It's Time to Start My Basement Studio

Hi everyone. My name is Bill Childers and I live in a small town in North Carolina US named Marion. I have been reading this forum for quite some time an I think I am ready to dive in and seek the professional assistance of the engineers and designers on this forum for my basement studio. Location: The location is in a rural area with neighbors on both sides but they are at least 100' away. No neighbors if the front or behind. Space: The current basement exterior walls are insulated and are 6" thick. The floor is concrete and the wall height is 100". The ceiling in the basement is a finished drywall attached to floor trusses to the upstairs (no insulation between the basement ceiling and the upstairs floor). Yes I said floor trusses so I have unique situation in that the basement is open with no post. There is also an electrical panel on the wall in the studio layout area. Budget: 15,000 - 25,000 USD I am attaching a .skp file of the area as it is now. You will see that I show a stud wall in the drawing but it is not there. It is to show the area that I have available to use. I would like a control room, live room and two ISO rooms if I can. Thanks in advance for all the help and I look forward to completing this with the help of this forum. Bill Childers

I moved the wall so the electrical panel is no longer in the studio area

Hi Bill, and Welcome!!! Could you tell us a little more about what you plan to do in there? For example, is this a commercial facility, or just a hobby studio? What type of music do you record? How loud are you, and how much isolation do you need? (I know you said that disturbing your neighbors is probably not a problem due the the distances, but you still need isolation between CR, LR and booths, and also between the studio and the rest of the house, so that is what will define your construction method). - Stuart -

Stuart, Hello and thanks for your response. I will try to answer the questions to the best of my ability. This will be a commercial facility as I have been doing it as a hobby for a couple of years and have begun to build a client base. They type of music is southern gospel, contemporary, country and bluegrass so the instrument types will vary greatly with the style of music. The instruments will include drums, acoustic guitars, electric guitars, steel guitars, piano and wind instruments so it is possible for the sound levels to be pretty great. Isolation between the living quarters upstairs and the recording studio downstairs I would like to minimize as much as possible but I know there may be a limit as to keep my ceiling height. Hope this answers the questions. Bill

So Bill...isolation is going to be of great importance since you guys in the hills do acoustic recording. I can get you a typical isolation design for the framing in a few hours/day but I have to ask a few more questions. You are willing to remove the existing sheetrock on the ceiling and add additional mass to the upper, bottom side of the floor yes? You did not give an dimensions of this area...what will they be? "The current basement exterior walls are insulated and are 6" thick. " What does that mean? What is the construction materials...partial block with 2 X6 knee walls above grade...exterior siding/interior sheetrock...what? Do you have any pictures of this room/space?

Hi and thanks for your response. I will try and answer the questions. Q - "You are willing to remove the existing sheetrock on the ceiling and add additional mass to the upper, bottom side of the floor yes?" A - I can add mass to the bottom which is the ceiling in the basement. I cannot add mass to the upper because that is the living space. Q - "You did not give an dimensions of this area...what will they be?" A - The studio area is 22' 4"x 30' 10" Q - "The current basement exterior walls are insulated and are 6" thick. " A - The exterior wall are 2"x6" studs, insulated, 16" OC, 1/2" OSB exterior sheeting, vinyl siding on the wall where the electrical box is located and the adjecent wall, the third exterior wall has a stone siding. 1/2" sheetrock on the interior walls. Q - "Do you have any pictures of this room/space?" A - Adding them now

"I would like a control room, live room and two ISO rooms if I can" This is where it gets interesting. To get this type of controlled environment with high levels of isolation between room, you'll have to consider a few thangs :) Main component in this scenario is the ceiling. If you are wiling to construct a room in a room type environment then the ceiling is not an after thought but has to be included in this aspect. So if I can guess @ your floor/ceiling I would say it has an stc of 50 ish -/+ with the impact from above and flanking mostly reducing it to less than that. Not too good for want of isolation in a home that will have a tv/radio/teenagers/friends, etc upstairs making all manner of noise trying to get on your digital recording. And this is only one place. If you are willing to do this as well to your existing walls (remove the existing sheathing, mass up the exterior of the frame and build interior framing with mass) then you can get a good place to record. To what extent you are willing to go is the question...what level of isolation you require and how much you are willing to endure to get there.

Brien, Thanks for the response. Demo of the ceiling is a last resort if possible but not totally out of the question. I have several types of buiding material available to myself. Example: Shotty material: (this is used in the automotive industry for the backing if automobile carpet and for sound isolation in other areas of the car.) I have friends that work their and I can purchase those materials if needed. I can get variable thicknesses from .25" to 2". Rubber products: (neoprene including gums and material reinforced, etc.) I am an electrical engineer in the rubber industry so these products are available to me also. Those were my initial thoughts to build rooms inside of this area including a ceiling for each room. Could you give me you ideas as to the layout considering the windows, ceiling, and height? Regards, Bill

Bill, Building materials are fine but the principles involved in constructing an isolated environment are difficult to modify. With a one room space you can do different things, but with multiple rooms you run the risk of flanking and bleed from the absence of a true decoupled environment. This ceiling overhead...when you stand in that room do you hear noise from above...impact (folks walking) TV (airborne/flanking) of anything that concerns you? Adding more mass to the ceiling, as is, can reduce some of this. The issue you will have is that with multiple rooms this sound penetration will inhabit every room...since there will be no separation from one to the other in the ceiling and flanking/direct sound is going to be an issue. That said, you can do what you want with the walls but the ceiling is your weak area, and has to be developed further, or you spend money that is better placed on other things. I appreciate what the automobile industry does. But what they do is for vehicles...not for a wooden structure. So any attempt to damp something using an asphalt based product in a residential environment introduces several obstacles. The first is a fire hazard...and your home insurance carrier will address that better than I can. But to the end of isolation or as an acoustic device these products may well fail you in what you think you can achieve with them. The deflection of this overhead floor is going to come into question in any event.

Brien, I may be way off on this but if I add another layer of 5/8" sheetrock to the existing ceiling in the basement then build each of the studio rooms, including a new decoupled ceiling for the studio, would this then not give me a pretty good isolation from the rest of the house? I just remembered :idea: also that the HVAC duct is enclosed within the truss system and so I cannot add new ceiling joist between the floor trusses. Regards, Bill

billcsec wrote:

Brien, I may be way off on this but if I add another layer of 5/8" sheetrock to the existing ceiling in the basement then build each of the studio rooms, including a new decoupled ceiling for the studio, would this then not give me a pretty good isolation from the rest of the house? I just remembered :idea: also that the HVAC duct is enclosed within the truss system and so I cannot add new ceiling joist between the floor trusses. Regards, Bill

What it will do is subtract from your overall head room, then the undamped joist cavities will allow whatever impact noise from the upstairs/flanking to migrate directly into your room(s). Then the hvac that is designed for a "house" still has to be modified. That is at least three reasons why you should look into changing this design. Oops....there is a fourth. the existing coupled assembly (a hard boundary on one side, the framing and another hard boundary on the opposite side) often mislabeled as a double leaf, more correctly labeled a two sided coupled assembly, with the added hard boundary, decoupled or not, will reduce the isolation, or rather the assemblies ability to stop sound and will be reduced further again by the inherent flanking. Since we do not know your isolation profile yet, I have to ask...what is it you are expecting in this build when it comes to noise traveling from the room below to the room above and vice versa? The doubling of mass on the existing ceiling will gain you some extra points in isolation, but it did not change the flanking, the impact from above and we still have to address the complete modifications of air in/air out of these rooms to eliminate the potential for a sound bridge in your existing hvac system. Which btw, is designed to pull return air from the over all room...when you build walls and enclose spaces and install sealed doors, this hvac return doesn't work like it used to and the system is burdened. Your existing floor I-joists or engineered joist with a 5/8 OSB sub-floor and underneath 5/8" sheetrock are getting you in the neighborhood of 48-52 on the STC rating. If you double the mass on the ceiling with another 5/8" layer of rock, all things considered, you may get another 5 points. Adding a lightweight concrete topping to the above floor surface may get you another 4-5 points...there again, all things pending. But an acoustically correct structure while being the road less traveled and always cost more than you would have thought...yields numbers in the area of 70+ as an assembly. Like I said, you can make the floor marginally better, but as soon as one of those walls gets attached directly back to the existing framing...you lose. And then there is the rigidity that you add to the existing floor assembly if you should choose to frame directly beneath it...that's a hard path that you will hate yourself for discovering.

Bill, you say this is going to be a commercial studio, and that you will be recording everything from vocals to drums. You say you don't need too much isolation going out, but you might need a fair amount for sound coming in: I'm assuming that there will be other people moving around the house while you are recording, so you could potentially have noises like phones ringing, TV, radio, vacuum cleaners, walking, talking, cars, dogs, lawnmowers, water running, toilets flushing, etc. You might also have other noises that you hadn't considered, such as wind, rain, thunder, aircraft flying over, etc. Any of those noises could ruin your very best ever once-in-a-lifetime perfect solo, so I'd really suggest that you might want to re-think your isolation requirements. In fact, it would be good to put some real numbers to these ideas. Do you have a sound level meter? If not, then beg, borrow, or buy one. They aren't expensive (you can get them for around US$ 50 - 100 on e-bay), and they are a very necessary tool. Once you have one, let me know so I can guide you through a couple of things to put real numbers to important questions like "How loud are you?" and "How quite do you need to be?", and "How loud is the ambient level, best case and worse case?". Etc. The reason why we need numbers is because there are different ways of attacking the problem of isolation, and each one will give you a certain amount of isolation. So once we have your numbers, we can figure out which is the most cost-effective method for you to get to the number that you need.

A - The studio area is 22' 4"x 30' 10"

And the height? You said the wall height is 100", so I'm assuming that's where the ceiling is, and that it stays at that height all across the room?

A - I can add mass to the bottom which is the ceiling in the basement. I cannot add mass to the upper because that is the living space.

Well, you CAN add mass to the subfloor, but not the way you are thinking now: If you take the drywall of the ceiling of your room, then you will be looking at the subfloor from below. And you can add mass from below as well. This is a common method of improving isolation, and is generally referred to as "beefing up", around here. You do it by cutting pieces of 5/8" drywall to the exact size and shape of the areas between the joists, and fit them in carefully, sealing around the edges with caulk. Generally one or two layers is plenty, but you do have to check that you will not be overloading the floor with all that extra mass. A structural engineer can tell you about that.

I may be way off on this but if I add another layer of 5/8" sheetrock to the existing ceiling in the basement then build each of the studio rooms, including a new decoupled ceiling for the studio, would this then not give me a pretty good isolation from the rest of the house?

Unfortunately, not. There is the issue of the dreaded evil "three leaf" structure. Contrary to what common sense tells you, if you have a wall or ceiling with two "leaves" on it (lets say an ordinary 2x4 stud wall with drywall on each side: the drywall is the leaves), and you add another leaf a short distance away, your isolation can actually get WORSE at some frequencies in the low end of the spectrum, not better. That isn't intuitive at first glance, but that's the sad truth. The reason is simply that most people don't realize that when you have two "leaves" of mass like that, with air trapped between, then you actually have a tuned system. It's a basic principle of physics, called "MSM" for "mass-spring-mass". All MSM systems have a natural resonant frequency. In the case of that wall, the MSM resonance defines how well the wall isolates. In fact, the wall actually amplifies sound passing through it at the resonant frequency, and only isolates well at frequencies beyond twice the resonance. If you add another leaf a short distance away, you now have an MSMSM system, (mass-spring-mass-spring-mass), and the resonant frequency will be much higher than it was. In effect, you have re-tuned the wall! So even though you added more mass to it, you also changed its resonant characteristics. Most likely what you have done is to move the resonant frequency up into the mid range, which means that things that were not audible through the wall before, are now perfectly audible. It's a bit more complex than that, but the sad reality is that three-leaf and four-leaf structures are generally a bad idea, as you might end up making matters worse than the already are. That's my rather long and convoluted way of saying: Don't build 3-leaf. :) That said, sometimes you just have to build 3-leaf things, and there are ways to compensate for the effect, but it simply adds more expense and more complexity.

I just remembered :idea: also that the HVAC duct is enclosed within the truss system and so I cannot add new ceiling joist between the floor trusses.

You might not need to! :) I'd suggest that your plan of action should be to get out your sound level meter, do some tests to see where you are with isolation, and where you need to go, then we can decide on what you need to do in order to accomplish that. - Stuart -

Soundman2020 wrote:

I just remembered :idea: also that the HVAC duct is enclosed within the truss system and so I cannot add new ceiling joist between the floor trusses.

You might not need to! :) -

Yes he will.

Yes he will.

Not if he builds inside-out ... :) - Stuart -

I thought I would add a couple of pictures of the sketchup file to show what I am talking about Bill

Bill, if that's all you have up there (one central HVAC duct) and you lay out your rooms right, you actually might have space to interleave joists between your trusses. But once again, if you build your ceiling inside-out, then you don't need to. - Stuart -

Stuart, Whew! Thanks I would rather not tear out that ceiling. I will look at other post about the inside out ceiling but could you please explain it here and help me with progressing with my design? Regards, Bill

Whew! Thanks I would rather not tear out that ceiling.

I think you misunderstood what I was saying, Bill: I don't see much option about taking off the existing drywall, for the reason I outline about triple-leaf isolation. It's pretty much a foregone conclusion that you'll have to do that, if you want top-notch isolation in your room What Brien and I were talking about is that you might be able gain a few inches of head room by using the space between the trusses for the joists that will hold your new inner-leaf ceiling. There are some techniques you can use to save space, and that is one of them. You can "interleave" your new joists between your existing trusses, thus allowing the ceiling to be a couple of inches higher than it would be otherwise. Another technique is to build the ceiling "inside-out", meaning the joists go below and the drywall on top, which accomplishes the same thing. But in either case, you still need to get the existing drywall off that ceiling, beef up, seal, etc. due to the 3-leaf issue, as I described previously. - Stuart -

Ok I understand now. I am willing to remove the drywall from the ceiling and do what is necessary. I am attaching another sketchup of the shell including the trusses, flooring on top and the drywall beneath. They are on layers so they can be turned off and on. What is my next step? Thanks, Bill

I have borrowed a sound meter. Please explain to me where and how to check the sound levels in the area. Bill

Soundman2020 wrote:

Yes he will.

Not if he builds inside-out ... :) - Stuart -

An inside out ceiling is too difficult first, and creates multiple air spaces in his situation second...can we agree on any of that? edit: My concerns were based on this: "Q - "You are willing to remove the existing sheetrock on the ceiling and add additional mass to the upper, bottom side of the floor yes?" A - I can add mass to the bottom which is the ceiling in the basement. I cannot add mass to the upper because that is the living space." Which sounded like the ceiling wasn't coming down....

Brien, I'm not saying NEVER come down but would not want to take it down unless it was absolutely necessary. In the area where the studio will be is over the bedroom areas of the house so this is the least active areas during the days and it will be VERY rare if I record at night. It is rare if there is much noise at all until about 10:00pm in this area . That is why I'm reluctant to take the ceiling down. My family are at the other side of the house most of the time in the living area. Can we do this based upon very little activity in the upstairs area during recording? If you were here in the basement with me now, there is no noise down here at all. I have a db meter sitting beside me now and it is at 65.0 dba SPL. Bill

I have a db meter sitting beside me now and it is at 65.0 dba SPL.

I wouldn't call that "quiet"! You have something pretty noisy going on in there. That's roughly the level of normal conversation. If you had told me it was around 35, then I'd agree that it is quiet, but 65 is another story. 65 is about one thousand times greater than 35, in terms of energy. What is making all that noise in there? - Stuart -

An inside out ceiling is too difficult first, and creates multiple air spaces in his situation second...can we agree on any of that?

Yup, for sure, if he doesn't take off the ceiling! I think that's where I was disagreeing with you: you were assuming he was going to leave it on, I was assuming he was going to take it off. I think we are on the same wavelength now!

I have borrowed a sound meter. Please explain to me where and how to check the sound levels in the area.

What I would do is set up your DAW with full range speakers in your room just as it is right now, and play your baddest, meanest, heaviest, thumpy-est, screaming-ist, "bassy-est" track, at around 115 dB SPL on the meter (C-weighting, slow response). That is REALLY LOUD, so wear ear protection, and warn your neighbors that this is just a test, and it wont last long. You really want a track with pounding, thudding drums (both kick and snare), lots of bass, and some grinding, screaming electric guitars, and plenty of crashing cymbals, keyboards and vocals. In other words, something that covers the entire spectrum, with plenty of low end. The reason for choosing the level of 115 dB (average) is because it is roughly the level of live acoustic drums, which is about as loud as things are likely to get. With the loudest section of that song looping over and over, close all the doors and windows to your room, and take measurements in various places around the house, both inside and outside, noting them all down on a piece of paper under the heading "loudest" readings. Probably the most important readings will be those in the room overhead, the room next door, and in the garden outside, a few meters away from the room on different sides, but take several readings in different rooms around the house, and different locations outside. Now pick the loudest of those readings, and go stand at that location again while someone else gradually turns down the level until the most critical, "sound-sensitive" member of your family thinks that the level is now acceptably quite in that location. ("Acceptably quite" as in even a cranky sleeping baby wouldn't notice it.) Keep the DAW playing at that level, and walk around all the other places where you took readings before, and now note down the new "quiet" reading for each location. Finally, shut off the DAW completely, and walk around all of the locations one more time, noting down the final "ambient" readings. Now you have real numbers on which to base your decision. The difference between 115 dB and your highest "loud" reading gives you a rough idea of how much isolation you are getting right now. The lowest "quiet" reading gives you a rough idea of how quiet you need to be. The difference between those two (highest "loud" and lowest "quiet") tells you how much ADDITIONAL isolation you need, and the difference between the quietest "quite" and 115 dB is how much TOTAL isolation you need. That's the most important figure. With those figures in hand, we can then look at different methods of getting that level of isolation. Note: This isn't exactly a highly accurate scientific test of real levels, but it does give you a damn good idea of where you are, where you need to be, and what you need to do to get there. - Stuart -