John Sayers' Recording Studio Design Forum

I am planning to build a control room in the basement and eventually build a live room next to it. The basement has a concrete floor with poured concrete walls. Ceiling is floor joists plywood then carpet on top. I plan to build a single walled room. Because I am renting I can't go too crazy with it. The room will mostly be used to mix projects anytime of the day. I tend to mix at late hours of the night so isolation is a must. I was thinking of doing double 5/8" drywall on the inside, 2x4 frame with insulation and single 5/8" on the outside. That will give me 2 leafs. I know it would be better to build two different walls and space them, but I don't have the space or money to go to that extent. I think as long as I don't let the new room touch any of the basement walls or ceiling I should be able to get some decent isolation with this plan. Ceiling height when finished is going to be just shy of 7' (I know a low ceiling) , but it's what I have to work with. Dimension will roughly be 11'x17'x7'. Does this seem like a decent size and shape? I am trying to work off of the 1: 1.6: 2.33 ratio. I think I get how the modal calculators work and it seems to look good when I plug these numbers into it, but I am not completely sure. Still a little confused on what I should be looking for there. On the side of where the room would be built is a water line that sticks down from the ceiling, (can see it in the picture) so I have made splayed walls towards the back of the room to work around that. Is this a good idea? I am also a little concerned if 2x4's spaced 16" running 11' from wall to wall for the ceiling is going to be strong enough to hold 3 layers of 5/8" drywall. When it all comes down to it I am trying to achieve a room that I can mix in at anytime of the day. My roommates bedroom is located upstairs almost over the studio, and we share a small concrete wall in the basement by the washer and dryer with our neighbors. I would love any suggestions on how to make this build the most effective with what I have to work with. Thank you!

Hi "aseymer", and welcome!

Actually, that would give you THREE leaves: the existing concrete walls and plywood ceiling, plus the two new leaves you would be adding.

It may be possible to gain a couple of inches on that: What is the height to the bottom of the joists right now?



Your actual ratio would be 1 : 1.57 : 2.42 with those dimensions. Your target ratio comes in at #22 on the list prepared by Eric Desart and used by Bob Golds for his calculator. You seem to have enough space to be able to do better than that. Is there any reason why you don't want to aim for abetter ratio? I didn't try any other combinations, so I suspect that ceiling height might be the problem, but as I mentioned above, you might be able to squeeze out an extra couple of inches still...

Splaying the walls is useful acoustically, and it looks like you are heading in the right direction for an RFZ design, so yes, that is a good idea. Except for one thing: You have the room oriented backwards! If you splay the walls, then the narrowest part of the room must be at the FRONT, where the speakers are, and the room should only get wider as you go backwards. So you should flip your internal layout 180° and move the door to a more suitable position.

According to common span tables, depending on the type of wood, you'd need at least 2x6 for that type of load at that span, it seems. Maybe more.

I would suggest that you fix your three-leaf design first: Since you are only using a portion of the basement, you need to close of the other two sides in that basement corner, to complete the outer leaf. The two concrete walls in that corner already form two sides of your outer leaf, so you just need to build two more walls to complete the enclosure, inside which you will then build the actual studio. Those two new outer-leaf walls can just be simple 2x4 stud frames, floor to ceiling, with a couple of layers of drywall on just ONE side, probably the side facing the rest of the basement (so the studs will face the area where the studio will go). If you need a high level of isolation, you should also "beef up" that subfloor above that section with more mass, such as by cutting strips of drywall to fit between the joists, held in position with cleats, then sealed around the edges with acoustic caulk.

With the outer leaf complete, you can now build your inner-leaf, which once again consists of a single stud frame with a couple of layers of drywall on only one side. The gap between the two leaves should be filled with insulation. There are a couple of techniques open to you for the inner-leaf ceiling, and a couple of photos of what is up there tight now would help to settle on one of those.

The other thing that would help to settle on the design, is the answer to the question "How much isolation do you need?". In objective terms of decibels. You say that this is just a control room, where you only need to mix: no tracking will take place. That simplifies matters somewhat, and makes me think you are over-designing the room. If this is just for mixing, and assuming you mix at standard levels with occasional "peaks" to check the low end, then three layers of 5/8" seems like overkill. Two layers would probably be more than enough, and you might even be able to get away with just one layer, if done very carefully.

If done correctly, then you could actually save both space and money, and in addition you would end up with much better isolation.

The other suggestion I would make is to soffit-mount your speakers. You seem to have the space to do that, and your current drawing shows the speakers in almost the right position for that, so it certainly is worth thinking about. What speakers do you plan to use in this room?


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

First of all I would just like to say thank you for responding so fast, and this forum is a blessing to all of us on here in need of guidance. Thank you!



For some reason I thought that since the basement itself is not sealed air tight that this would not technically really be a 3 leaf design. I am renting the house and I agreed not screw into anything already existing. So that is why I am only doing a single frame wall. Should I just do 2 layers of 5/8 on the inside of my frame, then insulation on the outside?



Lowest point to the bottom of the joists is 88". There is ducting running in between the joists, and electrical conduit running right under the joists as well. Therefore this will not let me be able to tuck my new ceiling joists that I will be building between them.



Sorry... I guess I should have been more specific. Dimensions will be 16' 4" x 11' 2" x 6' 11 3/4". So if I'm not mistaken this should give me a 1 : 1.6 : 2.33 ratio which comes in at #4 on the list? http://forum.studiotips.com/viewtopic.p ... d1ce4#5570



ok I noticed a trend on here that that's what people tend to do. What are the advantages of doing it this way?



What do you think the max drywall amount I could get away with by using 2x4's for the joists? Is there a certain way I can brace it to support more weight by using only 2x4's?



Once again I am renting and I agreed to not build into existing structure. So this leaves me with the question, What is the best way to build this single frame wall so that when my roommate is sleeping upstairs he will not be disturbed? Do you think this will be possible with a single frame room, 2 layers 5/8's on the inside and insulation on the outside? I am pretty confident that I will not disturb our neighbors mixing at night with this plan but am concerned about roommates bedroom almost directly above me.



Most likely I am going to stick to monitors on stands. The speakers I will be using are KRK RP6 G2.

Here are some pictures of what I have to work with.

Thanks again!

looking down the room


left side of room


Right corner


The conduit above room


Water pipe toward back of room

Can anyone help?

It doesn't have to be air-tight to be three-leaf. Just the simple fact of having a leaf close by, even if it is just a sheet of plywood held up in the air, is still going to be three-leaf.

However, if you have a large enough air space between the existing walls and the new room, then you should be OK.

Pity! Since it is a rented space, then I guess moving those ducts and conduits is probably not possible?

Have you considered building your ceiling inside-out, to help gain back a bit of space inside the room?

The trend for RFZ, or the trend for rooms being wider at that back? Having the room widen out helps acoustically in several ways, starting with acoustic loading of the speakers by the room, but also including reflections and even aesthetics. RFZ is a subject all by itself, but the benefits are simply that the engineer hears only pure, clean, direct sound from the speakers, with no first-order reflections to muddy things up. Combine that with soffit-mounting for the speakers (flush mounting) and you also eliminate a number of other issues, improving things even further.

You can reduce the spacing from 16"OC to 12"OC, and you can use tougher wood for your joists, but you really should check with a structural engineer for advice on what is safe and meets code in your area.

I would suggest moving the room as far away from the existing building walls as possible, putting two layers of 5/8" on each side of the studs, but using resilient channel (or isolation clips plus hat channel) on the inside. That will give you the best of both worlds, with pretty decent isolation. Of course, you also need to put insulation in BOTH cavities: the one between the leaves in teh new wall, and also between that and the existing walls: You do need the damping there.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

ok. I think I may actually just use use 4x4" for the ceiling since keeping as much vertical height is an issue, and that should give me a lot more support instead of using 2x4".



Because of low hanging pipes and ducting in other areas of the basement I pretty much have to keep the structure exactly where I originally had it. If I were to drywall both sides of the frame the outer leaf of 2 walls and the ceiling would be roughly about 10" from from the existing walls and ceiling in the basement. Would it better for me to do drywall only on one side (inside) with RC, on these 3 leaf prone areas, and drywall both sides on the exposed walls, or just do the inside with resilient channel, or would doing both sides of the frame all the way around with resilient channel on the inside be ok, or stick to what you originally said given my 10" space from existing concrete basement walls? I'm sorry if that was very confusing, but I don't know how else to put it.

If I end up doing both sides of the frame with drywall, what is the easiest way of attaching it to the outer side of the frame since it will only be 10" away from 2 of the existing walls?

Thanks again for your help Stuart!

I'd say that your only real option is to live with the minor 3-leaf problem, and just do the whole booth with drywall directly nailed/screwed to the outside of the studs, and on resilient channel on the inside. So your booth will be two-leaf all around, with drywall inside and out on all four walls plus the ceiling, but using RC-1 on the inside to decouple the drywall from the studs.

You'll still have that 3-leaf issue, but on only two sides of the booth, and those two are thick concrete walls damped by earth on the other side, so you should be just fine.


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.