Booth Glass Window: Insulated vs Standard vs Laminated!

Hey fellas! Having a hard time choosing which glass to go with. Now first, I know the difference between these types and know that laminated is the ideal choice, but the cost of laminated is just too much of a chunk of my budget. So I'm going with the standard/annealed/solid type 3/4" thick. The thing is though, every time I call a glass shop to get prices, they keep recommending insulated for sound deadening over the standard. And it sounds tempting because the insulated glass is 1/3 the price of the standard in the same thickness. I'm getting quotes of $310-390 per sheet of 30"x24"x3/4" in standard glass and got a quote of only $120 per sheet for the same size in insulated. For laminated in this same dimension, I got a quote of $1400-1500 at a 5/8" thickness from Soundproof windows. I'm trying to keep this under $800-1000, so that is just too much. I asked my designer and he said the insulated would definitely be good at deadening high and mid frequencies, but he says he is unsure of how well it will do against low end frequencies. And since we do HipHop music, low end deadening is a priority. He has standard glass for his booth and has no issues with low frequency bleed inside his booth. So what are you guys' advice on what I should go with and what I could go with? I would like to go laminated, but it's just too expensive.

welcome! please update your profile to include your location. what does the glass supplier mean by "insulated"? it is "laminated"? or is it two thin panes with an air gap? if it is laminated, that can be very good. if it is two thin panes with air, that can be less desirable.

gullfo wrote:

welcome! please update your profile to include your location. what does the glass supplier mean by "insulated"? it is "laminated"? or is it two thin panes with an air gap? if it is laminated, that can be very good. if it is two thin panes with air, that can be less desirable.

The ones that are recommending the insulated are talking about the two sheets with air an air gap. I just got off the phone with another supplier that happens to do a lot of studios in Staten Island, and he too suggested the insulated. To be exact he suggested 3/4" over insulated on the inner both wall and 1/2" standard glass on the control room side. He says the sound will go through the solid glass quicker than the insulated. He also said as far as low frequencies go, they go through anything and will go through both types at the same rate. Lot's of confusing info. I called another place and they told me annealed glass is the same as insulated. My head is spinning!

I would not use insulated glass. I'm guessing that you are talking about "double glazing", (sometimes called "thermopanel" and similar things) meaning two thin panes in one frame, separated by a thin gap? If that's it, then forget it. That isn't much use in a studio. Two pieces of that will give you a four leaf system with a very high resonant frequency and therefore reduced isolation in the low end. Annealed glass is not the same as insulated glass: The panes in the insulated module might well be made of annealed glass, but that does not mean that insulated and annealed mean the same thing, any more than "wood" and "kitchen table" mean the same thing just because the kitchen table happens to be made of wood! What you need is two pieces of SOLID glass: no internal air gaps. If you can afford it then get laminate glass for each piece, if not then get whatever you can afford. (Laminate glass is also made from two separate panes, but there is no air gap: they are stuck together with an "interlayer" between them. Not the same as insulated glass at all!)

He says the sound will go through the solid glass quicker than the insulated.

So what????

He also said as far as low frequencies go, they go through anything and will go through both types at the same rate.

Garbage. You can isolate low frequencies effectively with glass if you do it right. The glass just has to be thick enough, massive enough and separated by a wide enough gap, period. The speed at which sound happens to go through different types of glass, air, or other things is not really a relevant factor at all in how well they isolate. It has a tiny, effect, sure, but the MAJOR factors are, as always, mass, air gap, and sealing. - Stuart -

Thanks Stu! But, I knew the lady who said annealed and insulated were the same was full of shit! From you is not the first I've heard that insulated sucks for a vocal booth. Yet, all the glass specialists keep recommending it! I read another thread on here yesterday where a guy says he originally used insulated and had to replace it with solid because of some harsh pinging sounds or something. So two more questions for you. First, what keeps making the glass guys feel insulated sound proofs better than solid? Second, I definitely can't go thicker than 3/4" and don't really want to go thinner because I am only able to get a 2" air gap between the two walls. But what do you think about the 3/4" on the inside and 1/2 on the outside that the guy suggested?

So two more questions for you. First, what keeps making the glass guys feel insulated sound proofs better than solid?

Maybe because they want to sell it?? :) Seriously, it works fine for houses, offices, hotels, etc. to reduce genera l ambient sounds quite well (street noise, etc.) and does it much better than normal single-pane window glass. But it isn't much use in a studio because that's a very different type of situation, where you need to get really loud stuff with a lot of low frequency content on one side of a wall, reduced down to practically nothing on the other side, so low that even a sensitive mic won't pic it up. That's a tall order. Needs drastic measures. So those guys aren't really hyping lousy product: Their product does work well for what it is designed to do. The problem is that they just don't have a clue about studios, even though they THINK they do...

I definitely can't go thicker than 3/4" and don't really want to go thinner because I am only able to get a 2" air gap between the two walls.

2" :shock: You can only get a 2 inch air gap between your two pieces of glass? That really isn't enough. Normal recommendation for studio windows is 8", minimum. How is your wall built that you end up with so little air gap? Can you show us a diagram of how your wall is built? If it's that thin, the 3/4 might be overkill, since your weak point is your wall itself, not your window.

But what do you think about the 3/4" on the inside and 1/2 on the outside that the guy suggested?

That's fine. Using different thicknesses is not a problem, and can help in some ways, since the resonant characteristics of each pane are different, so what makes one "ring" will be blocked by the other, and vice versa. - Stuart -

Soundman2020 wrote:

So two more questions for you. First, what keeps making the glass guys feel insulated sound proofs better than solid?

Maybe because they want to sell it?? :)

Hahaha! True, but but I would think they would rather sell the more expensive stuff than persuading me to the cheaper stuff, no? :mrgreen:

I definitely can't go thicker than 3/4" and don't really want to go thinner because I am only able to get a 2" air gap between the two walls.

2" :shock: You can only get a 2 inch air gap between your two pieces of glass? That really isn't enough. Normal recommendation for studio windows is 8", minimum. How is your wall built that you end up with so little air gap? Can you show us a diagram of how your wall is built? If it's that thin, the 3/4 might be overkill, since your weak point is your wall itself, not your window. [/quote] It's not how the walls are built, it's the size of the room. If we go with a bigger air gap, there will be hardly any interior booth space. The room is only 19' x 9'. I guess in theory we could make the front wall where the glass will be mounted have a bigger air gap. But I was under the impression that the air gap between leafs should be even all the way around. There is absolutely no way we can go bigger on the air gaps of the side and back walls. But there is room on the front wall to come out more I guess.

Soundman2020 wrote:

But the designer picked 3/4" glass because the drywall is 3/4".

Then he does not understand what he is doing! You don't need to maintain the THICKNESS of the leaves, you need to maintain the SURFACE MASS of the leaves. Glass is roughly twice as dense as drywall, so you need roughly half the thickness of glass to keep the same surface density. If you only have 3/4" drywall on your wall, then you only need 3/8" glass. So you could use 1/2" on each side if you want. 3/4" won't buy you extra isolation, since your wall is isolating less than the glass. It won't HURT any either, if you really want to go that route, but it won't do any extra for you. 1/2" on each side is plenty. - Stuart -

So, 1/2" solid glass would do just fine you think? Maybe I should price 1/2" laminated instead? Should be a lot cheaper than 3/4" laminated, right?

Are you sure you are talking about the right thing here? "Air gap" does not refer to the space between the two stud frames: it refers to the space between the two mass leaves! In other words, it refers to the total distance between the surface of the drywall on your inner leaf and the surface of the drywall on your outer leaf, measured across the cavity inside the wall. Is that 2" in your case? It doesn't look like it on the drawing, but the drawing isn't very clear... If you only have 2" there, then that implies that you built both wall inside-out. Is that the case? - Stuart -

Soundman2020 wrote:

Are you sure you are talking about the right thing here? "Air gap" does not refer to the space between the two stud frames: it refers to the space between the two mass leaves! In other words, it refers to the total distance between the surface of the drywall on your inner leaf and the surface of the drywall on your outer leaf, measured across the cavity inside the wall. Is that 2" in your case? It doesn't look like it on the drawing, but the drawing isn't very clear... If you only have 2" there, then that implies that you built both wall inside-out. Is that the case? - Stuart -

There is 2" of air gap between the actual inner an outer wall construction. Maybe I'm phrasing it wrong. The gray shaded area between the walls is a two in air gap between the walls. So the actual total distance/thickness from the surface of the control room wall to the surface of the interior booth wall is 16" he says. So that sounds like it leaves plenty of space between the two sheets of glass, not just 2" like I thought.

3/4" is massive glass. What is the construction of the walls? Going with more mass than the wall is a waste of money. Andre

AVare wrote:

3/4" is massive glass. What is the construction of the walls? Going with more mass than the wall is a waste of money. Andre

This is what he said: "1/2 COULD work but 3/4 WILL work. Mass is relative to weight, thickness is dedicated to dimensions. If the low end of a bass note takes 10' to complete a cycle, what's going to be more effective? A 1/2" panel with more mass or a 3/4" panel with more thickness? This is why a 1" air gap can attenuate better than a 1" piece of material. The wall is isolating MORE than the glass by default because it's 2 walls and an air gap. The glass, by default is your weakest link. Yes, the 3/4 drywall is equal to a 1/2 piece of glass, but it's 2 walls 1 1/2 inches worth of drywall, an air gap and insulation. A 1/2 piece of glass isn't as dense as that."

Mass is relative to weight, thickness is dedicated to dimensions. If the low end of a bass note takes 10' to complete a cycle, what's going to be more effective? A 1/2" panel with more mass or a 3/4" panel with more thickness? This is why a 1" air gap can attenuate better than a 1" piece of material.

Sorry, but that just isn't true. He doesn't seem to understand that the entire wall is a tuned system, and what "tunes" it is the mass on each leaf and the air gap, period. It must be tuned to a frequency below 50% of the lowest frequency that you want it to isolate, period. Simple physics.

This is why a 1" air gap can attenuate better than a 1" piece of material.

Garbage! A 1" air gap by itself is pretty useless, without two pieces of mass around it, and even then 1" is WAY too small to get down to the frequency that you need. It seems someone is confused here.

The wall is isolating MORE than the glass by default because it's 2 walls and an air gap.

Duh! That's why you want two pieces of glass and an air gap! :shock: What part of that is he not understanding? You can vary the masses and the air gap, but you MUST do so according to the standard MSM equation, so that your entire wall remains constant, and the easiest way of doing that is keeping the air gap constant (same gap between the two sheets of glass as their is between the two sheets of drywall), and keeping the surface density of the glass the same as the surface density of the drywall. This is not complicated.

The glass, by default is your weakest link.

Uhh, no it isn't, sorry. The SEAL is your weakest link. If he would have said that the window is the weakest part of the wall, I would have agreed, but the glass is neither "weaker" nor "stronger" than the rest of the wall, if done correctly. The toughest part is to seal it properly while maintaining the mass across the seal.

Yes, the 3/4 drywall is equal to a 1/2 piece of glass, but it's 2 walls 1 1/2 inches worth of drywall, an air gap ...

Irrelevant, because it is also TWO PIECES OF GLASS and an air gap ! Does he not understand what you are trying to do here? You cannot go with just one piece of glass in there if you want to good isolation. You need TWO panes of glass, with an air gap. Just like the wall has two panes pf glass plus an air gap. You still did not show your diagram of exactly how the wall is going to be built. Do it in SketchUp and post it here so we can see, because it seems like there are some SERIOUS issues with your design as it is. The construction details are not clear at all from that simple and rather inadequate plan: it doesn't even show the window, for example, and you might even have triple or quadruple leaf walls there, if that plan is correct. That would REALLY be a disaster, if true. - Stuart -

Soundman2020 wrote:

You still did not show your diagram of exactly how the wall is going to be built. Do it in SketchUp and post it here so we can see, because it seems like there are some SERIOUS issues with your design as it is. The construction details are not clear at all from that simple and rather inadequate plan: it doesn't even show the window, for example, and you might even have triple or quadruple leaf walls there, if that plan is correct. That would REALLY be a disaster, if true. - Stuart -

I don't know bro. All I know is I've seen his work in person and it's great quality and quiet. So I trust him without a doubt. Maybe I'm just not phrasing the terms correctly since I am only the customer, not the designer. But I put these sketches in my other thread. The first one is the the actual guts of the build. The rest are just renderings on the desired look cosmetically.

And I know this doesn't say much for construction or sound proofing, but here is his work:

Alright Stu, so we've decided to go with the 1/2" instead. I was able to get 1/2" laminated for $225 a piece vs the $310 for the 3/4" solid.

To me it looks like you have a problem with that booth. Take a look at this: Notice the walls I highlighted in pink? That looks like a 3-leaf, or even a 4-leaf wall :shock: Your low frequency isolation will not be good like that. Unfortunately, the diagrams is still inadequate to see how those walls are constructed. They look pretty, but don't actually show any useful information. However, like I noted on the graphic, if those two walls have drywall on them, then you have at least a 3-leaf structure, and maybe 4-leaf (depending on how the outer wall is built). And if there isn't any drywall on them, then why are they there at all???? Either way, it is a gross waste of space, and absolutely unnecessary. At best it just wastes several inches, at worst it also screws up your low frequency isolation. Like I said originally: there seem to be some conceptual mistakes with the design. For example, you keep mentioning that you only have a 2" air gap: that's impossible. The diagram shows an outer dimension of 4'8", and an inner dimension of 3'. Thats a difference is 20" between the inner dimension and the outer dimension of the "booth", so each wall is 10" thick. Assuming that you are using normal 2x4 framing, it is physically impossible to have only a 2" air gap. It would have to be at least 3", at the absolute minimum (if you built both walls inside-out), and probably more like 8 1/2" (if you built them both normally). Your designer seems to have a problem adding and subtracting! Something is screwed up badly here, by the looks of it. The thickness of your glass is the least of your worries. Do yourself a favor, and ask your designer to explain what this equation means: If he cannot identify it instantly, then you might want to consider what that implies... - Stuart -

Well, I know the back outer booth wall is there because there is a window along that back wall. The two side outer booth walls we have actually been thinking about removing because it might of been over kill for what we are isolating. There are no drummers or anything. All we are isolating is the control room/monitors from the vocalist. Everything else is fire trucks and booming car audio systems from the street, which is rare here. As for the 2" air gap being impossible, I don't know what you mean. I'm guessing the designer means 2" between the inner and outer wall studs. 2 2x4's mounted in a 10" space (not counting the drywall) leaves 2" between the boards. So I'm sure he wasn't referring to 2" between the actual inner and outer wall surfaces. As for the outer walls having drywall, yeah they will. I don't see why it will be a problem or how having thicker walls will yield less low frequency isolation. Also, these were just first renderings. He hasn't finished with the actual final design and BOM yet!

what Stuart is getting to: 2" 67.6 Hz 8" 33.8 Hz (based on 1/2" and 5/8" glass panes) the higher resonance will be a problem because its much more audible and this doesn't even account for 20 log(msf)–34db and the coincidence dip.

2 2x4's mounted in a 10" space (not counting the drywall) leaves 2" between the boards.

No it does not. It leaves a 3 inch separation between the frames, 10" of air gap, and the entire wall is 11 1/4" thick. If your designer thinks that standard 2x4's actually measure 2 inches by 4 inches, then you have a much bigger problem than you ever imagined! 2 x 4's actually measure about 1 1/2" x 3 1/2", at best, and often even less than that. So if you have a decoupled 10 inch wall made from 2x4s, then you MUST have a 3" physical gap between the frames. It cannot possibly be 2". This does not consider the drywall, which adds 5/8 to each side, thus increasing the total wall thickness to 11 1/4". Like this: But that is NOT what your diagrams show! In your case, the entire wall width is 10", including drywall, which adds 5/8 on the outer faces of both frames. Therefore, you MUST have a physical separation of 1 3/4" between the frames. It cannot possibly be 2". Like this: Either way, your separation between frames cannot be 2 inches. No way. It can either be 3" or 1 3/4". And either way, your air gap also cannot possibly be 2 inches. It can either be 10" or 8 1/2". I get the distinct impression that there is a LOT of confusion about what you guys are actually designing and building! The fact that your designer does not know the true dimensions of lumber is more than just a little bit worrying. What else does he not know about building? Personally, I would not use either of those methods for a vocal booth. I'd build the inner leaf inside-out, narrow the separation to 1/2", thus leaving a 4" air gap, and gaining a whole 8 inches of space inside the booth, which I could then use for treatment... Anyway, getting back to the original point: You do not have 2" of air gap for your window: you have at least 8 1/2" and maybe even 10". So you have enough gap for decent isolation with 1/2" laminate glass, without any doubt. You never needed 3/4".

As for the outer walls having drywall, yeah they will. I don't see why it will be a problem or how having thicker walls will yield less low frequency isolation.

Then you might want to look into the issue of the major problems that occur when you build a 3-leaf wall. Contrary to popular belief, adding a third leaf to a wall does not improve the isolation: all other things being equal, it WILL reduce isolation in the lower end of the spectrum, simply because you have re-tuned the wall, thus moving the entire TL curve UP the spectrum, which obviously implies that the resonance dip is now well into the audible spectrum. Therefore, you have reduced isolation on the low end, NOT increased it. If you put a decoupled 2-leaf wall next to another decoupled 2-leaf wall, then you have the even WORSE case of a 4-leaf wall! :shock:

Well, I know the back outer booth wall is there because there is a window along that back wall.

Thus, you have created a 3-leaf system with that window. Bad idea. Isolation out through that window will be bad in the low end of the spectrum, and ESPECIALLY if the glass in that window is just ordinary thin window glass.

The two side outer booth walls we have actually been thinking about removing because it might of been over kill for what we are isolating.

Actually, it is under-kill, not over-kill. If you have those wall there, then you have triple-leaf systems, and thus reduced isolation. It is costing you roughly 20 decibels of isolation, Only by removing those walls can you get good isolation. Maybe this diagram will help you to understand: Right now, your situation is the third from the left, rated STC-40. Take out the offending two leaves from both walls, and magically you get STC-57. Yes, that's right: by TAKING OUT those two sheets that are causing your 3rd and 4th leaf, you IMPROVE your isolation by 17 decibels... You mean your designer didn't know this? And he's an expert in acoustics? :shock: Did he tell you what that equation means? - Stuart -

what Stuart is getting to: 2" 67.6 Hz 8" 33.8 Hz

Exactly! Thank you, Glenn! :) Which of course implies that the 2" example won't have decent isolation until at around 140 Hz, while the 8" example has good isolation at 70 Hz, an entire octave lower. And that doesn't even consider the 3-leaf issue (or 4-leaf). - Stuart -

Stu, can't really quote all that cuz I'm on my iPhone. But we were never using drywall on the insides of the beams. Just on the outsides. That last picture you posted now makes me understand what you were talking about with leafs and all of that. Our actual design is the stc 57 one, but with 3/4" drywall, not 5/8". And again, the drawings are only concept drawings from the first stage of design.

But we were never using drywall on the insides of the beams. Just on the outsides.

I think you still don't understand! That isn't the issue at all. Your booth will consist of two leaves, exactly like the "STC-57" image. BUT YOU ARE PLACING IT NEXT TO AN EXISTING 2-LEAF WALL!!!!!! Which means that you are now back to the STC-40 situation: a 4-leaf wall... your 2-leaf booth, plus the existing 2-leaf wall, makes a 4-leaf wall... What you aren't getting here is that the booth is not an isolated thing, floating in outer space, thousands of miles from anything else. It is not an island. It interacts with its surroundings. You have your booth walls located right next to ANOTHER wall, and that is what wrecks your isolation. Placing two MSM walls in proximity re-tunes BOTH of them: they now act as if they were one single 4-leaf wall, tuned to a much higher resonant frequency. Thus, you lose isolation. Once again, these are very simple things that an acoustic designer should be very much aware of, and should take into consideration in his design. This is basic acoustics 101! The fact that you guys are not even getting this basic stuff right, leads me to wonder what else you are not getting right. I would strongly suggest that you should not build anything yet, nor even buy any materials, until you have your design fully thought through, and carefully checked to make sure that it at least complies with basic acoustic principles. Right now you are wasting a lot of space in that booth, and you haven't even shown the treatment that you will need to put in there! Right now, your booth is only 3 feet wide. By the time you put the necessary treatment in there, it is going to be down pretty close to 2 feet!!!! Have you considered that? I hope you only ever plan to record very skinny singers! (And no claustrophobic ones!) :) Standing in there is going to be very uncomfortable: 2 feet is barely shoulder width for most adults. How are you going to get a person, a mic stand, and a music stand in there? And even if you can, do you really expect the talent to perform with inspiration and gusto, in such a minute space. Plus, being that small, it will sound like crap no matter how you treat it. Your only two choices are: don't treat it and have honky thunky crap, or do treat it and have dead crap. But it is crap either way... On the other hand, if you build it correctly, the way I mentioned, you'd have about DOUBLE the space inside, nearly 4 feet, without even changing the exterior dimensions. And I'd change those, too, if I were designing that. It just doesn't make much sense at all like it is. So if you want my suggestion (you didn't ask, but I'll give it anyway :) ), I'd get that whole thing re-designed by someone who actually does know a bit about acoustics, and actually can identify (and use!) the equation I gave you above. Right now you are wasting a stack of extra money on materials you don't need, and wasting a stack of space that you DO need, all to get a minuscule booth that does not isolate well, sounds like the interior of a large pillow, and won't work acoustically anyway! Do yourself a favor: design it right, save all of that money that you don't need to waste, and end up with a booth that actually is usable. Sorry to be so blunt, but I'm just calling it the way I see it. If you don't want any more comments from me on your thread, then just say so and I'll shut up. - Stuart -

Yeah, he is closer to completing the design. We did end up getting rid the side and rear walls. He started with a wall inside a wall concept because that's how he built his. But he realized I don't have anything going on around my spot. At his spot, there can be up to 4 bands playing in the different rehearsal rooms. I don't have all of that, so he made a much simpler design. I just talked to him 2 hours ago. He says the inside will end up being 3'-10" wide, which is wider than the recording space I have now. Here is the layout of the room:

Why not turn that around and have the desk centered on the wall with window A? This will put the entry door more into the "live" space and give you some room for angled treatments on the desk side. You might skip a booth and go with tall gobos with windows. By 3/4 you mean 2 layers of 3/8 drywall? Versus say adding 5/8 and getting it to an inch? Lose the futon and go with a small love seat or chairs.

gullfo wrote:

Why not turn that around and have the desk centered on the wall with window A? This will put the entry door more into the "live" space and give you some room for angled treatments on the desk side. You might skip a booth and go with tall gobos with windows. By 3/4 you mean 2 layers of 3/8 drywall? Versus say adding 5/8 and getting it to an inch? Lose the futon and go with a small love seat or chairs.

We are losing the futon. The futon is what was causing us to have to reduce the inside of the booth width. But I sat on the thing last week and that thing sucks to sit on. :lol: So last week I decided to get rid of it and probably go with a small black leather love seat. As for the build of the drywall, I have no idea! I can't put the booth at the other end because that window is where my a/c goes. The other window is a small "hatch" style window and cannot fit an air conditioner. A central air unit is out of the budget!