construction nearly complete, expect for the window.....

[pskjr]

hey all, it's been a while since i've been on here, but, construction is almost complete on the studio! plans changed, and i ended up scoring a spot in a barn, for free! only problem is the space isn't all that big, but hey, i'll take it for no overhead. so the studio will is split into two rooms, one live room, one control room. the live room is roughly 10'x14' with 8' ceilings. control room is about the same size, but has an open doorway that measures about 6' tall x 4-5' wide. i wanted to make it one room, but i'm sharing the space because it's being used for a media room for my church, and since there will be an opening i'll need to isolate the live room to reduce the noise as much as possible. all of the drywall is up, wall framed out and dry-walled, now ready to put the glass in for the window. we lucked out and found 3 sheets of glass big enough for a window, each about 1/2'' thick. i know most studios have two pieces of glass for the window, one at an angle, one straight up and down. now here's my question...

what is the reasoning behind having two pieces of glass? advantages? disadvantages to only using one sheet of glass? how much of an angle? which piece gets angled? always have been curious but never researched it. does the amount of space matter? is it worth it to put the pieces of glass up?

[JWL]

The advantage to 2 pieces of glass is that if properly implemented, it maintains a 2-leaf construction and can perform very well in terms of sound isolation.

A one-leaf system can work OK if there is adequate mass to the glass. But isolation is only as good as your weakest link. It depends on what else is happening in the room.

[Snarl 12/8]

I always thought that the angle thing was to reduce visual reflections and it didn't have anything to do with sound. 1/2" glass sounds like it'll really help stop sound. 2 sheets are better than one. You're also better off if the glass is tempered or plastic coated basically and if one piece is a different thickness than the other.

[Aquaman]

The glass is angled so sound doesn't come bouncing right back in your face. It's also angled so the area in between the two panes doesn't become a resonant chamber.

1/4" tempered safety glass (it has a laminated plastic sheet sandwiched in between two 1/8' panes, the same stuff they use in storefront windows) has better sound transmission damping than 1/2" plain glass, weighs and costs half as much, and you can throw chairs at it.

I put two 4'x6' panes in my place during construction - they cost a little under $100 apiece.

[JWL]

The glass is angled so sound doesn't come bouncing right back in your face.

Right on. Usually it is toward the floor in the recording space, but this can vary. If you have a reflective floor and an absorptive ceiling, it might make sense to aim the reflections upward toward the absorber.

It's also angled so the area in between the two panes doesn't become a resonant chamber.

Actually this is debatable. It's kind of an "old wives tale" for studio design. More recent testing shows that the best thing for iso is to maximize the airspace between the glass, which implies 2 flat surfaces as far from one another as possible.

That said, I'd probably still angle the glass downward a bit in the recording room, just to aim reflections somewhere other than right back out into the room, preferably toward absorption.

[pskjr]

all makes sense to me haha. thanks everyone for the responses.

[Snarl 12/8]

I read "glass" and "reflections" a long time ago and just assumed light reflections. Shoulda known it was sound in a discussion of control room glass. Learn something new every day.