John Sayers' Recording Studio Design Forum Archive

Yes Pavatex is correct, the only other begriff I know is Weichfaserplatten which I believe is what Coop sells it under.

BriHar wrote:Yes Pavatex is correct, the only other begriff I know is Weichfaserplatten which I believe is what Coop sells it under.

OK - good to know, thanks!

I was thinking of using thin (3-4mm) MDF for mine - I saw some today that is normally used on door backs here in Turkey. After reading the thread I can't see how it could be worse than 6/12mm OSB...?

maybe too much mass ?

Bought mine by Zehnder Holzbau in Winti there they referred to it as weichfaserplatten

Hi all - just a quick question re acoustic hanger installation. John says "hangers should be ... spaced 6 to 8 inches apart". Is that measured from center to center of the panels, or from edge to edge ? With a panel that is 2.5" thick, that difference will affect how many panels I can hang in my space.

The spacing is roughly, not exact science. Just keep enough space between them so than hang freely.

I would think that more panels increases the absorption/diffusion effect, so I want to put as many panels into the space as I can, but I don't want to cross any line where they are too close together. Does anyone have a recommendation based on their experience ? 6" from center to center leaves 3.5" of air gap between panels. Is that enough ?

Depends what part of the room you are talking about. If you are talking about hangers under speaker soffits, then hang them close so you can get plenty in, with just a small gap between (surface to surface, maybe an inch). The idea is that they hang freely and do not touch each other, or anything else. But if you are talking about hangers across the rear wall or above a fabric ceiling, then that's a bit different: AFAIK, John recommends starting with one hanger at the mid point of the room, then dividing the gap distance in two and hanging another one there, then divide by two again and hang more there, etc, until you can't get any more in without them touching. The theory is that you are placing them at the peak half-wave point, then quarter wave point, then eighth-wave, etc.

- Stuart -

Stuart -- thanks for the reply. I am in fact talking about hanging them across the back of the room. I had not come across the recommendation to start in the middle and divide the gap in half until no more will fit without touching. Interesting. But that sounds like it would potentially result in panels being pretty close together, closer than 6 to 8 inches. Maybe as my next step I should figure out what the spacing would be if I start in the middle and divide, but stop when I get to a center to center distance of approx 7 inches.

Does anyone else have input on this approach ?

As far as I know, that 6" to 8" spacing, is center-to-center, not air gap.

We like to add a question on this topic
Is there a way to calculate on which frequency different sizes of board will work?
The size,mass and damping matters offcourse.

Whe found some flanking absorber on the internet based on a acoustic hanger close to the wall with damping on the back.
But again no calculations how to "tune" this type of absorber.
It is like a bit of voodoo for us

We have intrest in this type because we have not the space for the free hanging types.



Many thanx

Remy and Angelie

NOTE: We understand now that hanger are something for scooby doo and his friends because they do mysteries and no one knows the answer for sure. But how about the image we post? I guess rhat will remain a mysterie too.
PERHAPS we need to stick around for answers or else helmholtz resonators are the thing for us

Hi there "Remy & Angelie", and welcome to the forum!

It would probably be a good idea if you start your own thread, and provide all the details of where you are right now and what you need to do, including photos, diagrams, graphs, and descriptions. There's not enough information in your initial post to be able to help very much.

- Stuart -

Great thread!

Can someone tell me if the orientation of the hangers matters? What I mean; look at the backwall on the two drawings I attached. Which orientation works better? (Or isn't there a sound difference?)

Can someone tell me if the orientation of the hangers matters

There's not that much difference, the way I see it. At least, for randomly incident sound, which is mostly the issue at the back of the room, where these traps are typically used. I normally angle them a bit, towards the direct sound coming from the speakers, which is normally incident, and that angle also means that you can make the hangers a bit bigger, which helps.

- Stuart -