Ready to complete my Basement Studio

Hello All, 2 years ago I built an addition with a walk out basement to my existing home. My intention was to someday build a basement studio. I plan to use the space to record local bands and solo artist including drums, bass, guitars, vocals. I have no nearby neighbors so isolation is not an issue. This is what I have to date in the basement.: Control room 15' X 13'8" X 8' on a floated floor. Live room 17' X 13'10" X 8' also on its own floated floor. I did also build a 2 X 6 dividing wall between the two rooms with drywall on both sides. All the exterior walls also have drywall and have been this way since I did the addition. I would now like to build a soffit wall on the north wall of control room with slot resonators on the west dividing wall and east exterior wall. My question is. If I frame a soffit wall like that in John's small studio sketchup will I be creating a third leaf? Do I need to remove the drywall from the existing exterior framing? I am including some pictures and a sketchup of my floor plan of my progress to date. I hope this helps to give a clear understanding of my question.

Hi Gonzo, and welcome! I'm a little curious about why you floated your floor like that, when you say that you don't need much isolation, and you probably had a great concrete slab under there to start with, since this is a basement. Putting a light weight leaf over a thin damped air cavity instead of just using the concrete floor doesn't seem like a good idea. You are also robbing yourself of several inches of room height like that. What resilient material did you use under the wood, to actually float it? Neoprene? EPDM? It isn't very visible in the photos. How did you calculate the load, deflection and area of the resilient material, that you needed for each pad? Also, what frequency did you tune that floor to? It seems like it would be pretty high, given then tiny air gap and lightweight OSB leaf. A couple of other things you said got my attention too:

I did also build a 2 X 6 dividing wall between the two rooms with drywall on both sides.

Is that done with staggered stud framing (2x4 studs with 2x6 plates), or plain ordinary 2x6 stud wall framing (2x6 studs with 2x6 plates)? From the photo it looks like ordinary 2x6 framing, and if that is the case, I'm wondering why you did it like that, instead of staggered? You won't get much isolation like that, since the leaves are not decoupled: there are many direct flanking paths between CR and LR. You could have gotten much better isolation between your rooms with staggered studs, or even better still, totally decoupled separate 2x4 frames.

All the exterior walls also have drywall and have been this way since I did the addition.

So you have a concrete block wall completely surrounding both rooms as the outer leaf, then 2x4 stud frames with a couple of layers of drywall on only one side of it, completely surrounding each room for the inner leaf (except for the wall between them which is a simple 2x6 wall)? Is that correct? Or do you have ANOTHER leaf of drywall in there too, in addition to the concrete block and inner-leaf that you show in the photos? What is the purpose of the styrofoam that can be seen in some of the photos? How come it is only on some of the outer-leaf walls, and not on others? Anyway, about your question:

I would now like to build a soffit wall on the north wall of control room

I guess you mean 30° splayed soffit panels across each of the front corners, for flush mounting your speakers? Is that correct?

If I frame a soffit wall like that in John's small studio sketchup will I be creating a third leaf?

No, since the soffit is part of the speaker, not part of the room. That sounds a bit confusing, I know, but basically the purpose of a speaker "soffit" is to act like an infinite extension of the front panel of the speaker itself, and is therefor also called an "infinite baffle". The entire soffit panel becomes the front of the speaker, basically, so in effect it is the thing that is radiating sound into the room, and therefore not really part of the room. So it isn't a third leaf: it is a speaker.

with slot resonators on the west dividing wall and east exterior wall.

The slot walls are also not really "third leaves", so don't sweat that either. One final question: Is it too late to fix the floor and the dividing wall? - Stuart -

Stuart, Thanks for your quick response. When I built my basement addition I had not stumbled upon this site. I actually built up my floor using a 1" hard rubber horse matt. I only installed this type of floor for climate control and to be able to install laminate flooring. I knew nothing nor still know anything about floating floors for studios. I have about 8'3" from floor to floor joist above. Is there a way to beef up the existing floor or will I be better off removing floated floor. My main concern would be trying to heat the floor in the winter if it was bare concrete. I would have to use some type of radiant heating and pour more concrete on top of existing. I would concider this if it was my only option. The dividing wall is standard 2 X 6 framing. Could I remove the drywall from the control room side, then build an additional wall at 12 degrees for the slot resonator? or does the slot resonator wall need to be sealed from dividing wall? This wall would not be an issue to rebuild with staggered studs. You are correct Stuart about the exterior walls Concrete Block, Styrofoam,2 X 4 Stud frame, Thermafiber sound absorbing insulation, 2 layers of drywall. The styrofoam is again for climate control. I did not want the block walls sweating and creating mildew on framing. Styrofoam is on all exterior walls. Again thanks for all your help, Gonzo

When I built my basement addition I had not stumbled upon this site. I actually built up my floor using a 1" hard rubber horse matt. I only installed this type of floor for climate control and to be able to install laminate flooring. I knew nothing nor still know anything about floating floors for studios.

OK, I hear what you are saying! This probably isn't going to very cheering for you, but here is a link to a thread that you probably should read, to help you get a better handle on the issues: viewtopic.php?f=2&t=8173 In fact, your floor most likely isn't actually floating at all, since the calculations were not done. So you basically have a bunch of coupled resonant cavities down there. I'm guessing that the floor is kind of a little bit "springy" when you walk on it? And you can probably hear your footsteps thumping a bit on the floor, as a kind of vague dull thud?

I have about 8'3" from floor to floor joist above.

OK, and you are going to lose a few inches there when you put up your inner-leaf ceiling (if it is built "normally", not "inside out"), so you could gain that back again from the floor, which isn't doing anything useful for you and is most likely working against you, both from the point of view of damaging your isolation and also acting like a drum head.

Is there a way to beef up the existing floor or will I be better off removing floated floor.

Others might not agree with me here (and I'm sure they'll chime in if they don't! :) ) but it might be better to take it up. The good news is that you can most likely re-use the materials, if you work carefully. Another option would be to lay dry sand, instead of the insulation, in the gaps between the joists, but that might not be worth your while. If it were my room, I think I'd bite the bullet, take up that floor, and lay proper laminate flooring directly on the concrete (with underlay, of course). Laminate floor looks good, is reasonably durable, very good acoustically, easy and fast to lay, not too expensive, and can be laid on top of a decent thermal underlay, to take care of your heating issues. But maybe someone else has a better idea.

The dividing wall is standard 2 X 6 framing. Could I remove the drywall from the control room side, then build an additional wall at 12 degrees for the slot resonator?

Not really, because.... :

... or does the slot resonator wall need to be sealed from dividing wall?

... correct! It needs to be sealed up against the inner leaf, in order to work. If you don't seal it, it wont work. It has to have an airtight back on it. You still have a couple of options, though, depending on how much isolation you need (you plan to track drums! :shock: , so you need lots :!: ), and how much effort you are prepared to put into it. The easiest option is to take off the drywall from one side, install resilient channel (or RSIC clips and hat channel) across the face of those studs, then put the drywall back again. That will gain you quite a bit of isolation, but will not maximize it. Another option is to take the drywall off one side and build a separate frame a little bit away from the first one, then put your drywall on the side of that new frame that faces the existing frame. In other words, build a new inner leaf "inside out", so that the studs are facing the room. And here you have the bonus of being able to use that structure for your slot wall! But that will take up extra inches that you might not be able to afford to waste. A third (and rather sad) option is to take down the entire wall, and build two separate 2x4 frames, each with drywall on only one side of it. This would be the most efficient in terms of isolation and space, since you would gain back those "lost" 2 inches, and it would also give you the option of splaying both your CR wall and your LR, even at different angles if you happen to want to. There are good reasons why you might want to do that. But before taking the decision on what to do, you might want to take a step back and analyze what you need in your build. Right now, you don't seem to have a firm plan in place that will give you the isolation and treatment that you need. You really should start out by defining how much isolation you need, then designing the walls, ceiling, floor, windows and doors to give you that amount of isolation. The entire structure, and everything in it, all work together as one large resonant system that has to be tuned to the right frequency and built to the right level, in order to give you the amount of isolation that you need. You said that you aren't concerned about bother neighbors, since they are a long way off, but that probably isn't your biggest isolation issue. I'm just guessing, but you probably need a lot of isolation between your live room and your control room, such that when you are tracking drums you will be able to hear the sound coming out of the speakers in your control room, rather than the sound coming trough the walls from the live room! If you want good drum recordings, you need to have good mic technique, and the best way of checking that is by listening critically to each mic in turn, in the CR, then adjusting it for the best spot. But if you can't clearly hear that mic by itself because there is too much bleed coming through the wall, then you'll never be able to do that well. So probably your limiting factor for isolation, is how much sound do you want to block between LR and CR. You might also have issues of disturbing other people in the house, or of things in the house disturbing your recording sessions: telephones ringing, people talking, vacuum cleaner, refrigerator, washer, dryer, water in pipes, toilet flushing, radio, TV, door bell, people walking around, pets, etc. There's a million things in a house that make a noise, and any of those would wreck your once-in-a-life-time perfect recording. So I'd suggest that you start out by setting some design parameters on just how much isolation you need, then looking at wall designs and construction methods that will get you there. You can do that by getting a sound level meter, checking out how loud you are going to be in that room, and how quite you need to be outside the room. And vice-versa. Subtract B from A. That will give you a number, which is how much isolation you need, in terms of decibels. Look over this forum for construction methods that will get you to that number, THEN figure out what that means in terms of how much of the existing structure you need to modify, and how much you can leave as is, or re-use. Yeah, it's sad to be in the position where you might have to undo some of what you did, but the god news is that you are not very far along yet, and you can probably make it so much better by backtracking a bit, and doing it right! But once again, that just my $0.02: maybe someone else has other ideas on what you can do with what you have. - Stuart -

Soundman2020 wrote:

"...but the god news is that you are not very far along yet, and you can probably make it so much better by backtracking a bit, and doing it right! -

The top of the newly framed walls are directly coupled to the bottom cord of the upper floor trusses which makes a flanking path both in and out of the rooms.

Stuart, I am taking your advice. I am going to design a plan to give me better isolation between rooms. Since my walls are flanking the floor joist, and sitting on top of the floating floor. I will start by removing the floor. I want to do this right. Gonzo

Great! That was a hard decision to take, I'll bet, but you'll be very glad you did, in the end. I'd suggest that you design your room completely in SketchUp, accurately and in reasonable detail, so that you can spot potential problems early on, while they are still in the form of bits and bytes, rather than in the form of real-world studs and drywall! - Stuart -

gonzo wrote:

Since my walls are flanking the floor joist, and sitting on top of the floating floor. I will start by removing the floor.

I would start by removing the framed walls ;)

I am attaching a sketchup plan of what the new rooms will look like. I will be using a 2 x 4, and a 2 X 6 wall for isolation between rooms. I will be removing the existing framing and flooring. The walls in red in sketchup are walls that need to stay. Aslo the Door opening on the 2X6 wall in red needs to stay. I decided to create a small storage closet to give me some isolation from the HVAC unit. If there are better suggestions for this area please let me know. I have tried to create a design that will give me a Control Room, Live/Drum room, and ISO/Vocal booth. with as much isolation between the rooms. Does this design look functional?

:D Started Demolition!!!. I am going to start with a clean slate. Removing walls back to block wall, and removing floor down to concrete. New walls will be built on concrete slab and decoupled from ceiling joist. First questions: 1. Would this type of subfloor work in a studio environment? A layer of 1 1/2 or 2-inch thick extruded polystyrene foam placed against the concrete, with a layer of 5/8-inch plywood on top. The whole thing is secured with Tapcon screws torqued directly into pre-drilled holes in the concrete floor. You get a warm, dry, all-wood subfloor.

here's one thought. see attached. another would be to flip this and have the air lock connect to the CR and live room with access to the isobooth via the live room. this would shrink the iso and live room and add a small storage closet. i'd open the HVAC into the air lock space either way.

Glen, great design. Unfortunately, the door for the HVAC unit needs to stay where it is in my floor plan that is where I change the filter from. Also, I am removing the existing wall that seperates the CR and the LR. So, anything goes as far as layout. I realy want to be able to track drums in my studio and need good isolation between CR and drum room. The only other isolation wood be from the floor above. Gonzo

so do you need an isolation booth at all? maybe the "airlock" space could be an extra isolation space and just go with a larger live room.

Demo 80% done!!!! Ordered Rod's book should be in early next week. Attached is my latest drawing using Glen's design. Question: If I plan on creating treatment walls along the perimeter walls. Do I need to apply a sheet of Drywall to the parimeter wall? If so, would this need to be done behind the soffit wall in the control room also?

Attachment will not load. My sketchup file is to large. Any clue on how to make the file size smaller?

remove unneeded materials and components and then purge the file using Model Info -> Statistics

I can not get my sketchup file smaller than 2.93 MB. Attaching a couple of JPEG's Question: If I plan on creating treatment walls along the perimeter walls. Do I need to apply a sheet of Drywall to the parimeter wall? If so, would this need to be done behind the soffit wall in the control room also?

What do you mean by "perimeter wall"? Are you referring to the outer leaf that surrounds all of your rooms? If so, those are concrete, right (or block, or something else like that)? You don't need to put any more mass on those walls. If they are concrete, brick, stone, block, or some such then they already have plenty of mass. Just make sure that you paint them with something that will seal up the porous surface. A couple of coats of paint will do the trick. It doesn't have to be fancy stuff, just something that is good at sealing whatever it is that your walls are made of.

I can not get my sketchup file smaller than 2.93 MB.

There's no way that what you are showing in there adds up to 3 MB. You probably have something very heavy on a hidden layer, or you might even have copied things on top of themselves, in the exact same place, or you have 3D text in there, or something like that. Are you sure you actually deleted everything that you don't need, then purged the file? - Stuart -

Stuart, I was talking about the 2X4 wall against the block wall. If I am going to build another treatment wall which will be inside out construction. is there and reason to put drywall on the 2X4 wall shown in last drawing?

I was talking about the 2X4 wall against the block wall.

Do you mean this frame? The one indicated by blue arrows, below? I'm not even sure why you have that there: it does not seem to be doing anything useful. Putting drywall on the outside of that (right up against the concrete) would be pointless, and putting drywall on the inside (facing towards the room) would leave such a small air gap as to compromise your isolation. And since they appear to be in direct contact with the outer leaf, you would have even worse isolation. Why is that frame there, anyway? Is it holding up something above it, that isn't shown on your diagram? I just don't see the reason for it. In any event, if that's the 2x4 framing you are referring to, then now, do not put drywall on that. Only put drywall on your inner-leaf framing. On that one, you can either do it normally, or inside out. I'm guessing that you are planning inside-out for there? It would make sense. On the other hand, re-reading your last couple of posts, I'm wondering if there is some confusion here. Is that 2x4 framing supposed to be your inner leaf? If so, then you have a problem: it is touching the outer leaf! Move it away from the outer leaf several inches, to give yourself enough depth in the air gap. - Stuart -

That is the framing wall I was talking about. It will be holding up the ceiling joist. You are correct Stuart, I am planning on putting up an inside-out treatment wall a couple of inches from that wall. Also, behind the block wall is earth and not much sound gets thru the wall. Would I still need to move the first 2X4 wall a couple of inches from the block wall? Joel

a couple of inches should be fine.

Almost ready to start building. I am still unclear on which wall is to be my inner leaf? I have an 8" block wall which is my outer leaf correct? outside of this block wall is earth, I am building in a basement. Do I need to build an inner leaf wall with a 2" air gap from the block wall as shown in the attached sketchup file? Looking at the design that John did for Javier The drywall is on the side of the exterior wall. Is the drywall on my drawing on the wrong side of the inner leaf?

the 2x4 running next to the exterior walls would be the inner leaf and you would leave a couple of inches between the exterior wall and the framed wall. remember that 2x layers of 5/8" drywall is about 1 1/4" so calculate the distance based on 2" between the outside of the drywall and the exterior wall. on the inside of the new inside-out wall, fill in the joists with your rockwool insulation to dampen the resonances. the angled framing is then your treatment walls which will contain the various bits: bass traps, slat resonators, porous absorption, etc.

I have an 8" block wall which is my outer leaf correct? outside of this block wall is earth, I am building in a basement. Do I need to build an inner leaf wall with a 2" air gap from the block wall as shown in the attached sketchup file?

Yes and no! :) Don't you just love those clear, accurate, unambiguous answers? :) No, you probably don't need to do it, assuming that your basement is entirely underground, all the way up to above the top.... provided that the ceiling is the the same: 8" of concrete with earth on top. Of course, it isn't. The issue is that in order to isolate upwards through the ceiling, you also have to isolate the walls. It has to be the same all around, unfortunately. If you don't build those side walls, then you have no way of building your ceiling as an MSM structure. So the walls do have to be there, and they do have to have roughly the same level of isolation as you need on the ceiling. So in reality you don't

need

to do it, but you still

have

to do it if you want food isolation. Just do it like Glenn said, and you'll be fine.

The drywall is on the side of the exterior wall. Is the drywall on my drawing on the wrong side of the inner leaf?

It is neither "wrong" nor "right"! (Again! Totally unambiguous answer!) There are two ways you can build your wall. You can put the drywall on the side that faces the cavity, or you can out it on the side that faces the room. The first method is called "inside-out" construction, and the second is called "normal" construction. Both ways work. Both have pros and cons.... (The method Glenn describes above is the inside-out one). - Stuart -