Glass or Plexiglass ???

[tpreager]

HI all,

I was hoping if anybody knew which is better to use for a window in-between the Control room & Live room. I plan to use 4'x8' sheet of either glass or plexiglass. I think the STC rating on glass is a little better than plexiglass, and that glass is more expensive. Has anybody used plexiglass with good results?

I'm hoping to use 2 paines of different thickness mounted to a wood frame but the glass/plexiglass won't touch the wood, it will be lined with weather stripping foam.

Also, I've read to put the thicker piece on the Live room side, but I've also read to put it on the control room side as well, any comments towards this?

Thanks!!
Tim

[Track Rat]

Plexi glass is going to be WAY inferior to glass as far as sound transmission. Glass is a lot denser which is what you want.

[tpreager]

Have you heard the difference between the two before?

What thickness would you recommend for glass? 1/4" & 5/8" ??

Tim

[Track Rat]

I'm using two pieces of double insulated glass (patio door replacement glass) which comes out to four pieces of glass. It works for me very well. I can't compare plexi vs real glass as I've never seen antone use it as a control room window. You can't by the physics though.

[Outlaws]

Just a side note:

I had heard that its good to angle them a slightly. ????

Like if you were looking at the side view it would be like this...

\ /



Is that true?

[tpreager]

I believe angling the windows doesn't do much for sound transmission, but what it does do is help reduce the glare on the window so that you can actually see through it

[James Argo]

Originally Posted by tpreager

I believe angling the windows doesn't do much for sound transmission, but what it does do is help reduce the glare on the window so that you can actually see through it

Not realy. It's just you need to avoid two parallel surfaces as much as possible, specialy with hard surfaces. They'll likely make broader standing wave between them. I'm not realy an expert on this subject, just sharing what I've heard to be true. In fact, I have a question regarding this issue. I'm about to install the glass between two rooms. I'm thinking of angling one of the window, while the other will stand vertical. Does anyone know where to put the angled (diagonal) one? Facing control room, or booth room? Thanks



Jaymz

[Innovations]

What counts is density so if you use plexi you would have to use much thicker anyway to get the same weight. Laminated glass also performs slightly better nonlaminated. It is also better to have the two panes not be the same thickness.

Total up the wieght per square foot on each side of the wall. That should be the weight per square foot for the glass on that side too.

Not havin the two panes be parallel is correct, but they could be out of parallel in the horizontal plane rather than the vertical. John Sayers likes to make studios using two pairs of sliding glass doors as both the entrance and view. Obviously those can't be slanted vertically.

Also the diagram shows the two panes mounted in the same frame. This allows the frame to be a nice single path for sound to transmit. have each pane in its own frame with a cover or caulk separating them.

[James Argo]

Thanks Innovations Yes, I am aware of the frame. Sorry for the quick drawing above Actualy I'm using two frame. The gap between is tight filled by thick rubber. The glasses would be 6mm on one side, and 9mm on the other side. Both would be gripped by thick rubber & special glue (I forgot...).


Jaymz

[tpreager]

Does it matter which side the thicker glass goes on? I've read that it's better to put the thicker glass on the wall that was more pounds-per-square-foot.

Also, does it matter which glass is angled? Should I angle both? or just the control room side?

[Son of Mixerman]

Angle both.
I put the thicker glass on the side where the highest load wil be. Usually the side where the instruments will be just because that where musicians are more likely to smack it. Also make sure that the side that is thickest is safety laminate.


SoMm

[tpreager]

Okay, sounds good, I think that's what I'll do. I'll be ordering the glass soon and installing it probably next week so I'll let you guys know how it goes!

any suggestions on thickness? 1/4" & 3/8" be allright?

[Innovations]

Yes the thicker glass should be on the side with the heavier sheathing. The reason is that otherwise the sound has a easy path to go throught the thin glass and then the thin wall.

As for the slanting, the decision is based on reflections. If the glass wall is parallel to the opposite wall of the tracking room then difinitely slant the glass of the tracking room so that it does not cause flutter echoes with the opposite wall. If slanting the glass on the control room side would have the glass pointing directly at the seated person at the console then don't slant it that way because you will be making it harder to create a reflection free zone.

If you are building the tracking room for a specific purpose you might want to look at the mic vs sound position and whether the glass provides a direct reflection from the one to the other. It reminds me of an experience I had with a studio when doing some audiobook recording. The room was normally used for stand-up voiceover recording and the slanted glass would deflect the sound down towards the floor. But for the audiobooks the narrator is usually seated (hours-long recording sessions) That changed the reflection off the glass right from the mouth to the mic. The solution was simply to change the seat/mic orientation so that it was diagonal across the room rather than facing the window.

[James Argo]

Thanks guys That was realy helpfull


Jaymz