Hi everyone, long time lurker, first time poster.
I'm building a new studio space over my garage. First draft of plans attached. I would *love* any feedback from anyone.
Type of music is mixed but indie rock. Lots of samples of the sorts of artists I work with on my Discography on the website in my sig.
The plan is that the red walls will be 6" staggered stud, 2x 5/8 drywall + Green Glue + mineral fiber. This should get me as soundproof as my current studio space which I'm happy with. Windows will be doubled up. I'm not really worried about soundproofing.
The roof will be vaulted, 12' at peak, 8' at edges (dotted lines on drawing). On the drawing the green rectangles are clouds / lighting panels. The purple rectangles are rugs / flooring will be oak hardwoods. The blue rectangles are 703 panels and / or diffusors. There are two closets, one for gear, and an amp iso closet.
The control room will be a diamond-shaped pentagon with dimensions from ~17' - ~15', symmetrical ceiling w/ max height 12' / min 8' with a big bass trap in the corner.
What do you guys think about this control room space? It's my big issue right now.
I'm building over a garage with wooden rafters. Any concerns about the floor?
Let me know what information I forgot to provide. :lol:
Studio Over Garage
Originally posted at johnlsayers.com, topic 19296.
*bump*
any comments at all about my plans?
Ooops! Looks like I missed your first post somehow! :oops: :oops: Sorry about that!
So firstly, WELCOME to the forum! :)
Building a studio on an upper floor is more complex than building on the ground. It presents both acoustic and practical issues: Acoustic in the sense it is harder to isolate a room that isn't resting on the ground, and practical in the sense that doing so requires a lot of mass (heavy building materials), meaning that the existing structure might need beefing up to be able to support it safely. That said, if your isolation needs are low, then it should be possible to do. That leads to the big question: How much isolation do you need, in terms of decibels?I'm building a new studio space over my garage.
How "soundproof" is your current place? Measure that, and that will answer the question "how much isolation do you need?". Also, is your current studio built at ground level, or on a higher floor? There's a big difference. If your current place is built on a concrete slab on grade, and you build the walls of your new studio the exact same way as teh old one, then you will get much less isolation overall due to the floor problem.This should get me as soundproof as my current studio space which I'm happy with.
The size and basic layout look OK, but have you also considered soffit-mounting your speakers? That room is perfect for an RFZ design control room, and that just begs to have the speakers correctly mounted in soffits, to also avoid all the typical artifacts associated with free-standing speakers. Also, you are only showing one leaf of your rooms, and only one door in each doorway: For good isolation you need decoupled two-leaf walls, and two doors in each opening, back-to-back.The control room will be a diamond-shaped pentagon with dimensions from ~17' - ~15', symmetrical ceiling w/ max height 12' / min 8' with a big bass trap in the corner. What do you guys think about this control room space? It's my big issue right now.
Yep! The wooden joists. How much extra weight can they take? You need to know how much additional dead load and live load they can handle, to see if it is feasible to build your studio up there or not. You are talking about adding a couple of tons of load up there, so it is critical that you get a structural engineer to evaluate that, and tell you if what you are proposing is safe or not, with the existing structure. If it is not safe, then he can also tell you what you need to do to beef it up, so it can take the load. That would be my main concerns: Structural safety, and isolation. - Stuart -I'm building over a garage with wooden rafters. Any concerns about the floor?
Thanks for replying, Stuart!
I would be happy with 55dB or better. 60+ dB would be ideal. Help me understand the isolation issues regarding the floor. Under the studio is my garage. I'm unconcerned about leakage between the studio and the garage. Leakage from the studio through the garage and out to the world (and vice-versa) would be a problem however I have a hard time believing that there will be that much transmission, if so, I can beef up the iso under the flooring.That leads to the big question: How much isolation do you need, in terms of decibels?
No, I really haven't, but it's a good idea. I don't own a pair of monitors that I would consider soffit-mounting, and have not monitored with soffit-mounted speakers since sometime in the 1990s. But I am intrigued by the possibilities. In theory, if I wanted to get a set of speakers that could / should be soffit-mounted, I can build the soffits later? Or as I'm thinking about it, I suppose that for coupling reasons you'd ideally want the soffits framed tightly into the walls...?The size and basic layout look OK, but have you also considered soffit-mounting your speakers? That room is perfect for an RFZ design control room, and that just begs to have the speakers correctly mounted in soffits, to also avoid all the typical artifacts associated with free-standing speakers.
That's my fault, the walls are spec'ed as 6" staggered stud walls, and doors are doubled, but not shown on the drawing.Also, you are only showing one leaf of your rooms, and only one door in each doorway: For good isolation you need decoupled two-leaf walls, and two doors in each opening, back-to-back.
The joists are: whatever the engineer tells me I have to use :) I have to throw out the existing joists :(The wooden joists. How much extra weight can they take?
Think of it this way: If you want to build a kick drum or any drum, really!), then you stretch a flexible membrane over a large air cavity, and it resonates wonderfully! Sort of like stretching a wooden floor out over a garage space, for example... :) It will resonate at certain frequencies: those frequencies could be rather loud, and their sound could be transmitted to the outside world rather well, through the garage. Even a concrete floor over a room can be problematic, and concrete is a lot stiffer and much heavier than wood. That would be sort of like replacing the beater head on your kick drum with a steel plate: the drum still rings and resonates, but it sounds very different. A concrete "slab on grade" does not have this problem, since the slab is resting directly on the ground, so you have the entire planet acting as a damper! It's hard to beat that... That would be like getting twenty people to all put there hands up against the kick drum head, and also filling the entire drum body with rubber: no more resonance at all. But any floor that isn't damped (either by Mother Earth or in some other way) will resonate, just like a drum head. So any room built on top of that, is basically sitting on top of a drum. That's not a good place for a studio to be. Yes, there are ways of dealing with that, and yes one of those ways is to build the studio-floor/garage ceiling as a proper fully-decoupled MSM isolation system, but doing so goes back to the issue I mentioned with weight: Lots of it! Another option is to float your floor, but that is a daunting task, and very expensive. Here's a very interesting thread about that: viewtopic.php?f=2&t=8173 So there are options, but they do add extra cost and complexity.Help me understand the isolation issues regarding the floor. Under the studio is my garage. I'm unconcerned about leakage between the studio and the garage. Leakage from the studio through the garage and out to the world (and vice-versa) would be a problem however I have a hard time believing that there will be that much transmission, if so, I can beef up the iso under the flooring.
For slab on grade, 55 is doable, and 60 could be done if the budget is good enough. But on a wooden floor? Mmmmm..... 45 would be a more realistic goal.I would be happy with 55dB or better. 60+ dB would be ideal.
Right! Build the soffits now, even if you don't put speakers in them yet. On the other hand, pretty much any speaker sounds much better soffit-mounted, with the obvious exception of rear-ported and side-ported speakers. So regardless of what you have, you could soffit those now and then replace them later with something more suitable, if you want. Barefoot has done a design for a soffit that has a removable bezel on the front, so you can later replace the speaker without having to dismantle the entire soffit.In theory, if I wanted to get a set of speakers that could / should be soffit-mounted, I can build the soffits later? Or as I'm thinking about it, I suppose that for coupling reasons you'd ideally want the soffits framed tightly into the walls...?
:thu:That's my fault, the walls are spec'ed as 6" staggered stud walls, and doors are doubled, but not shown on the drawing.
Smart move! :) But you might not have to throw them out: it might be possible to "sister" them, or support them on a steel beam, or some such. - Stuart -The joists are: whatever the engineer tells me I have to use :) I have to throw out the existing joists :(
How could you say that, without first asking me about the garage that the sound is leaking into?For slab on grade, 55 is doable, and 60 could be done if the budget is good enough. But on a wooden floor? Mmmmm..... 45 would be a more realistic goal.I would be happy with 55dB or better. 60+ dB would be ideal.
** BUMP ** and ** UPDATE **
Hi all - well, it's getting to be "nut-cuttin' time" as the cowboys in Texas say. Time to finalize designs and sign a contract.
Stuart, I've mulled the input you gave me and decided to grab some JBL LSR32s and soffit mount them. I've no significant experience mixing with soffited monitors but no time like the present to learn and I love JBLs generally, so I'm just going to leap, primarily based on the overwhelming advice of this forum. I've also decided to much more closely approximate John's original "corner control room" design by tightening the wall angles to emulate his RFZ. The only difference is that the room is just a little shorter (less deep) but the wall angles are exactly the same as his example.
My specs for the various walls and the floor are included in the design. I've posted the design with furniture and gear in order to approximate the layout of the studio. I wish I had time to learn sketchup but alas! There are only so many hours in a day :(
The windows are double vinyl windows (even where not shown correctly on diagram) each rated 34 STC. The front windows are 4x5 to match my home. The rest are 6x1 or 4x1 mounted at 6' to minimize reflection / sound transmission issues
The green rectangles are clouds w integrated lighting. The purple rectangles are rugs.
The dotted line represents the vaulted roof. 8' at the walls to 12' in the center. The control room has a symmetrical vaulted ceiling.
The big doors are 4x8' double doors that we'll custom build with 2x4s, 3/4" sheathing, mineral fiber inside, and 403 panels on the outside. They'll be heavy and usually open. When closed I hope to get 30 STC from them.
Note: the garage is 32 STC with the door closed. Sound transmission from the studio to the garage is not a concern, except insofar as it leaks outside (or into the studio via the garage).
Goal 1: 60 STC to outside / 70 between tracking / control. Anyone think this is achievable?
Goal 2: decent RFZ at mix position. Have I got it right?
Question: what about the voids where the two walls meet (in the entrance deadlock and the bathroom)? Is it OK to sheetrock over the joint in the two walls?
I'd sure love to hear any feedback, however critical.
Edit: changed attachment to JPG
Nice! Those are passive, IIRC, so you'll need an amp and a phase-linear parametric equalizer. What do you have in mind for those?and decided to grab some JBL LSR32s
:thu:I love JBLs generally,
There are some very good video tutorials on YouTube that teach you how to use SketchUp in a few hours: Very much worthwhile.I wish I had time to learn sketchup but alas!
When you say "double", do you mean they are double-glazed? As in two thin panes of glass separated by a thin space, all mounted in the same frame? If so, then that's not what you need. Using two of those together will create a four-leaf system, which will have pretty lousy low frequency isolation.The windows are double vinyl windows
Careful with STC ratings... STC is no use for measuring studio isolation: It was originally meant for putting a single number to indicate isolation in typical house/office/shop/school walls, where the "noise" is moistly voices, telephones, HVAC air noise, typewriters, office equipment, and suchlike. Not meant for music. STC does not even consider the bottom two and a half octaves of the music spectrum at all! Drums, bass, the low end of keyboards and electric guitars, etc. just aren't taken into account when calculating the STC rating for a structure. so you can quite easily have a wall rated at STC-50 that does a really lousy job of isolating a studio, and another wall rated at STC-40 does an amazing job. When talking about studio isolation you should be talking what is knows as "Transmission Loss" or "TL", which is basically a graph that shows isolation across the entire spectrum, and can be summed up reasonably accurately by measuring the "inside" and "outside" levels with a decent sound level meter set to "C" weighting and "slow" response. "STC-40" does not mean that the wall provides 40 dB of transmission loss...... rated 34 STC.
That sounds like you are planning to build hollow-core doors. Not a good idea. That's basically two membranes on a frame, and is a resonant system. The entire door will resonate a a set of frequencies that are governed by the mass of the panels on each side (surface density) and the depth of the cavity between. They won't isolate well at all, and could cause some bad issues with the room acoustics, both when open and also when closed. Studio doors should be solid-core, not hollow core. Build them up from several layers of thick, heavy materials, such as MDF, plywood, drywall, even lead sheeting and MLV can be used, if you need to save space and still get high mass. And they will be way too heavy to be hung on hinges alone, give the huge moment arm of having them fully extended: so you will need to put wheels on them, to carry the weight. And you will have a rather interesting time figuring out how to get good air-tight seals on those! That is going to be the biggest issue with those doors. Since there is no central post for them to close against, they have to close against each other: how you do that and still get acoustic class seals, is going to be a major challenge.The big doors are 4x8' double doors that we'll custom build with 2x4s, 3/4" sheathing, mineral fiber inside, and 403 panels on the outside.
That's not much! Not even as good as an average house wall. Even conversation will be clearly audible through that, yet you show drums on one side and vocals (or piano) on the other: I can't see that working, with only STC-30.When closed I hope to get 30 STC from them.
Achievable? Yes, but not the way you show it! You have single-leaf walls everywhere, except between the LR and CR. In order to get get 70 dB of isolation with a single-leaf wall, it will have to be extremely massive: According to the mass law equations, you would need something that has a surface density of about 8000 kilograms per square meter, which works out to roughly 3 meters of solid concrete... That's a really expensive way of getting your isolation! Two-leaf MSM is a much better method, and waaaay cheaper. You could get STC-70 with simple 2x4 studs and several layers of drywall for a fraction of the cost of a single leaf. So I'd really suggest that you change your design to make everything into a fully decoupled 2-leaf MSM rooms.Goal 1: 60 STC to outside / 70 between tracking / control. Anyone think this is achievable?
Perhaps, but the only way to tell for sure is by ray-tracing. I have the impression that your side walls are not angled quite enough, but you should ray-trace that to confirm.Goal 2: decent RFZ at mix position. Have I got it right?
No. That would couple the two leaves together. Each room must be built as a separate unit, self-standing: a stud frame with drywall on only one side of the framing, even if it is several layers of drywall. No room can touch any other room (not even a single nail), and no room can touch the outer leaf either. You also should not have a room inside your MSM air gap, which is basically what your entrance lobby is, between the two sliding glass doors. That lobby should be treated as if it were part of the outer leaf. Overall the layout looks good, but I'd really suggest that you should change to proper 2-leaf MSM design, all around (not just between LR and CR so you can get the type of isolation you want. And going back to the original point: if this is still being built over your garage, on the second floor, then all bets are off: there's no way that typical attic joists are going to support all that weight. We are talking about many, many tons of mass to get the isolation levels you are talking about, so your joists should be your first priority: call up your structural engineer and get him to give you a written report on how much load your existing joists can take, and another report on what you need to do to them so that they can support the type of load we are talking about for building your studio. Second, even if the joists could support the weight, you won't get 70 or even 60 dB of isolation, since the floor is a major flanking path, You might get 30-something db of isolation, with luck, but only if you put the drums on a well isolated riser platform. And the bass amp, too. - Stuart -Question: what about the voids where the two walls meet (in the entrance deadlock and the bathroom)? Is it OK to sheetrock over the joint in the two walls?
I have a pair of Yamaha M2 power amps that I plan on using with the speakers in biamp mode. You recommend using equalizers in the control room? I have never done so. Why?Nice! Those are passive, IIRC, so you'll need an amp and a phase-linear parametric equalizer. What do you have in mind for those?and decided to grab some JBL LSR32s
I explained poorly. The outer windows are double glazed in order to match the exterior of the house, then I'm planning on adding a single glazed piece of heavy glass over that. How do you recommend building well-isolated windows? Is there a tutorial on the website perhaps?When you say "double", do you mean they are double-glazed? As in two thin panes of glass separated by a thin space, all mounted in the same frame? If so, then that's not what you need. Using two of those together will create a four-leaf system, which will have pretty lousy low frequency isolation.The windows are double vinyl windows
It's the rating offered by window vendors everywhere :( It's all I have to work with.Careful with STC ratings...... rated 34 STC.
[/quote] Why is this bad? The doors are similar to a wall: high-mass 2x4 frame, sheathing, damping material, and absorption on the outside.That sounds like you are planning to build hollow-core doors. Not a good idea. That's basically two membranes on a frame, and is a resonant system.The big doors are 4x8' double doors that we'll custom build with 2x4s, 3/4" sheathing, mineral fiber inside, and 403 panels on the outside.
Two points: 1. when I said I hope to get STC 30, my point was that my expectations and needs are low. 2. considering I'm using a single tracking room right now with no ability to separate anything, 30 STC is a very significant difference and quite usable from a recording standpoint. Perhaps you have a suggestion for a better way to build a very large doorway that, when open, will allow the room to function as a single, larger room; but when closed will provide isolation without being a huge reflective piece of glass? I'm totally open to suggestion. Have you seen this done well anywhere? I'd love a space with a little iso, but I'm wholly opposed to iso "boxes."That's not much! Not even as good as an average house wall. Even conversation will be clearly audible through that, yet you show drums on one side and vocals (or piano) on the other: I can't see that working, with only STC-30.When closed I hope to get 30 STC from them.
Is a staggered stud wall considered single leaf? I was not aware of that. What do you think is the best STC you can get with a staggered stud wall?Achievable? Yes, but not the way you show it! You have single-leaf walls everywhere, except between the LR and CR.Goal 1: 60 STC to outside / 70 between tracking / control. Anyone think this is achievable?
I used the angles John provided in his corner control room example which should mean the side walls are the same. Since the front wall is about a foot closer to the back than his original example, I've placed absorbers on the rear wall to counter first reflections there.Perhaps, but the only way to tell for sure is by ray-tracing. I have the impression that your side walls are not angled quite enough, but you should ray-trace that to confirm.Goal 2: decent RFZ at mix position. Have I got it right?
So it should or shouldn't be sheetrocked? You answer seems to say yes and no.No. <snip> You also should not have a room inside your MSM air gap, which is basically what your entrance lobby is, between the two sliding glass doors. That lobby should be treated as if it were part of the outer leaf.Question: what about the voids where the two walls meet (in the entrance deadlock and the bathroom)? Is it OK to sheetrock over the joint in the two walls?
As I mentioned previously, the existing joists are being discarded, so we have the ability to specify whatever joists are required, up to budgetary constraints, I suppose. It should be a non-issue.And going back to the original point: if this is still being built over your garage, on the second floor, then all bets are off: there's no way that typical attic joists are going to support all that weight. We are talking about many, many tons of mass to get the isolation levels you are talking about, so your joists should be your first priority: call up your structural engineer and get him to give you a written report on how much load your existing joists can take, and another report on what you need to do to them so that they can support the type of load we are talking about for building your studio.
Stuart, do you mean 30 dB of isolation between the studio and the outside, or between the studio and the garage? As I mentioned previously, sound leakage from the studio into the garage (and vice versa) is not an issue, except insofar as it then communicates to the outside. Also I find 30 dB hard to understand. A typical floor between two stories of a house provides more than 30 dB of noise reduction between floors. For that matter my garage door provides 32 dB of isolation and it's just two pieces of metal sandwiching a bunch of rigid fiberglass insulation. Can you help me understand your concerns? You're saying that: hardwood floors + 3/4" decking + green glue + 3/4" decking + joists + mineral fiber + 5/8" sheetrock will offer me 30 dB of attenuation? The reason I find this odd is that homes in Texas are usually built on pier and beam foundations sitting on top of a vented crawlspace and I *know* these floors are more than 30 STC because I've lived in them and made noise in them my whole life. The floor I'm planning on building should offer more attenuation than the typical pier and beam flooring (due to extra layer of ply + green glue). You keep throwing up the red flag on building on a second story, almost to the point where I'm worried that I will have to call off the entire project. I am not about to jump into this project only to learn that after everything, I have no iso and every leaf blower in the neighborhood is making its way onto my acoustic guitar tracks. I really appreciate your willingness to offer feedback! I just need more help understanding it.Second, even if the joists could support the weight, you won't get 70 or even 60 dB of isolation, since the floor is a major flanking path, You might get 30-something db of isolation, with luck.
Several reasons: 1) If you soffit mount your speakers, the soffits automatically correct the power imbalance between lows and highs that was already being corrected by the crossover circuitry inside the speaker. Since you no longer need that electronic correction, you have to "undo" it with a parametric equalizer that allows you to set a low shelf filter of -6dB, starting at the center frequency of baffle step response for your speakers. Active speakers normally have this control built in as part of the amplifier circuitry, and it is usually labeled as "bass roll of", "bass tilt", "room correction", or something similar, but passive speakers seldom have that, so you need to add it externally. 2) Consoles and desks often cause a frequency response dip in the mid range, due to comb filtering and other issues, which you may need to compensate for with equalization. 3) In general it's good practice to roll off the highs just a little. Your room acoustic treatment should already do that for you to a certain extent, but if it isn't enough (or too much!) then you might need to correct that too. Finally, there are occasionally a couple of other things with the room response itself that an equalizer can help correct, to varying extents.You recommend using equalizers in the control room? I have never done so. Why?
OK; so that would be a three-leaf system, not a four-leaf, so not quite as bad in the low end, but still not as good as normal two leaf. The issue is that any 3-leaf system will always isolate worse in the low end than the equivalent two-leaf system, all other factors being equal. You can normally compensate for that by doubling the mass on the middle leaf (a 3-leaf system is most effective when half of the total mass is on the middle leaf), or increasing both air gaps, but if you use standard double-glazing units, that option isn't open to you either, since the glass thickness and the outer-to-mid air gap are set by the factory unit. so your only remaining option is to go extremely massive on the inner-leaf glass, and increase that last air gap as much as you possibly can. So it's not a "death sentence" for isolation, since you can compensate, but the situation is best avoided where possible.I explained poorly. The outer windows are double glazed in order to match the exterior of the house, then I'm planning on adding a single glazed piece of heavy glass over that.
The same as the walls: fully-decoupled 2-leaf MSM. In other words, one pane of laminated glass in the outer leaf, that matches the surface density of the rest of the outer leaf, and the second pane of laminated glass in the inner leaf, that matches the surface density of the rest of the inner leaf.How do you recommend building well-isolated windows?
Yeah, unfortunately that's true: Even the so-called "acoustic" windows seem to be rate like that in advertising, and you have to dig deep to find the real isolation numbers. However, you can still estimate the isolation from the normal acoustic equations: Mass Law if it is a single pane of glass, and the MSM equations for double-glazing.It's the rating offered by window vendors everywhere
The two leaves of an isolation wall are decoupled (two separate frames, one leaf on each), and separated by a large air gap. A hollow-core door has both leaves on the same frame, and only a very narrow air gap. So the MSM resonant frequency is fairly high, and the leaves are coupled anyway.Why is this bad? The doors are similar to a wall: high-mass 2x4 frame, sheathing, damping material, and absorption on the outside.
STC-30 is about what you get from a typical house wall (2x4 studs, 10mm drywall on each side, no insulation), which is not very good at all. Normal conversation is clearly audible through that. Loud music sounds like it is in the same room, with no wall at all. Drums, for example, measure at about 115 dB: through an STC 30 wall, they would come through at about 90 dB or so. Typical singing vocals are around 80-90 dB: so in other words in your vocal mics, the drums would be coming in a bit louder than the vocals... Studios are normally isolated to around 50 dB TL (not STC-50, which is much lower), and drum booths are usually isolated to 60 or even 70 dB. In high-end pro studios, it can go even higher. The best isolated studio on the planet is Galaxy in Belgium, and all their rooms get over 100 dB of isolation. In other words, even gun shots in one room are practically inaudible in the next room. That's probably out of the question for home studios, but 60 and 70 is do-able.1. when I said I hope to get STC 30, my point was that my expectations and needs are low. 2. considering I'm using a single tracking room right now with no ability to separate anything, 30 STC is a very significant difference and quite usable from a recording standpoint.
To be honest: No, I haven't seen that done anywhere. Studios normally have either large hinged doors or large sliding glass doors. I have never seen large bi-fold doors that provide high levels of isolation. I'm not saying it is impossible: Just very hard to do. That's probably why most pro studios don't try to do it: they prefer to spend their money on things that can be done at more reasonable cost. There might be studios out there that have accomplished it, but none that I'm aware of. Probably your best bet is large sliding glass doors. I'm not sure why you are concerned about a large reflective piece of glass, when a large reflective piece of wood, such as would be the case with the doors you proposed, would be pretty much the same, acoustically. A glass door and a wooden door that provide the same level of isolation, would also provide roughly the same level of reflection, so the room would not sound very much different if you make your doors out of wood, glass, steel, drywall, or any other high density material.Perhaps you have a suggestion for a better way to build a very large doorway that, when open, will allow the room to function as a single, larger room; but when closed will provide isolation without being a huge reflective piece of glass? I'm totally open to suggestion. Have you seen this done well anywhere? I'd love a space with a little iso, but I'm wholly opposed to iso "boxes."
If you put drywall on only one side of it, which is what you seem to be proposing, then it is single-leaf, yes. If you put drywall on both sides then it is two-leaf, but I assume you aren't doing that because you show the staggered stud wall right next to the outer brick wall of the building, so if you put drywall on both sides you would have a 3-leaf system, and therefore poor isolation in the low frequencies. It would be a lot cheaper (and more effective) to just build a single stud frame for those walls, and put your drywall on that.Is a staggered stud wall considered single leaf? I was not aware of that. What do you think is the best STC you can get with a staggered stud wall?
Good. You'll need deep absorption on the rear wall anyway, since it is an RFZ room and not big enough for diffusion. John normally uses hangers on the rear wall, so you might want to consider that as an option too. Or just stay with thick absorption: that also works. Is the room the exact same width as John's room? If not, then you will have to adjust the wall angles as necessary to get the RFZ. Every room is different: unless you copied the entire room identically in all aspects, then you still need to go through all of the usual processes to determine if you really do have an RFZ, and to determine what type of treatment you will need, how much of it you will need, and where you will need it.I used the angles John provided in his corner control room example which should mean the side walls are the same. Since the front wall is about a foot closer to the back than his original example, I've placed absorbers on the rear wall to counter first reflections there.
Not the way you asked the question, no. You seemed to be asking if you could drywall the gap between leaves, and the answer to that is no, you can't, as it would create a flanking path. The correct way to do that, is to build the lobby as a separate room, with additional glass doors on each side, and completing the inner-leaf for that room with drywall where needed.So it should or shouldn't be sheetrocked? You answer seems to say yes and no.
Ok, that's great! I didn't recall that you were planning to replace that floor entirely. If that's the case, then have you considered doing a "beam and block" type of floor, or even a concrete floor?the existing joists are being discarded, so we have the ability to specify whatever joists are required, up to budgetary constraints, I suppose. It should be a non-issue.
I think you are missing the point: the issue is not about isolation to the garage, but rather that the garage itself will act as a huge resonant chamber, and since all of your rooms are on top of the same garage, unless that floor is well damped and really good at isolating, the resonance caused by any of the rooms will be returned to all the other rooms, through the garage. People tend to underestimate the power of resonance, but it is a powerful force. It has been known to destroy huge bridges and other structures, as well as machinery and equipment, so it can certainly cause sound to be transferred from one room to another.Stuart, do you mean 30 dB of isolation between the studio and the outside, or between the studio and the garage? As I mentioned previously, sound leakage from the studio into the garage (and vice versa) is not an issue, except insofar as it then communicates to the outside.
You seem to be confusing "30 db of isolation" with "STC-30". They are not the same thing at all. To determine the STC rating for a wall, door, window, or whatever, you start by measuring the actual transmission loss at 16 specific frequencies between 125 Hz and 4kHz. You do not measure anything above or below that range, and you do not measure anything in between those 16 points. Just those 16, and nothing else. Then you plot those 16 points on a graph, and do some fudging and nudging with the numbers and the curve, until it fits in below one of the standard STC curves. Then you read off the number of that specific curve, and that number is your STC rating. There is no relationship to real-world decibels: it is just the index number of the curve that is closest to your curve. When you measure the isolation of a studio wall, you want to be sure that it is isolating ALL frequencies, across the entire spectrum from 20 Hz up to 20,000 Hz, not just 16 specific points that some body chose 50 years ago, because he thought they were a good representation of human speech. STC does not take into account the bottom two and a half octaves of the musical spectrum (nothing below 125Hz), nor does it take into account the top two and a quarter octaves (nothing above 4k). Of the ten octaves that our hearing range covers, STC ignores five of them (or nearly five). So STC tells you nothing useful about how well a wall, door or window will work in a studio. The ONLY way to determine that, is by look at the Transmission Loss curve for it, or by estimating with a sound level meter set to "C" weighting (or even "Z")m and slow response, then measuring the levels on each side. That will give you a true indication of the number of decibels that the wall/door/window is blocking, across the full audible range. It is quite possible to have a door rated at STC-30 that does not provide even 20 decibels of actual isolation, and I can build you another wall rated at STC-20 that provides much better than 30 dB of isolation. There simply is no relationship between STC rating and the ability of a barrier to stop full-spectrum sound, such as music. STC was never designed for that, and cannot be used for that. Then there's the issue of installation. You can buy a door that really does provide 40 dB of isolation, but unless you install it correctly, it will not provide that level! If you install it in a wall that provides only 20 dB, then the total isolation of that wall+door is 20 dB: the same as the worst part. even if yo put a door rated at 90 dB in that wall, it would STILL only give you 20 dB. Isolation is only as good as the weakest part of the system. Next case: You buy a 40 dB door and put it in a 40 dB wall, but you don't put seals on the door: your isolation will be about 20-something dB: Those tiny gaps around the edge of the door can easily cost you more than 10 dB in isolation, and perhaps much more. Sealing is critical to isolation. In other words: even though your garage door might well be rated "STC-32", it mostly definitely does not provide 32 dB of isolation. Check for yourself: Set up your sound system inside your garage with good full-range speakers, and play loud rock music at a level of about 100 dB, as measured inside the garage, about 3 feet from the door. Now go outside and measure the level, also at about 3 feet from the door: I guarantee you that the reading is way higher than the 68 dB that you would expect if the door really were providing 32 dB of isolation. Probably more like 80 dB, for a typical door in a typical garage. So forget STC as a useful indicator, and stick to TL graphs.Also I find 30 dB hard to understand. A typical floor between two stories of a house provides more than 30 dB of noise reduction between floors. For that matter my garage door provides 32 dB of isolation and it's just two pieces of metal sandwiching a bunch of rigid fiberglass insulation.
It might offer you that, or it might be more, or it might be less. It all depends on how you build it, and how the rest of the structure works, and how deep those joists are. that specific combination is not in IR-766, but the ones that come closest are around STC-45 to 50, which might or might not be 45 to 50 dB of real-world isolation. More likely to be "not"! :) I would guess somewhere in the region of 35 to 40 dB TL, in real life, assuming that we are not talking about impact noise: I would estimate IIC much less than 40.You're saying that: hardwood floors + 3/4" decking + green glue + 3/4" decking + joists + mineral fiber + 5/8" sheetrock will offer me 30 dB of attenuation?
Unfortunately, with acoustics things often don't work out the way you expect they logically should, because acoustics isn't intuitive! We can't see, taste, smell or touch sound, and we only hear it on one location at a time: whereas we can see, smell and touch things that are going on across a wide range of distances, we can only hear what is going on exactly at the point where our ears are located. The light you see coming from an object 100 meters away has not changed at all on its journey to your eyes: you see it exactly the way it is. But the sound has changed considerably in its journey form that point to your ears, and the point where you listen to it will change the way you hear it. Very often moving your ears just a couple of inches left or right, up or down, forwards or backwards, can reveal large differences in the sound field: Our brains are not much good at making a mental map of that sound field around us, and even less good at intuitively understanding how that sound field got to be the way it is, and how it is interacting with the room and objects in it. So we don't "get" sound the way we "get" light. We make assumptions about how sound behaves, thinking that it should work the same way light does, when in reality it is totally different. So assuming that sound will do something that seems logical and intuitive and obvious, is frequently wrong. For example, if you have two sheets of smoked glass, and you insert a third sheet between them, then in reality it gets darker: less light gets through. Logical, intuitive. But not so with sound: you can have two panels in a wall that are isolating to a certain extent, and inserting a third panel between them can make the sound LOUDER at certain frequencies. That would be like adding the middle piece of dark glass and seeing the light get brighter! Or redder! Not logical, not intuitive, but absolute fact, and fully explained by the laws of physics, due to the effects of resonance. Because sound does NOT behave like light does. So assuming things about acoustics can be a mistake: it might not turn out the way you intuitively expected! Rather, you should do the math and see what the equations say: Believe them, not your intuition. Here's a graph put out by the "Soundproofing Company" that clearly illustrates this point: You would think that the STC-42 wall should be MUCH better than that STC-32 wall, but in reality the STC 32 is way better for all frequencies below about 110 Hz (ie, drums, bass, low end of keyboards and guitars, trucks, planes, thunder, etc.), and they are the same above about 1600 Hz. The only place where teh STC-42 wall is better, is between about 120 Hz and 1600 Hz... which, curiously, is the roughly the human voice range... At all other frequencies, the STC-32 wall is better or the same. Not what you would expect at all, intuitively, and certainly not what the salesman at Home Depot is going to tell you when you go to buy a door or window! :)The floor I'm planning on building should offer more attenuation than the typical pier and beam flooring (due to extra layer of ply + green glue).
If you are going to re-do your floor, and budget is not an issue, then you certainly can get good levels of isolation for your second-story build. Many years ago I was involved in the installation of a post production facility here in Santiago that included a couple of really nice recording studios. The entire facility was built in the second floor of an old factory building, with brick walls and wood floors. They designed and built the recording studios properly, and even floated their floors, and they did attain excellent isolation and good acoustics. But it cost them a lot of money. I wasn't involved in the acoustic design: I did the design and installation for the video post suites, not the audio suites, but I saw what they did, and how well it worked. So it can be done, provided that it is done properly. In your case, you say that isolation isn't a big deal, and that 30 to 40 dB between rooms is fine for you: that is most definitely achievable, and you could probably get 50 dB as well, with good design and careful construction. So don't give up on this! If budget is not an issue, then you can get great isolation, even on the second floor. Just be aware that is is more expensive and harder to do than on the ground floor. That's all I'm saying: there are issues with resonance, damping, and structural integrity that have to be taken into account for upper-floor studios, that aren't an issue at all for ground floor studios. I'm not trying to be a wet blanket on your project! Not at all! So please don't get me wrong. I'm just pointing out some of the pitfalls that you might not have been aware of, so that you can avoid them. With enough money, you can isolate pretty much anything to high levels. - Stuart -You keep throwing up the red flag on building on a second story, almost to the point where I'm worried that I will have to call off the entire project. I am not about to jump into this project only to learn that after everything, I have no iso and every leaf blower in the neighborhood is making its way onto my acoustic guitar tracks.
Wow, Stuart, you are, if nothing else, a very dedicated forum admin :) Thank you for the detailed reply.
I consider myself an "advanced noob" in that I've built a small studio before that functioned more than well enough for my needs, and recorded a few decent sounding songs in that studio. Which is not to boast: I don't consider my work to be a milestone in recording history, more like, I feel like I understand my requirements well enough to usually solve my problems well enough to suit me, more or less. Which I also realize gives me just enough knowledge to be really dangerous :) So thanks, seriously, for challenging my ideas. I really like to learn and hardheads like me only learn by probing our disagreements with others. If you don't mind, I'd like to address several of the points you made in separate threads, since this thread is getting pretty lengthy with lots of different points being made.
In the meantime I have what I believe to be good news. You mentioned a beam and block floor - no, it wasn't considered, but I don't know if my existing foundation will take the weight of a concrete floor. Frankly I'm surprised that the engineer signed off on the plans I'm about to describe, but he did.
In short I will build a 2-leaf staggered-joist MSM floor. The joists that I have to discard will be retained and used to support the mineral fiber batts and the 5/8" drywall in the garage. The new engineered joists will be taller and used to support the flooring above. They and the subfloor will also be sprayed with cellulose seal per building code requirements which should add mass and sponginess - shouldn't hurt, anyway.
Shouldn't this offer a significant improvement versus the original single-leaf design? What are your thoughts about such a floor?
(fears reply re: possible low-frequency resonance of 2-leaf structures which might exacerbate the resonance problem already discussed)
That's a terrific reason :)Several reasons: 1) If you soffit mount your speakers, the soffits automatically correct the power imbalance between lows and highs that was already being corrected by the crossover circuitry inside the speaker.You recommend using equalizers in the control room? I have never done so. Why?
Well, the plan was to treat the door with an absorber, so not quite the same as glass. But you've raised good points about the door. I'll see if they can be slabs instead of hollow. Note: they aren't bi-fold, just normal hinged double doors. I prefer my idea of big double doors to sliding glass because most of the time, they'll be open, which will allow me to have an 8x8 opening in the center of the wall, as opposed to a 6x6 opening on one side of the wall.To be honest: No, I haven't seen that done anywhere. Studios normally have either large hinged doors or large sliding glass doors. I have never seen large bi-fold doors that provide high levels of isolation. I'm not saying it is impossible: Just very hard to do. That's probably why most pro studios don't try to do it: they prefer to spend their money on things that can be done at more reasonable cost. There might be studios out there that have accomplished it, but none that I'm aware of. Probably your best bet is large sliding glass doors. I'm not sure why you are concerned about a large reflective piece of glass, when a large reflective piece of wood, such as would be the case with the doors you proposed, would be pretty much the same, acoustically. A glass door and a wooden door that provide the same level of isolation, would also provide roughly the same level of reflection, so the room would not sound very much different if you make your doors out of wood, glass, steel, drywall, or any other high density material.Perhaps you have a suggestion for a better way to build a very large doorway that, when open, will allow the room to function as a single, larger room; but when closed will provide isolation without being a huge reflective piece of glass? I'm totally open to suggestion. Have you seen this done well anywhere? I'd love a space with a little iso, but I'm wholly opposed to iso "boxes."
Sorry, I meant to include the wall specifications on the diagram I posted. Building code requires the outer wall to be sheathed with 3/4" plywood. So the outer wall of the building is 3/4" plywood covered with either hardisiding (three walls) or brick (front wall). I have little say in this aspect of the construction, as my city requires me to use these materials.If you put drywall on only one side of it, which is what you seem to be proposing, then it is single-leaf, yes. If you put drywall on both sides then it is two-leaf, but I assume you aren't doing that because you show the staggered stud wall right next to the outer brick wall of the building
My plan was to make the entire back corner a bass trap. What is your though on this? I am considering either a giant superchunk (5.6 feet across!) or a panel of 4" 703 across the corner filled with fiberglass.You'll need deep absorption on the rear wall anyway, since it is an RFZ room and not big enough for diffusion. John normally uses hangers on the rear wall, so you might want to consider that as an option too. Or just stay with thick absorption: that also works.
John doesn't post dimensions, so I don't know, but the proportions are almost exactly the same. The room was made like this: I copied John's room onto my design and shortened it by one foot by lopping off the last foot where the window is to shoehorn it into the space. So all the angles are the same, but the speakers are one foot closer to the back corner. I have to believe this is better than the room I came up with :)Is the room the exact same width as John's room?
Bingo. Gotcha. I was missing the point. Well, as far as that goes, I suppose I will have to either pray for the best, or abandon the project. I've calculated the modes for the garage and there are no pileups, which is mildly reassuring, but mode calculators are only so useful. Since we're talking about bass resonance, if I discover problems after the fact, I suppose I could fill up the garage with Helmholtz resonators.... :|I think you are missing the point: the issue is not about isolation to the garage, but rather that the garage itself will act as a huge resonant chamber, and since all of your rooms are on top of the same garage, unless that floor is well damped and really good at isolating, the resonance caused by any of the rooms will be returned to all the other rooms, through the garage.Stuart, do you mean 30 dB of isolation between the studio and the outside, or between the studio and the garage? As I mentioned previously, sound leakage from the studio into the garage (and vice versa) is not an issue, except insofar as it then communicates to the outside.
I will. For the record, it's an acoustic-control garage door and it's sealed awfully well for a garage door. My garage is weirdly quiet for a garage, and it doesn't even have drywall or insulation. But you're right: I should test the garage. I'll report back my findings :)In other words: even though your garage door might well be rated "STC-32", it mostly definitely does not provide 32 dB of isolation. Check for yourself.
Here's the difference between John's drawing and my room. The difference is that the front window is about 1 foot closer to the back corner. Otherwise it's the same. Note: in my app, it appears that John's drawing is a little wonky (the angles are not symmetrical) which is why they don't precisely line up.Is the room the exact same width as John's room?
Hi Stuart, I wondered if you saw my comment regarding 2-leaf MSM floor. Is that a good or bad idea generally?
Using my clumsy skills, I raytraced the room and you are right, the walls aren't splayed enough, so I reverted back to my original plan which produces a zone that at least should be reflection free of first reflections from the side walls. Rear walls will be treated and overhead is a cloud. The room has dimensions that vary continuously from 17 ft (front-to-rear) to 8 ft (min ceiling height at rear) which I hope will reduce the chance of a severe resonance.
Thanks for all the advice and help. I appreciate your willingness to be so thorough on this forum.
Done. Result: your points are well-made. Attenuation 500 Hz and up is better than 30 dB. Attenuation at 250 is about 20 dB. Attenuation at 120 Hz is about 10 dB. I can't measure below that but intuition says virtually zero. Thank you. -- RipCheck for yourself: Set up your sound system inside your garage with good full-range speakers, and play loud rock music at a level of about 100 dB, as measured inside the garage, about 3 feet from the door.
Yup. Those all sound about right. Those are typical levels for that type of situation. - Stuart -Result: your points are well-made. Attenuation 500 Hz and up is better than 30 dB. Attenuation at 250 is about 20 dB. Attenuation at 120 Hz is about 10 dB. I can't measure below that but intuition says virtually zero.
Rip - I have the same situation in my new/future music space; on the second level above my wife's art studio. I found some old photographs of the original construction of these studios back in 1978. It appears to be 2x12" joists spanning over 21 feet across the width of the room. There's no support beam/column support in the center of the room below, so I think I might start some inquiry about how much weight I can load on the floor above. Perhaps some good news: 1) we don't need a high degree of isolation between the two studios, but anything's going to be an improvement over the bare subfloor and drop ceiling that's there now. 2) as I consider adding a more isolated booth to my room for recording, there is a smaller corner of the room that does have more support to handle the weight of the materials involved. 3) we do know that the joists are located 12" on center...which improves the load handling a bit more, but still would have a tendency to "bounce" Perhaps I'll do some low-frequency sweeps to see if I can find a mode between the upper ceiling and the concrete below. :)You keep throwing up the red flag on building on a second story, almost to the point where I'm worried that I will have to call off the entire project. I am not about to jump into this project only to learn that after everything, I have no iso and every leaf blower in the neighborhood is making its way onto my acoustic guitar tracks.