Blocking Out Window..

[Prof.]

I have a 5'x4' window on the back wall of my theatre..which is about 50% of the wall area..
At the moment I have a blockout blind and a heavy black open weave curtain material over the window..

I'm thinking of removing both and replacing them with two removable panels..
These panels will just be timber framed with some type of "Insulation" material fitted and covered with a face material of some sort..

I have a bit of a dilemma with the "materials" needed for this set up, because the panels have to perform in three different ways..

1. It has to provide total blockout for the room.
2. It has to act as an insulator to keep outside heat from getting into the room.
3. It needs to be effective as an acoustic panel..Probably partly reflective and partly absorbent..

Can anyone recommend what would be the best type of insulation material to use, and what type of covering should the panels have.?

[bpape]

Build a plug and fill with 4" 703 or mineral wool. Face the absorbant with FSK facing. Build the framing such that there is a lip on it so when it slides into the window opening, the lip extends out past the opening on all 4 sides and use weatherstrippling on the back side of this lip.

This gives good heat/cold insulation, complete light control, good bass control, but somewhat reflective at mid and high frequencies.

Bryan

[Prof.]

Thanks Bryan...That's an excellent idea with the lip all around the perimeter..I was wondering how i could make a timber frame fit light tight inside the window frame..

So 4" of 703 (or our equivalent) will cover all the requirements..that's good news...it just so happens that the window recess is 4" deep!

Just one thing..I have some rockwool batts that will do the job, but they don't have a FSK facing..
Would just fitting some thin poster board to the face of the frame, be as effective?

[salvasol]

Prof. wrote:

I have a 5'x4' window on the back wall of my theatre...

This is what I did: I build a sliding door??? ... you can see the picture below. ...
i used 3/4 MDF, painted and because I had some accoustic carpet left overs; I cut some rectangular pieces and glued them to the boards



This helps with the heat/cold ... room is almost blacked out (there is a small gap, but not to much light) and I think I have a reflective/absorvant area there

But what Brian suggested seems a good idea ...

[Prof.]

salvasol wrote:

This is what I did: I build a sliding door???

That was what I thought originally of doing, but there isn't enough room to slide the panel to the side, and gain full access to the window..
I think the plug idea will work well, if I can find a similar material to the FSK facing, to place over the frame and to cover the rockwool..

[bpape]

Very thin posterboard could work OK. I'd prefer something thinner to give a better membrane effect and broaden the absorbtion hump. Maybe some heavy postal paper or butcher paper?

Bryan

[Prof.]

Ok..thanks, I'll look into what's available here in the thinner paper..

[Prof.]

Well, I've found a glass wool material here called "Supertel BPF"..and it comes in 50mm. thick sheets..
This is the same material I've used previously for the bass traps (OC703 equivalent) except it has a thin black paper face on it..
It's probably similar to your FSK facing, only black in colour and hopefully should work well for the back window covering..

I'll be adding an additional layer of the unfaced material to give me a total thickness of 100mm..

[Prof.]

Well I started making the back window plug last week..
It took two weeks for the fibreglass sheets to arrive.
I used 120mm. wide pine so there was enough overhang from the widow frame to fit a lip around the perimeter..

I decided to make it in one piece instead of two, so it could be pulled out as a complete unit to access the widow..





The frame being painted.


Frame is fitted to window and the Supertel BPF placed in position..

The facing is actually black, but the flash has washed it out..
The window plug will be covered with black open weave curtains, so there is no need to do any other covering of the plug..

The end result..A noticeable improvement in voice clarity..I heard words that had always been a bit masked..
Surround sound also became a bit cleaner and clearer, with little subtleties that had not been distinguishable previously..
All in all..a worthwhile modification..

[bpape]

Nice job

Bryan

[Prof.]

Thanks Bryan...and your window plug idea worked out well..It makes a nice tight seal..