Plexiglass-absortion coefficient

  • Thread starter Thread starter 87PRS
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Hello, Plex is along the lines of glass, which is a reflective material, not an absorbative. Although, as a flexible panel, it would, under the right circumstances, act as a panel absorber to a certain degree. Even used as a window, it is much more flexible than float glass. Your gyp board walls act as diaphramatic absorbers also, so figure in the walls and ceiling too. Although 2' x 4' seems rather small in the 2' dimension, I guess its all in the eye of the beholder. I have heard of people using plex, but be aware that plex scratches easily, so when cleaning, use a product called Novus 1, which is a plastics cleaner and anti static. It fogs over time also. And one other thing. Thickness of the plex is what determines its mass, which translates into its ability to resist vibratory transmission of sound. I would recommend, IF your choose to use plex, use AT LEAST 3/8" thick. Remember, sound transmits through material, not only by its lack of mass, but by its flexibility too. If you use (2) 1/4" plex panels, they can conduct vibration at the same resonance, so use two different thickness's. And frankly, given a choice, I would use Laminated glass. Or 3/8" to 1/2" float glass, as I think 1/4" plex will negate other soundproofing methods and techniques used in the iso walls.

Another thing to remember. A room designed for a certain STC, must have ALL the materials and construction designed and installed correctly in order for the assembly to act as a whole. Doors, jambs, thresholds, walls, ceilings, floors, windows, HVAC, design , construcion and installation, all have STC ratings in order for the designer to calculate how he will accomlish it. Any one of these items can totaly negate all other techniques and materials, IF not done correctly. Sound transmission by flanking, structural, airborn, or other means can waste thousands of dollars in construction time and marterials. So if absorption in plex is your only concern, I would recommend looking at your room construction as a whole first, not just the window. Of course, heres my disclaimer, I am no expert, this is just my .02.
fitZ:)
 
87PRS

Rick is correct,

I researched extensively and sought the advice here (about the plexiglass/glass issue.) I ended up using laminated glass (1/4" sheets - two 1/8 sheets laminated together) I put in two 1/4" sheets with an air gap (3"). And made sure I caulked very liberally to get a good seal.

Mine ran about $9.75 a sq ft.

larry
 
Thank you fitZ and Larry...that helps alot, and fitZ you sure sound like ya know what you're talking about, expert or not. I put a drawing here on the bbs at one time of the (shed) room I constucted, although I decided not to have an enclosed drum room and opted for the open space and Gobos, thought I'd be able to experiment with the drum sound better this way. I also have a 16X12 space in ther rear of building, which I call the shop, this could also be utilized at a later date (4x4 vocal booth?). My room is 16X20 with a control room in a corner at a approx. 55 degree angle front and four foot side wall to door I thought this would break up the squareness of the room, the ceiling has a deliberate slope of 2", all surfaces drywalled 3/8" with r13 (I'm in Florida) and caulked, silicone base every where I could squeeze it in haha I plan on doing 8 absorption panels with 2" 703 for wall treatment plus a 4x6 gobo, also be able to move them all around, I have the design from Ethan Winer and pretty much will stick to that, use some aurlex here and there for high/mid freqs and just experiment. First studio build, so your help is very much appreciated. BTW, I'm out in the woods here...literally. Thanks for responding, Ralph
 
Sorry Guys, i forgot...yes, I'm going with the glass. Thanks for all the info.
 
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