New Build - Project Studio in Raleigh, North Carolina

Hi, My name is Don. I have been recording and mixing for the last few years as a hobby. I am planning on retiring in the next year or so and want to spend my time concentrating on music. I have a tremendously supportive wife who has suggested I build a small studio on our property. Or maybe she just wants me out of the house?? :? I am very early in the process but have spent a LOT of hours reading this and other forums and a couple of books (Rod Gervais, Philip Newell). Unfortunately we live fairly close to neighbors. The studio would be about 40 feet from the property line and about 70 feet from the neighbor's house. But - I'm getting ahead of myself... I have been looking at many of the designs on this website and have found a few that look like they would meet my needs. But the designs have led to some basic questions. One design I was looking at was the one labeled "Layout 10-1" in "Nashville Studio Build" at http://www.johnlsayers.com/phpBB2/viewtopic.php?f=1&t=17481&hilit=nashville&start=30. (I'm not sure how to post the jpg here.) The design makes use of soffit mounted monitors. I have the Barefoot MM27's so I think that rules out soffit mounting. In general what would I need to do to modify a design that uses soffit mounted to speakers for use with the MM27's? Can I just eliminate the soffit? Do I need to replace it with an sound absorber of some sort. I figure I need to at least have an idea about the requirements for the MM27 placement to start putting together a Sketchup plan and ask some specific questions. Thanks for your help. Don

Hi Don, and Welcome! :)

In general what would I need to do to modify a design that uses soffit mounted to speakers for use with the MM27's? Can I just eliminate the soffit?

Yes you can! That will have some acoustic consequences, of course, but other aspects of the treatment can be changed. That said, the specific design you referred to ("10.1") was modified in several ways later in that thread, and eventually discarded in favor of a better design, so that might not be such a a good option for you.

Do I need to replace it with an sound absorber of some sort.

Yes. If you remove the soffits, you will have a bare wall behind the speakers, which means that all of the artifacts that the soffit was eliminating will now be back in the room, so you'll need to treat them in other ways. Absorption on the front wall is a good way of dealing with first reflections, SBIR and comb filtering, for example.

I figure I need to at least have an idea about the requirements for the MM27 placement to start putting together a Sketchup plan and ask some specific questions.

You could ask Barefoot himself what he recommends, once you have your basic plan laid out. He posts here occasionally (although I haven't seem him around in a while), so maybe you could PM him, or e-mail him at his own web site. - Stuart -

Thanks Stuart. I have done a bunch of reading and thinking about how I would actually utilize the space. I will be using it for recording small to medium sized groups. One of the groups is an 8 person Acapella group (who all want to be in the control room to listen to tracks. Most are 3 to 6 person pop, rock, country-folk groups. And a large part of the time it will just be me and a few friends - probably more convenient to use the control room for this. So my current thinking is a medium sized control room (capable of handling 9 acapella singers) that I can use for recording and playing with friends. A separate space that can be used for recording drums, small groups or a loud guitar amp. There is also a small bathroom. This is new construction and will have a 3 car garage in the front of the building. I would like to keep the ceilings high (10-12'). It will be built on a concrete pad. This is a residential area and the neighbors are close and I need to keep the noise to a minimum even when recording drums. I'm thinking I probably need to get 65-70db sound isolation. I am attaching a Sketchup file of the initial attempt at a design. Is that the easiest way to post these early attempts or should I just post a jpg? I haven't added proper doors yet. The two doors on the left lead to an enclosed walkway to the house. I want to avoid any actual physical connection to the house. My wife is EXTREMELY adverse to noise/music. I think that is why see suggested building the studio in the first place. As others have said so many times...This web site is an incredible resource. I have read a lot of the threads over the past several months and have read most of Rod's Home Recording Studio, and quite a bit of Everett's Master Handbook of Acoustics. The books have been great but the information shared on this forum is truly incredible. I really appreciate any comments and suggestions you may have. Some immediate questions: - Should I have two leaf walls around the entire 33'x33' area including the bathroom and hallway? - Do you think the control room will work for mixing and recording in the same space? Would I make the monitor end very dead and put diffusion on the sofa end? I thought about making the whole space dead and throw up a couple of room mics and run it through my Bricasti at low levels through the Barefoot MM27's for a more pleasant room sound to jam with friends in the Control Room space. - Anything with the plan that looks half baked? Thanks!!! Don

Slight modification to the previous plan. I hope someone will comment soon. I know there are probably a lot of things that I am not considering. This whole thing is more than a little intimidating. Don

I am attaching a Sketchup file of the initial attempt at a design. Is that the easiest way to post these early attempts or should I just post a jpg?

Posting the SKP is good, and also adding a jpg or two is better, as it makes it easier to get an idea with just a glance at your thread, without downloading and opening the SKP.

- Should I have two leaf walls around the entire 33'x33' area including the bathroom and hallway?

Not necessary, since they will be "outside" the actual isolated area of the studio.

- Do you think the control room will work for mixing and recording in the same space?

It should work, yes, but you seem to be wasting space by splaying the entire length of the left and right walls. You only really need to splay the front part, up to the mix position, and the splay angle should be larger, if you hope to achieve a true RFZ.

Would I make the monitor end very dead and put diffusion on the sofa end?

Not necessarily. Furniture upholstery is often made from closed-cell, which does not have much in the way of useful acoustic properties, and even if it does have open-cell foam in it, then you would just need to take that into account when you determine the total amount and placement of room absorption. There are equations that tell you how much absorption you need in the room to get the RT-60 times under control, and the general rule is to spread it around evenly for maximum effect, so as long as you take that into account, you should be OK.

I thought about making the whole space dead and throw up a couple of room mics and run it through my Bricasti at low levels through the Barefoot MM27's for a more pleasant room sound to jam with friends in the Control Room space.

Dear rooms are unpleasant to work in, and trying to fix that artificially is a "kludge" the will only work for some places in the room at any given time. Not a good idea. It is far better to get the room itself sounding good, smooth, even and neutral by appropriate design and placement of treatment. - Stuart -

Thanks for your help so far Stuart. I have been silent for a while but still plan on moving forward with building a project studio. We are also doing some house changes at the same time so we have been focusing on them lately. We have the house plan pretty much resolved and I need to get back to studio design. There will be a 3-car garage at the front of the studio building. So the width is 33'. the depth is somewhat flexible. Shooting for around 30-33'. After reading books and forums and confusing myself with possibilities I have pretty much decided that the plan that "Shybird" came up with for his Nashville studio - Layout 14.5 (viewtopic.php?f=1&t=17481&start=105) is almost perfect. I have started discussions with a contractor. He hasn't built a studio before but he does great work on residential and commercial projects. And he seems to be very flexible and willing to do whatever we need him to do. Since this is a new building we are starting with a blank page. It looks like I need to shoot for 70db of isolation. A little more wouldn't hurt but 70 would work. It will be on a concrete pad. Now for the initial questions that I'm hoping someone can help with. - Does the pad need to be poured so that the live/control room floors don't extend to the exterior walls. Or is there enough TL to get 70db reduction with one big pad? Or do we isolate the interior rooms from one another but leave the pad for the exterior walls coupled to the interior space? I am concerned that having a separate pad for just the exterior walls may not provide enough support. We have had settling problems in the house foundation. - What do I need for walls for 70db TL to the exterior? I was thinking about sand filled cement block for the exterior wall but that might be overkill. Does a cement block filled with sand constitute one or two leafs. If the chamber in the block makes it act as two leafs how do we avoid a triple leaf problem with the interior walls? Are we better off with a wood frame with Hardiplank siding? Thanks, Don

Good to hear that things are moving forward, Don! I was kind of wondering what had happened...

I have pretty much decided that the plan that "Shybird" came up with for his Nashville studio - Layout 14.5 is almost perfect.

It's a pretty good layout, I think. He spent a lot of time refining that.

I have started discussions with a contractor. He hasn't built a studio before but he does great work on residential and commercial projects. And he seems to be very flexible and willing to do whatever we need him to do.

I would suggest that you ask him to read Rod's book before he starts on the studio section. That will give him the basis for what he needs to do different. And considering the very high level of isolation you are after, it is critical that he do everything perfectly.

It looks like I need to shoot for 70db of isolation. A little more wouldn't hurt but 70 would work.

About that... 70 dB is do-able, but it is not easy to get there. It's a pretty tall order, actually. Not to discourage you! Just to point out that this is going to require some very careful design, very careful attention to detail in the construction, especially in the doors, windows and HVAC system. If you take a close look at IR-761, out of a total of over 300 techniques for building isolation walls, you'll see that there is only one single construction technique that gets to STC-69, one more at STC-67, and two at 66. The vast majority are below 60. And that's STC, not even true transmission loss. So that should give you some clarity on what you are trying to do: it can be done, but isn't easy.

- Does the pad need to be poured so that the live/control room floors don't extend to the exterior walls.

For your level of isolation, I would pour separate, isolated slabs for each room, in addition to the actual outer-leaf foundations for the building itself. So there would be one slab (with integral footings), for the live room, one slab (ditto) for the control room, and the outer-leaf walls plus the rest of the building would be on a third set of footings/slab.

Or do we isolate the interior rooms from one another but leave the pad for the exterior walls coupled to the interior space?

I think the last part of that sentence should have read: "... exterior walls coupled to the exterior space". (not "interior". If you have separate slabs for the inner rooms, then your exterior walls, by definition, are not connect to the interior space. There's only two sets of walls here: the "outer-leaf" which surrounds the entire studio area and is connected to the rest of the house, and the "inner-leaf" walls of each room.

I am concerned that having a separate pad for just the exterior walls may not provide enough support. We have had settling problems in the house foundation.

Well, each slab needs it's own foundations, obviously, and if there is any question of settling, then you should get an engineer to look at at that, and design your footings/foundations/slabs accordingly. You may need to have concrete pillars going down to bedrock...

- What do I need for walls for 70db TL to the exterior?

If you are going for 70 dB of isolation to the outside world, then you might as well do it between rooms as well.

I was thinking about sand filled cement block for the exterior wall but that might be overkill.

Definitely not overkill, if you want 70 dB of isolation! According to BRN-217, if those were 4 inch solid concrete bricks (not solid) you should be getting around 45-50 dB of isolation from that. Mass law predicts around 55, but I'd go with BRN-217, since those are actual real-world laboratory tests. For hollow 6" concrete block, the story is about the same. 8" block is a fraction better. So that basic construction will give you roughly 45 dB of isolation to start with. The sand will add a little to that, maybe 2 or 3 dB. So now you need to add another 25 dB to that, to hit your target. That's where things get a bit more complicated... :)

Does a cement block filled with sand constitute one or two leafs.

One leaf.

Are we better off with a wood frame with Hardiplank siding?

I would not go that way. Your basic plan so far is going in the right direction. Outer leaf: sand-filled concrete block for the walls, and concrete slabs for the floor and the ceiling. I would then render all that with plaster on both sides: that should add about 5 dB, according to BRN-217. Then I would put up 2x4 24"OC stud framed walls for the inner-leaf, using at least an 8" air gap, filled with 30kg/m3 fiberglass wool, then at least two layers of 5/8" drywall (maybe 3 layers) on only one side of the studs, and Green Glue in between the layers. In theory, that should get you close to 70 dB. But like I said before: the biggest issue for such a high level of isolation will be the doors, windows, and above all the HVAC design. Those are going to be a real challenge... - Stuart -

Thanks Stuart. That was a bit scary. Especially the "Outer leaf: sand-filled concrete block for the walls, and concrete slabs for the floor and the ceiling" part. A concrete slab ceiling sounds very expensive. My wife and I are reviewing the entire house/studio plan to see if I can get the studio somewhere else on our lot that would be further from the neighbor's house. Then we wouldn't need as much isolation. Or I just don't allow drums at night. Or any other LOUD activity. I guess we have some decisions to make before I continue. Don