DIY acoustic blackout curtains

[Ben M]

Hi folks
Hoping to tap into the T’rock acoustics brains trust on this one.

I’m planning to diy a bunch of temporary blackout acoustic curtains for a large space with 10 windows. Windows are 101cm wide x 140cm high. These will be temporarily hung over the windows to help black out the space and to provide “some” sound absorbency. Sort of two birds with one stone….

I was planning to sew the curtains into a sort of ‘pocket’ (similar to a doona cover) into which the absorbent material would be placed.

I’m thinking the absorbent material should be around 30mm thick as to not bulk them out too much. But hoping to get something that is fairly broadband…?

Does anyone have some advise on absorbent fluffy stuff that will do a good job for this idea?

Hoping to find something that is at least 101cm wide so I can use one piece inside (so probably 120cm x on a roll).

Also something that’s not semi rigid so it can be stored in a compact way.

Many thanks in advance for suggestions.

[Senad]

Hi Ben,
I haven't used it, but some people have been talking about the PolyMax stuff lately.
THey seem to have it in 25mm thickness, LD, MD, HD (low/mid/high density)
Looks like it comes in 2400x1200 sheets, and they say they can supply in custom sizes.
you could probably get them to supply you a roll in the width you need, then you just cut the lengths up.
Hope it helps.

[Paul Maybury]

Hi, I have had good results using regular theatre curtain, the heavier the better.
Hang it out from the wall as far as you can. The more heavily draped it is, the better the broadband absorption.
Cheers,
Paul

[gigpiglet]

hey ben
i had to once do some temp sound proofing of a room for a concert in sydney city
we did MDF boards (at full sheet size) with absorbant backing, screwed up over the windows
then drapes all around (groud support - easy, temporary, and easy to hire)

happy to talk directly if you would like any thoughts/ ideas

[Kurt]

I have 18mm MDF screwed to the frame of my spare bedroom window, not soundproof but easy to remove and certainly better than a window for stopping drums annoying the neighbours too badly.

[Senad]

Solid sheets are the quickest (and probably better) solution, but maybe he'd like to be able to just pull the drapes open/closed at any time..
Is this why you're going with drapes, Ben?

[Ben M]

Thanks for the replies guys.

I'm not necessarily looking to sound proof this country hall, just wanting to temporarily (and on regular occasions) blackout and cut some verb/echo. Then take down and store in-between shows/screenings. Doesn't have to be beautiful, but also not an eye-sore.

Thinking more down the lines of the polymax covered in black drape…weighted at the base with the sheet overshooting the window width and height. So mostly trying to take advantage of the temporary nature of the blacking out and adding a bigger absorbing component.
Tell me straight..Is this going to look freakin ugly?

I did have panels in mind initially but have since gone off that due to storage..cost..and..

Any creative ideas in this area? Anyone been down this road?
Any further opinions on absorbent material that is thin for it's broad’er’band abs. potential? Polymax could be the go!
cheers

[Senad]

POlymax is pretty expensive and any polyester insulation that is thin enough (they usually come in rolls) will be better than just the curtains on their own... Also, the lower density of the insulation, the more flexible it will be inside the curtains, but less effective the lower you go in the freq spectrum, obviously..

[Kurt]

I wonder if a standard rubber backed block out curtain wouldn't be more effective than thin polyester? The ones in our lounge room certainly do cut down outside noise a bit.

[gigpiglet]

in that case ben
id suggest a double layer of regular (easy to hire) theatre black

by double, i mean instead of tying to the top bar, drape it over the top bar.
so if its 3m high, you need 6m drop drapes.

i have done that to "build" conference/ performance rooms in halls, and works pretty damn well.

[Ben M]

in that case ben
id suggest a double layer of regular (easy to hire) theatre black

by double, i mean instead of tying to the top bar, drape it over the top bar.
so if its 3m high, you need 6m drop drapes.

i have done that to "build" conference/ performance rooms in halls, and works pretty damn well.

Thanks G.
Trying to have something available for regular shows. Regularly hiring theatre drapes is not easy from my location..and regular hire costs for drapes isn't built into these shows.
I priced theatre drapes to buy and the cost was enormous of course.
I have around $2k budget to make something temp. that can be used approx once a month and then removed.
Maybe I should make a prototype of what I'm thinking to see how fugly it would be...

[Kurt]

What about curtains and a Magnetite style faux double glazing?

*I have no idea what sheets of clear acrylic cost.

[Ben M]

Hey Kurt, I appreciate the comments but I'm not attempting to sound proof the space from noise coming in or going out.. as mentioned above. Purely blackout and treatment for absorption to soak up the verb/echo.

So far my thoughts are for cloth covered 25mm sound absorption sheets overshooting the window openings.

cheers

[graemeh]

I got some black quilted material from our local Spotlight store to make a cover for the piano. It may be worth having a look there. Not expensive, about 5mm thick and 1.5m or so wide, comes on a roll - you just tell them how much you need.

[Drumstruck]

Looking at my gobos gave me an idea.....

3"x2" timber for the frames with:
- perforated masonite (inset) on one side
- unperforated masonite (inset) on the other side
- batts inside
- spray paint the outside your choice of colour
- add castors to one side for roll-in / roll-out

With this you have:
- a reflective side and an absorbtive side
- fairly lightweight
- can easily be touched up if they get scuffed
- can lean against a wall / window or be affixed with straps

Cheap - just a bit of cutting / screwing / painting.

[Ben M]

Looking at my gobos gave me an idea.....

3"x2" timber for the frames with:
- perforated masonite (inset) on one side
- unperforated masonite (inset) on the other side
- batts inside
- spray paint the outside your choice of colour
- add castors to one side for roll-in / roll-out

With this you have:
- a reflective side and an absorbtive side
- fairly lightweight
- can easily be touched up if they get scuffed
- can lean against a wall / window or be affixed with straps

Cheap - just a bit of cutting / screwing / painting.

I did have panels in mind initially but have since gone off that due to storage..cost..and..

As mentioned, I've already been down the 'panel' route. It would've been my preferred way to go... Simply place panels over the windows, job done!
Storing/transporting 10-14 panels is never an easy task. Plus I priced them out to $3300 (the way I'd do them).

[Drumstruck]

Scope / Schedule / Cost - one compromises the other.

[The Tasmanian]

Hey Ben,
If you can get hold of thick wool to make curtains, and bunch them so that they are 4:1 ratio IE: - 4m wide bunched up to to cover a 1m wide curtain, and all should work out fine and eliminate the problem.
The folds will soak up all of the reverberant info.
This works surprisingly well. Easy to pack up and store.
Wool is also better for fire.

[gigpiglet]

oh chris raises a valid point..
if its a commercial project/ space
may need to be fire retarded and certified.....

[Ben M]

Yes heavy black theatre drapes would be great. Perhaps over my budget still.
I have Molton and velvet theatre drapes but I'm very hesitant to cut them up as they are useful for a lot of other duties.
While I'm in Sydney this week I'll be doing some searching and pricing of different options.

I appreciate the replies.

Cheers

[tony]

Imported theatre fabrics in Victoria is where we end up sorcing a lot of our fabrics for shows these days.

[The Tasmanian]

Ben, I've been thinking more about if I had to do this on a very tiny budget.
How about thick woolen blankets (from vinnies) with black cotton covered/stitched over them, hiding the vinnies purchase.
Your small window size means 2 normal double bed blankets - stitched together & on their side would be perfect giving you the 4:1 fold.
Wool and cotton both being good for fire.
Another option would be those grey packing blankets covered with cotton.
Let us know what you end up doing.
Best of luck.

[Ben M]

Great thinking Chris.
Budget friendly and quickly achievable.

[simonstav]

Hey Ben,

I have been thinking about this as I am looking for a similar solution for providing some roller door isolation in both my workshop and also my warehouse. The warehouse I may go with Lotus doors cause I want some substantial isolation but need something more economical for the workshop.

A live music venue down the coast used to have really heavy wetsuit material with 400% gathering that they used along windows for when the band played in the bistro at night. I seem to remember this being somewhat effective. I may give this a go with my workshop and see how it pans out. Probably about 10mm thick and on a runner track.