John Sayers' Recording Studio Design Forum

If this isn't the best forum for this issue, if you know of any that would be more appropriate, I'd appreciate the input.

I'm installing my window soon into a home studio we built here in the Salt Lake City Utah area. The opening for the window is 3 feet by 5 feet. There will be two panes of glass with an 8 inch gap between them.

I know that the ideal would be to get two sheets of glass that are both laminante. Each sheet being a different thickness.

Unfortunately the only glass company I've found that can get me laminate, can only get it in one size. So my question is, if I settle for second best, which timing and money might demand. What's the best way to do it, and how much will I loose as far as sound loss. My budget is $400 or less for both sheets of glass. And would love to keep it under $300, but want it right more then anything.

I have 3 options.

1. Pick two sheets of laminate glass that are the same thickness (they are thin I think about 1/8 or 3/16 total thickness)
2. Pick up one sheet of Laminate glass and one sheet of standard glass that is thicker, say 1/4"
3. Pick up two pieces of standard glass that are each a differnt thickness say 3/16" and 1/4".

Any thoughts or comments as to what would work best and offer the best sound isolation in compared to the desired two sheets of varying thickness laminate would be appreciated.

Also, some side questions if anyone wants to chip in....

What do I need to use to isolate the glass from the windwo frame? Do I use a weather strip, if so what kind? Or do I use some kind of rubber or neoprene (I have some neoprene, but it's only as thick as a mouse pad will that work?) And how thick should it be? Also, do I caulk either side with Accoustic or silicon caulk?

Thanks in advance for the help,

Greg

Have you seen this thread and this thread?

Do a boolean search on this site... Use keywords "laminate glass," be sure to activate the "Search for all terms," and behold all the great info.

--Keith

Greg,

Not only should the 2 pieces of glass be different thicknesses - but the smaller of the 2 should equal the mass on the wall - and the next piece should be thicker than that piece.

Rod

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Ignore the man behind the curtain........

You know I had done a search for glass and window. Never thought to search for laminate glass, should have though since glass just pulled up a little of everything.

Sounds like the lamniate is probably the way to go even if it is the same thickness.

Also, I had found the SEA college stuff, but I didn't get enough info there as to how to float the window in the frame, i.e. caulk or not to caulk, rubber vs window weather striping etc.

Thus I had asked again. I'll keep doing some more searches though with your tips.

Thanks again,

Greg

An 8" gap with that thin glass won't give very good results, especially at lower frequencies - with 3/16" and 1/4" panes of float plate, you'd see about STC 45 but the TL @ 50 hZ would only be around 15 dB at best.

Laminated glass of the SAME thickness would improve the low end by probably 4-5 dB, due to Constrained Layer Damping effect (same as Green Glue for wallboard) - but THINNER laminated glass would negate any gains, and likely cost more.

Also, larger glasses (like 3x5 feet) have worse TL than smaller, so this is a trade-off situation.

Using 1/4" and 3/8 instead (float plate) would improve the low end by about 5 dB... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

OK, I misunderstood. The laminate glass that I can get readily here is 1/4" not 1/8th. They had said 1/8th meaning per side of the laminate.

With that correction, if I had two sheets of 1/4 inch laminate glass I'd be doing fairly well wouldn't I? Even with them being 3x5' sheets with an 8 inch gap?

How much better off is the 1/2" laminate on one side, as the 1/4 laminate is already 70 lbs, I don't think I want to try and lift into spot a 155 lb slab of glass if I don't have to. So if two 1/4" sheets will work well, and better then plate glass I think that's my best option? Unless someone convinces me to try and find another size to go with it?

Greg

Greg, Rod brought up a point I'd missed; in order for your window to not be the weak spot in your wall, the glass needs to have at least the same mass as the wallboard in each leaf of the wall - glass weighs about 3.5 times what gypsum weighs, so we generally recommend at least 1/3 as thick glass as the TOTAL gypsum for each side of a wall. This means that if you have double 5/8" gypsum each side of a wall, then each side's glass should be at least 1/3 of 1-1/4 inches, or 0.4 inches. In practice, using 3/8 for one side and 1/2" for the other, properly sealed, etc, will keep your window from being a big "hole in the wall".

Less than that will NOT prevent the window from weakening the wall, no matter HOW well you seal it.

Laminated glass tends to give better results at LOW frequencies than plate due to the CLD effect - but mids still need that thickness and air gap in order to "keep up" -

So NO, I can't recommend using only 1/4" glass of ANY type without feeling like I'm letting you down.

BTW, that weight seems a bit high; normal plate glass runs 161 pounds per cubic foot, which comes out to 100 pounds for a 1/2" thick 3' x 5' glass. So 1/4" lami glass should only weigh a bit over half that??!?

Also, you never mentioned what your wall construction is - can you either describe or post a sketch or pic? Thanks... Steve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Thanks for reminding me I hadn't described the studio. There are two rooms, one is 12 X 14, it's the live room. The other is 12 x 18 feet it's the control room.

The room will be used mainly for tracking vocals and some piano and sequencing work will be done as well. So it's more of a home project studio then a large production studio. We won't expect to be doing drums or electric guitar type of work. But will do some choral recording, i.e. 2-8 people at a time. The glass is there mostly so the director can stand in the live room and hear the recorded sound rather then the live sound, while still directing still be visible to direct.

As well the control room doubles as a home theater. So we'd like it to be sound proof enough that if we are working or watching a movie in the control room, and someone is playing the keyboard or tracking in the live room we don't hear them much if at all. But it's a project studio, so we don't need to break the bank either.

The build of the walls. It's very unique. The control room is actually an addition to the house. So the layers go like this....

Live room side... 1/2" drywall nailed to 2x4 studs with insulation. Other side of studs is a layer of 1/2" plywood and a brick wall. Then there is a 1" gap between that wall and the control room wall.

Then the Control room is a 2x4 insulated wall with 1/2" drywall. The total thickness of the overall wall is about 12-14". A Hall way with a 90 degree bend connects the rooms. There are 3 doors as well, one in the hall, one on each room.

Currently where the window is going to be I threw up some painted 5/8" drywall and framed it in like you might a window. Used a little caulk and some trim molding to mount it in place.

As of now, that is sufficient enough for our current needs as far as sound proofing goes. Everyone that's come by is impressed at how sound proof it is. And in the few recording sessions we did it with the live room door open, even then it was quiet enough with no noticeable bleed.

For our purpose, I don't think we need glass that is going to stop all bass bleed, or something production studio quality. This is just a home project studio with a $400 budget, unfortunately that's the price of on 1/2" laminate side. But currently with just those two sheets of 5/8" 3x5 drywall it's served us good enough. If I can match or beat the sound proofing of those two sheets of drywall, for $400, we'd be thrilled. Maybe someday we'll need more, but for now, it's enough.

So for our needs and set up... budget being a factor....

My options are
Option 1 - two 1/4" laminate sheets
Option 2 - one 1/4" laminate and one 1/2" plate
Option 3 - Or one 3/8 plate and one 1/2" plate

So using Rod's 1/3 rule, the 1/4 inch glass would be equal to the 3/4" drywall so it should perform as well if not better then the 5/8" drywall correct?

Needless to say I'm still confused as to what might work best overall, as sounds like the plate glass might be even better since it's thicker, although sounds like the laminate helps with the bass,but the thicker plate glass will do more for the mids and highs, which is more what we encouter. So does that mean options 2 and 3 are my best bet then?

Thanks,

Greg

Yeah, I'd go for option 2 - with the heavier glass placed on the wall leaf that has the heaviest mass, if they're different... Steve

_________________
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Thanks so much for the help... sorry I hadn't explained my needs better upfront.... live and learn I guess... thanks again for the advice....

One last question.... any thoughts on how to suspend the window? I've heard so many things for what material to use.... seems like most people lined the edges with weather stripping so as to let the window float and not touch the wood. Is this the best method, or should I lay some thing rubber neoprene down. Or should I do both?

Thanks,

Greg

Greg, you're welcome; now, if you could do ME a favor and follow the top thread in this forum, including the part about editing your profile to include a location? It's easier that way than scrolling back thru a few hundred posts to see where someone's from when they're asking about area-specific things, etc -

Also, that same top thread will refer you to the REFERENCE section, and if you click on THAT link the info you're looking for is the 13th link from the top of the page - with sketches and everything.

If you still have questions after reading through that info, c'mon back and I'll see what I can do... STeve

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Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Thanks for the reminder, I had read the Top post.... must have gotten distracted laughing at the follow up posts though... and forgotten to edit my location.

As to the link... I had actually gone to that link 3 or 4 times on my own, as well as the link to the SAE college dozens of times before it was mentioned above. Both links left me wanting more info.... turns out this time after going back to your link, I realized that it's a link to the 2nd page of the posts. I assumed I had arrived at the correct place since there was a picture and some instructions, but it wasn't very descript as to the window, it talked much more about the wall construction.

This time however, I realized that the link is to the 2nd page of the topic, when I realized that and ventured back to the first page, then I found the picture I was looking for, that showed how to build install and seal the window in. Lots of detail there.... thanks so much for the reference.

My appologies for not finding it sooner, mia culpa for not paying more attention to the fact that there were more posts on the page before. Thought I'd let you know though since I'm sure there will be more crazy late nighters like me.

Thanks again for the help.....

Greg

Dear Greggomer:

Thanks for the post just above this. I have goen through similar exercises with different sites/threads etc. It's good to read about other people's experiences and it helps other people in their research here and on other sites.

I've got the tshirt too:
Andre

how r you doing knightfly... PLease would you let me know where is this LINK located, I cannot find it, I need a very clear reference to mount, install and seal my glasses,..
THANKS

digging up a 6 years old topic, eh. Steve (knightfly) isn't active here since a few years (sadly, I miss the man.. sniff)
The reference link, ah.
viewtopic.php?f=2&t=2125

duh, it's a sticky. there's plenty o' info on this forum on how to, exactly, mount glass. have you bought Rod's book yet? it's in there too. If ye don't know about glass installation, ask a local dealer to do it for you and tell'm about closing up the gaps for sound isolation. (!).

topic closed.