Window and Door question.

princeplanet · Apr 12, 2020 4:58 am

Hi, I'm building a sound studio on the top floor of an office building and because it will be a "room within a room" design (for soundproofing), the inner dimensions will shrink a fair bit. So, first question, Is there a minimum height regulation for the doors? I have space for a 1940mm high door. Is that OK?

Next question is about windows - I need a large internal window (ie, not exposed to weather) to be 30mm thick! Now,, I have all these 10mm lam windows that I'd like to re purpose for this, by having 3 panes back to back, mounted in a purpose built heavy duty frame. Can this be done? Or will there be vibration issues, or condensation issues? Some of yu will be thinking that I should have gaps between the panes, but because I will have 2 such windows in separate boxes mounted in a double wall with an air gap between walls (ie one window per wall), then that gap (300mm) is the ONLY gap I should have. If you understand acoustic theory there is a Law which warns us not to have more than 2 "leaves" (wall or window) and that a 3. or 4th wall or pane will create a 3 leaf effect which, due to resonance, actually makes the sound isolation WORSE!

Sounds counter intuitive, I know, but trust me, it's a fact. Even small gaps of say 1mm between panes is enough to ruin the sound isolation as this creates a thin resonating channel. Multiple tiny gaps are even worse. So I need 30mm in one window and 15mm in the other, 300mm apart. No ifs, or buts. This is the expensive advice from the Acoustic Engineer. But he doesn't know if 3 panes can be placed in a frame back to back. I called a handful of glaziers and they couldn't tell me much either. Any thoughts out there? Obviously one could sandwich thin acrylic sheets between panes, like they do in the laminating process, but it needs to be heat treated at the factory, and we couldn't get a large 30mm lam window up the stairs.

building-expert · Apr 12, 2020 9:32 am

If your job is important to you then you should get a sound engineer to assist you

princeplanet · Apr 12, 2020 2:46 pm

I have an acoustic engineer, and an architect, and an SE. None have responded answer to my questions posted above, which is why I asked here. Either they don't know, are are taking too long to reply, under the current circumstances...

alexp79 · Apr 13, 2020 5:06 pm

what stops you from just getting a triple glazed window?

MClark · Apr 13, 2020 8:30 pm

I cannot help but I just say I'm pretty interested in the build. Flick some pics once she is done

princeplanet · Apr 13, 2020 11:45 pm

alexp79

what stops you from just getting a triple glazed window?

Triple glazed would mean having a gap between the panes. With gaps, the science will tell you to have no more than one gap. I need a 30mm window in one wall, them a 15mm window in the second (decoupled) wall with a gap < 200mm. Having extra little gaps creates separate resonances which actually amplify the sound at certain frequencies. Not good...

ECOECO · Apr 21, 2020 1:52 pm

princeplanet

Hi, I'm building a sound studio on the top floor of an office building and because it will be a "room within a room" design (for soundproofing), the inner dimensions will shrink a fair bit. So, first question, Is there a minimum height regulation for the doors? I have space for a 1940mm high door. Is that OK?

Next question is about windows - I need a large internal window (ie, not exposed to weather) to be 30mm thick! Now,, I have all these 10mm lam windows that I'd like to re purpose for this, by having 3 panes back to back, mounted in a purpose built heavy duty frame. Can this be done? Or will there be vibration issues, or condensation issues? Some of yu will be thinking that I should have gaps between the panes, but because I will have 2 such windows in separate boxes mounted in a double wall with an air gap between walls (ie one window per wall), then that gap (300mm) is the ONLY gap I should have. If you understand acoustic theory there is a Law which warns us not to have more than 2 "leaves" (wall or window) and that a 3. or 4th wall or pane will create a 3 leaf effect which, due to resonance, actually makes the sound isolation WORSE!

Sounds counter intuitive, I know, but trust me, it's a fact. Even small gaps of say 1mm between panes is enough to ruin the sound isolation as this creates a thin resonating channel. Multiple tiny gaps are even worse. So I need 30mm in one window and 15mm in the other, 300mm apart. No ifs, or buts. This is the expensive advice from the Acoustic Engineer. But he doesn't know if 3 panes can be placed in a frame back to back. I called a handful of glaziers and they couldn't tell me much either. Any thoughts out there? Obviously one could sandwich thin acrylic sheets between panes, like they do in the laminating process, but it needs to be heat treated at the factory, and we couldn't get a large 30mm lam window up the stairs.

What level of attenuation are you trying to achieve?

princeplanet · Apr 21, 2020 2:38 pm

High 60's STC.

ECOECO · Apr 22, 2020 1:13 pm

That's a tough ask... and expensive... and yes 30mm thick glass would be the go...

Here's a site that emulates the noise and glazing - though it does not give an acoustic value for the windows.

https://www.pilkington.com/cmsapplications/soundsimulator4/Sound%20Simulator.html

Our standard awning window rates Rw35 and Rw39 with improved glazing, your needs are a long way off that. But having been in some recording studios they don't seem to have 30mm of glass (both panes). Unless you have a specific noise source that requires Rw/STC 60+ I would recommend you try your version of acoustic glazing. I understand that a 4 degree tilt vertically and horizontally in one pane reduces harmonics.