Blocking sound from window using Rockwool - what density?

[coyotekells]

I want to build some "soft panels" (ie, enclosed by a pillow case type cover, not a hard frame).

These panels would snugly squeeze into the window frame in my project studio...

Main reason: BLOCK OUT STREET NOISE
reason b and c: block out HOT sun, extra acoustical absorbers


My question is, what do you expect the optimal DENSITY would be for blocking street noise?

I can't go very thick, so for something that is no more than 2" thick (as thin as 1" if you think that might work still) -- what is the best density?

Denser would be better for a panel so thin, right?

[avare]

To block sound you need mass and sealing. Fiberglass by itself does nothing.

Andre

[coyotekells]

Hmm.. by "block" I only meant "cut-down".. I have no stupid ideas that this would seal out the sound..

But you say it does NOTHING?? REALLY? Covering a closed glass window with 2" rockwool wouldn't lower the amount of external noise passing through?

[Weasel9992]

I'm sure what he means is that it won't block it; it will certainly cut down on some of the 1-4Khz stuff...voices, maybe shoes clicking on sidewalk or something. If you're looking to cut down on low end rumble from cars and stuff, that's a different story.

Frank

[dredbird]

From my looking into acoustical or sound-blocking curtains, I got the idea that thick, closely woven curtains in front of a layer of closed cell foam (like mousepad foam) would be worth trying.

Haven't tried it yet though ...

Otherwise, you could try to find some used theater curtain from a school, church or movie theater. That's aboot the thickest kind of curtain you'll find, I think.

[coyotekells]

Cool.. we're on the same page... I just used the wrong language ("block" is strong words!!)

To get the most mileage (ie cut down sound the most) should I be looking to do denser material (6 pcf) or more like 3 pcf

this is for 2" thick panels

[avare]

Insulation by itself is not an effective sound isolator. To give an idea of what what they do, do the following is from test data on 3" thick 2.8 lb/ft^3 insulation TL is 4 dB @ 125 Hz, then a straight line to 18 dB @ 5 kHz.

You can duplicate this effect to hear it with headphones and a a graphic equalizer. To hear the effect on low frequencies, you can be exaggerate the effect by turning the bass tone control down 6 dB.

Andre

[Studio Dweller]

You definitely need a layer of mass in addition to the insulation. There's some good info here for just what you're looking to do:

Soundproofing Windows

[Glenn Kuras]

Originally Posted by dredbird

From my looking into acoustical or sound-blocking curtains, I got the idea that thick, closely woven curtains in front of a layer of closed cell foam (like mousepad foam) would be worth trying.

Haven't tried it yet though ...

Otherwise, you could try to find some used theater curtain from a school, church or movie theater. That's aboot the thickest kind of curtain you'll find, I think.

Hate to say but there is no such thing as sound-blocking curtains or anything that really works.

Glenn

[dredbird]

Originally Posted by Glenn Kuras

Hate to say but there is no such thing as sound-blocking curtains or anything that really works.

Glenn

Why do you hate to say it? It's only true