to hard to answer ;) I have another question. On one wall, the celingjoist is directly before the wallstuds. The joist are 165mm high, the wall studs 70mm deep. That's a too small area to use a caulk gun to seal the edges. Since we're beefing up the walls, we cannot caulk the extra layers in the area between the celing joist and the existing gipsum layer. Also we cannot add mass on the small part of ceiling there. How to seal such an area/ gap? We can add layers of gipsum all the way to the celing, only not secure them at the top or seal them. ( have started doing that) Should we add more small layers of gipsum to fill the entire gap and caulk the bottom so at least that will be sealed? Or should cover up the gap with something? ( tiney 3 leave happing maybe?) This is all for the outer leaf of our 2 leaf MAM wall.

You are not asking hard questions. What you are asking are, to some of me, questions that should not have to be asked ;) How ever you build or construct your walls will dictate how the corners will be sealed, it is about as easy as that. Often the only way to answer the questions is to simply do the work and the questions will answer themselves. For example, your pictures above when you asked about how to seal the corners of an inside out wall. You dismissed D as being "not useful" when it is the exact way you want to, at least, attempt to build the wall. Continuity of mass is part of your goal with isolation. But all things considered, since I recognize many are challenged when it comes to doing construction, "A" being the easiest, as you stated, is the way to go for many, even if it is the least desirable in terms of mass.

Construction ( at least sound isolation construction) is new to me, doing a lot of reading, learning and checking out other builds. But some parts of a build are not clear to me, as with the corners of an inside out wall, so I'm not afraid to ask stupid questions :wink: Your answer is very helpfull actually :D What I meant with my comment on ''d'' is that's it's not usefull since the gipsumboard will stick out of the frame for several inches, doing nothing usefull at all. I assume the best way to build a corner would be C, but with the insulation of course wrapped around the entire corner as in D. This will have the mass around the corners and the insulation too.

Well, depending on how you guys build in your country, the insulation shouldn't be an issue since it is installed after the completion of the framed walls. I understand your concerns with the corners, based on that, try to make the least amount of voids (holes) in your corners when you build the individual walls. Use solid studs instead of blocks when you make up your corners, if that helps. Do not put something together that creates a hole that you will not be able to get to once the wall is standing up right. Good luck and keep us n the loop,

Thats good advice X. "Void" corners also make it really hard to get the caulking gun in there to seal it all up! trust me I know

Thanks Sister. Lilith's build thread is an ideal example of what you will encounter with an inside out type build: viewtopic.php?f=2&t=11316 Very well documented so should be required reading for anyone needing first hand knowledge and practical ideas about how she was able to get her studio going.

The liveroom will have 2 leaf mam walls, thinking of not going 2 leaf mam wall for the mixing studio. Isolation will ofcourse be a lot less, initial quick and dirty tests have shown the current outer leaf blocks enough noise from outside and blocks the largest part of the music within the mixroom. The ceiling is not beefed up yet , and the leakage you can hear outside the mixroom comes from the upperfloor. After we have beefed up the ceiling we will do some proper tests to see how much is actually isolated. So this is all theoretical ;) I have 2 options for mixroom layout First is the monitors facing the liveroom, with a door between the soffits for the monitors. A window can be made into the door. The other one is flipped 180 degrees, the door in the back. The large beam I posted about will be behind the soffit, will this be a problem? Your thoughts of on the best layout for the room?

Building is a bit on a hold now, injured my left elbow during working the studio. It's getting better slowly, should be back in action in a week or 2 hopefully. Gives me more time to think over the design of the mix/rehearsal room. I have added a sketchup file with scenes on the current progress of the build and a draft for the innerwall of the rehearsalroom and soffit walls of the mixroom. For the mixroom, what will be the best side for the soffit wall? On one side, a door will be between the two baffles of the soffit wall, at the other side of the room a beam will be just behind the baffles. Will only be a problem if we decide to not build the innerframe, we'll decide on that a bit later. Ceilingheight: Should we use the maximum available height for our room or go for the better roomratio? The better ratio has an about 25-30 cm lower ceiling. For the rehearsalroom I'm in doubt if we should splay the longest wall in the liveroom. We intend to put superchunks in every large corner, add clouds on the ceiling and a qrd type diffuser on wall A in the rehearsal room, combined with basstrapping above and beneath the diffuser. How much will be determined after we finish the rehearsal room and have rehearsed/played there a few times ( improving the room over time)

i'd have the baffle wall and window face the rehearsal room. i'd put the entry door into the CR from the hallway not between the baffles. this way you get the hallway as an air lock and it will make constructing this easier.

Good point. So would you go for a room in a room design for the cr? I have to build a wall anyway in the back of the cr, because the beam sticking out leaks to much sound to the upper floor. (I can clearly here the leakage come form the beam)

definitely room within a room for both rehearsal and CR. this way you can fine tune the room ratios and gain extra isolation.

Quick question on doors: We will be building doors starting with sticking 2 plywood 22mm boards together. Should we glue or screw them together? Either option is fine for us. Thanks in advance!

search on super door. although folks here tend to have several approaches - solid core doors with lead, hollow core with sand, 2 exterior grade solid core doors with magnetic seals, back to back; etc. cannot say whether a door from 2x 22mm will suffice but i'm guessing not by itself. you'll want something a much more dense and massive if its a single door. a layer of lead between the 2 would do it.

No, not just 1 door of 2x22. That´s not sufficient ;) We will use two doors back to back. ( 1 in each leaf), beefing them up if needed. My question was if 2 sheets of 22 mm sticked together should be with either glue or screws or both would be fine. Since people mostly start off with 1 solid core door of 44 mm instead of 2 sheet of 22mm.

back to back i think you're good.

Back to topic :) The build has been progressing slowly, but steadily. Build a soffit wall for my speakers as per John's design and added a window. Some pictures of the mixingroom: Soffit front wall: Back wall absorption: The mixing room is nearing completion, I would like to have some input on the frequency response of the mixingroom. Mixing room dimensions ( WxDxH) in cm: 285 x 375 x 258. High peak from 6k and up is caused by reflections of a temporarily tl-lighting and can be neglected. When I removed that light the peak is gone. Any suggestions on how to treat the dip around 116Hz and 300-800Hz? Still have to add the slats on both sides of the soffit wall.

So I used a multiplex sheet as a temporaly desk and the dip around 350 Hz almost dissapeared. Interesting ;)