Airspace for small control room

I have a space for a control room that is 15' x 14.5'... After creating several layouts I think I'm finally happy with the one I've attached below. However, I'm concerned about the size. In the illustration The pink area is 4 inches of insulation lining the entire inside of the existing cement block structure. The light blue area is airspace. My question is "should I lose the insulation in exchange for a larger room space?" I read somewhere that it would be more effective to make the room as large as possible and simply add another layer of drywall than to give up size for insulation . Any thoughts?

You room is backwards. It should be narrower at the front (where the speakers are), and wider at the back (where the door is). Regarding your actual question: leave the insulation in there, assuming it is something like mineral wool or fiberglass. You need it, and 4 inches is the minimum you need (or rather, a 4 inch air gap is the minimum you need, and filling it entirely with insulation is a good idea, provided that you don't cram it in so much that ti flanks). However, if that insulation is polystyrene or other closed-cell stuff, then rip it out and replace it with mineral wool or fiberglass. Also, why are you flipping the drywall from the outside of the studs to the inside of the studs and then back again? It makes a lot more sense to leave it all on the outside (the side of the studs facing the wall cavity, not the side facing the room). That is known as "inside out" construction, and has a number of advantages for small spaces. Finally, it looks like your mix position seems to be very close to the 50% mark of the room, which is a bad idea acoustically. It should be around 38% (roughly). - Stuart -

Thanks Stuart... I've actually made another design since this thread and I've fixed the backwards room and some other issues. I'll post a picture as soon as I'm finished. Yes, the insulation will be mineral wool. The reason for switching sides with the drywall was my attempt to keep some reflectivity in the room by having the drywall on the inside in some places. Maybe that's not a good idea, eh? The entire floor will be stained concrete btw.

The reason for switching sides with the drywall was my attempt to keep some reflectivity in the room by having the drywall on the inside in some places. Maybe that's not a good idea, eh? The entire floor will be stained concrete btw.

Yeah, I think it would be better to keep the drywall all on one side of the studs, for several reasons. You can keep the room live by using John's famous slot wall designs on the room side of the studs. They'll do the trick all right. The stained concrete floor will help too, and if the room ends up being too live then you can always do simple stuff like scatter around some throw rugs, or suchlike. From your original diagram, it looks like you have a sort of hinged gobo that covers up that window on the left, at the first reflection point. Is that what it is? Nice idea! Keeps the view when you want it, but covers up the glass when you need accuracy for critical listening. One other suggestion I'd make: the "soffits" around your speakers are too small: they won't be very effective like that. Make those panels around the speaker as large as you possibly can. The theory is that you want the panel to act as an "infinite baffle", so it needs to be very large to deal with low frequencies. It also needs to be very solid, dense and massive. So you should extend those flat pieces "between the speaker and the side walls) out at the same angle as the small part that you have directly around the speaker. That will take those "soffit" panels almost up to the window / gobo on the left, and the same location on the right. Those soffit panels should also extend vertically as far as possible, both up and down. You can use the space behind those panels for bass trapping, hangers, etc. And don't forget the ventilation ducts for the speakers, if you plan to use active speakers! Search the forum for John's design of flush mounted speaker systems, and you'll see what I'm talking about. - Stuart -

Thanks for the tips Stuart. Yes. that's an absorber that I planned to put on drawer rails so I could slide it over for mixing. A hinge might be easier though, I haven't decided yet. Anyway, I redid the whole thing and this is what I came up with... ... is this better?

Looking much better! The only thing I noticed on there is that your speakers are not centered in the "soffit" panels: They should be as close to the middle of the panel as possible, in order to get the best 1/2 space effect. Of course, that also messes up your mix position, so you'll have to angle the soffits and speakers a bit more to get the speakers aimed at the right point again, but it will also broaden and tighten your stereo image, since your speakers will be further apart and more centered on the panels. --------- EDITED TO ADD: I have since learned that the speakers should NOT be in the middle of the soffits, but rather offset to one side or the other, in order to avoid creating peaks and nulls in the frequency response. It seems that a position about 2/5 of the width is good. They should also not be centered vertically, for the same reason. - Stuart - ---------- Also, you probably don't need the diffuser on the door, since diffusers don't accomplish a lot in small rooms, and you will probably need more absorption on that rear wall anyway. Apart form that, it looks good, at least to my eye. Maybe others can offer additional opinions. - Stuart -

Here's my latest update on the control room. The vocal booth is just a rough sketch. But another problem I have is that the to rooms are seperated by a concrete block wall. I don't want to create a 3rd leaf by building another wall so I did a sketch of something I think might work. Does this look like a good idea or is there a more practical way of isolating the room without creating a 3rd leaf? Or will this even be isolating the room at all? Keep in mind I have no intention on taking the cement wall down unless I absolutely have to. The only part I plan on knocking out it the space for the window.

Your diagram shows it as TWO separate concrete walls (the red ones) with an air gap between them, but I guess that should just be one single wall, right? Or is it a cavity wall of some type?

Not knowing with any certainty that jonkr lives in America but I do have a strong thinking that he does. That said, we have a saying in the U.S of A, obviously he missed the legislation: "More walls then the law allows".

Soundman2020: sorry about the confusing illustration. The red is 4 inches of mineral wool lining the inside of the existing cement walls. The white space is the wall made of 8" cement block. I'm kind of a newbie with sketchup and it wouldn't let me color it in. xSpace: Yes, i'm in the U.S... Baton Rouge, Louisiana. I guess I did miss the legislation :lol: But I've been doing an insane amount of reading and researching over the last few weeks and everyone seems to say that more than two walls is bad. Am I misunderstanding something?

More than two leaves is not optimal. You may have seen it said as a 3 leaf? It isn't the end of the world, but it is an avenue for a person to get educated because it can apply to so many areas and at almost any time! Anywho, please REREAD the stickies and apply what you learn to your pictures...they are entirely too wide for this forum, and going side to side and left to right has been known to piss the forum owner off :).

Well thats good to hear because I dont think I have many other options. Sorry about the picture size. They fit on my screen without scrolling but I guess some users have a different resolution. I'll resize them. Stuart: Here's a picture to give you a better example of what the space is like right now...

OK, now I get it! Like xSpace said, a three leaf wall is not optimal. You get poor low frequency isolation with three leaves. Much better to only have two leaves, if you can. But on the other hand, you also have to live with what you've got, sometimes. If you can't get rid of that wall, then you'll have to make the most of it. Fortunately, it is solid concrete, and nine inches thick, so that's a good start! That alone will give you fairly decent isolation. So i'd suggest that your best bet might be to just build the "booth" in the same way you build the control room: room-in-a-room, not touching the walls or ceiling. Yes, that will be a three-leaf wall, but you don't have a lot of choice. You'll have to live with it, and to be honest I don't think it will be a major issue, since you have a LOT of mass in that concrete wall, the mass will be in the MIDDLE of three leaves (which, as Eric explained a few days ago, is the best place to have it), and you can add additional mass to both of the other rooms, as well as leaving larger air gaps in the walls, to compensate for the low frequency TL reduction. It should work just fine, especially considering that it is only a vocal booth, so there won't be too much loud stuff going on simultaneously on opposite sides of the wall. I wouldn't sweat it too much. Wider air gaps, more insulation, an extra layer of drywall around both rooms, and you'll probably be fine. - Stuart -

Thanks again Stuart. I can't thank you guys enough for all of the help... I think I'm gonna just take your advice and build it like the control room. I agree that not too much sound should be able to pass through that thick wall. Well, I guess the fun part is over for me. Next up... Wiring and HVAC plans :shock: