Soundroom in Denver | John Sayers’ Recording Studio Design Forum archive

Hi, I'm building a 16x8x10 soundroom in Denver, CO looking for a little advice. (pics coming soon) The room will be used to record people talking and not bands jamming out. It's on the second floor in a quiet building. We'll be putting the soundroom in one corner of an existing room. The existing 2x6 walls are unfinished on this side and I plan on framing next to them to create a little more air space. The original plan/budget was to use 1 layer of Quiet Rock (~$50/sheet) on the inside and 1 layer of normal drywall on the outside but I was told we'd do better layering more drywall and using GG. My plan is as follows: Walls: double 2x4 stud with batt insulation and 1" gap. inside- 2 layers drywall with GG outside- 1 layer 5/8" drywall The plan was for the walls to be parallel, but I'm thinking the acoustics would be better if they weren't. Thoughts? How much of an angle between the walls would actually achieve meaningful results? Would I be ok leaving out the RC? The Quietrock people said with QR you don't need it so I haven't ordered any. Floor: layer of SheetBlock on sub-floor, thick MDF, padding/carpeting Ceiling: Looking for better acoustics, I'm planning on vaulting the ceiling starting at 8' on both sides, coming to a point in the middle of of the 10' ceiling. It too will have 2 layers w/GG. Will that help or is there a better design? Doors: Thinking about using a THX (STC 51) 32" door. It's on sale for about $2500. Is that worth it or is there a better option out there? Any advice/suggestions are greatly appreciated. Thanks. Thomas

Hi Thomas, There is an announcement at the top of the forum about what to do to assure getting as many responses as possible. The announcement leads to this post (click here). Actually, several people, who are experts on this forum, will most likely not reply if you don't do what is written in that post. Many others who are very helpful, will most likely not reply out of respect for the moderators' wishes. Anyway, some comments:

Walls: double 2x4 stud with batt insulation and 1" gap. inside- 2 layers drywall with GG outside- 1 layer 5/8" drywall

But you said that you already have an existing unfinished 2x6 stud wall surrounding this room, so why would you want to put drywall on BOTH sides of your new stud wall? That would make a triple leaf wall! :shock:

The original plan/budget was to use 1 layer of Quiet Rock (~$50/sheet) on the inside and 1 layer of normal drywall on the outside but I was told we'd do better layering more drywall and using GG.

Exactly. Forget the QR. It is just expensive mass. Ordinary 5/8 drywall also has a lot of mass, and two sheets of that with GG in between will work great. But putting the third leaf on the other side of those studs will negate most of that, making it worse again...

The plan was for the walls to be parallel, but I'm thinking the acoustics would be better if they weren't.

"Better" for what? Is this going to be just a vocal booth, or more like a live room, or is it going to be a control room too? Splaying walls can be done for any of several reasons. For a vocal booth, you might want to splay in order to reduce flutter echo. For a control room, you might want to splay for that reason, and also for creating an RFZ, or even in an attempt to change modal behavior.

How much of an angle between the walls would actually achieve meaningful results?

For flutter echo, generally 5° minimum seems to be the rule-of-thumb recommendation, and usually 6° (per wall).

Would I be ok leaving out the RC? The Quietrock people said with QR you don't need it so I haven't ordered any.

Using or not using RC does not have anything at all to do with using or not using QR! Nice sales hype :) ! RC accomplishes only one thing? it decouples one leaf of your wall from the other leaf, period. Since you are going to have a decoupled second leaf anyway (on your new stud frame), then you do not need to decoupled again, regardless of what you make the leaf out of! And if you were NOT going to use a decoupled frame, then you WOULD need RC to do the job for you, regardless of whether or not you used QR! Either the guy who told you that doesn't have a clue how to achieve acoustic isolation, or he tried to pull a fast one on you....

Floor: layer of SheetBlock on sub-floor, thick MDF, padding/carpeting

Forget teh carpet. Bad idea, acoustically. Carpet is a selective absorber: it absorbs some frequencies and not others. Carpet your floor and your booth will end up sounding dull and boomy. Better to leave a hard floor, such as maybe laminate flooring, then damp the ceiling with proper treatment.

Ceiling: Looking for better acoustics, I'm planning on vaulting the ceiling starting at 8' on both sides, coming to a point in the middle of of the 10' ceiling. It too will have 2 layers w/GG. Will that help or is there a better design?

Height is good, acoustically, so make it as high as you can. But vaulting gives you strange angled surfaces that can do strange things, so that might need treating (especially around the peak). But a key point here is that the new inner-leaf ceiling must rest ONLY on the new inner leaf walls, not touching the existing outer leaf walls or the existing ceiling / roof at any point. They must be two separate, decoupled structures.

Doors: Thinking about using a THX (STC 51) 32" door. It's on sale for about $2500.

If you can afford it, and can install it properly, and if you build the rest of the structure to at least the same level of isolation, then sure, it will work.

Is that worth it or is there a better option out there?

For about 1/100th the cost of that door you can buy Rod Gervais' book on building studios, and it will teach you how to do the entire job, including the doors, windows, walls, ceilings, floor, electrical system, HVAC system, and everything else. Rod's "superdoor" should give you very similar performance, and for a fraction of the price of that professional door.

Any advice/suggestions are greatly appreciated. I'm building a 16x8x10 soundroom in Denver, CO looking for a little advice.

Those are lousy dimensions: your room is going to have serious modal response issues, since one of the dimensions (16) is exactly half of another dimension (8). The modes associated with those two dimensions are going to line up exactly, and reinforce. About the only way you could make that room worse, would be to make the other dimension also be 8'! You need to adjust at least one of those walls to get away form that bad ratio and closer to one of the good ratios. - Stuart -