Foil Absorbers?

[FriFlo]

I recently heard about foil-absorbers (german Folienabsorber), which seem to cover only a small range between 50 and 100 Hertz. I could buy them for serious money here:
http://www.acm-akustik.de/
Before having to spend so much money again I was wondering if I could build it myself. The principle is a special acoustic foil clamped over a wooden frame, filled with isolation and sealed from the back. Seems to follow the m-s-m principle. However, I cannot find much about these panels, and nothing about how to build them. Here in the forum I couldn't find anything about the existence of such absorbers, so I was wondering what they might be called in english?!
Here you can buy them (you must choose "Modular" - "Akustik Module" - "Folienabsorber"):
http://www.acm-akustik.de/
And this is some info on how they work:
http://www.baunetzwissen.de/standardart ... 47745.html

[FriFlo]

Oops! Suddenly, the reply I saw yesterday vanished ... Thanks for the answer to whoever gave it and merry christmas to you!
I wonder how it got deleted ...

[chrisuhf]

hi there

it was I who replied,
no problem, glad to share the info
just to reiterate in case you didnt get to save it before it was deleted
- they are called micro perforated absorbers (a kind of resonant absorber that works like a helmholtz resonator)
- Book 1 : acoustic absorbers and diffusers:theory, design and application by trevor j cox and peter D'antonio
- Book 2 : the master handbook of acoustics by F alton everest

however the admin / moderators of this site were seemingly not so glad about my new membership and first contributions

it seems that they have deleted both my posts and my account (I just re joined)

i guess that they didn't like me offering for sale, in another post, some acoustic treatments that I had made (using info from the books I recomended)

even though it says nowhere in the "forum rules" or "dont even think about posting before you read this" that offering items for sale is against the rules

good luck and merry christmas to you too

[Soundman2020]

i guess that they didn't like me offering for sale, in another post, some acoustic treatments that I had made

Right. I'm not sure why you would have expected a different response.

It is just plain good manners to request permission to use someone else's forum for your profit, before doing so. Offering your own acoustic products and services on the forum of a highly respected, world-renown acoustic designer simply smacks of trying to piggy-back on the success of others. You at least could have contacted John and asked him for permission to offer your products / services on his board. There are several large manufacturers of acoustic products who are welcome to post on the forum, precisely because they NEVER attempt to profit from it, and are only interested in helping out. There are even direct competitors of John, other studio designers, who are welcome to post here regularly for the same reason: they have the common courtesy to not try to compete with him.

even though it says nowhere in the "forum rules" or "dont even think about posting before you read this" that offering items for sale is against the rules

Well, that kind of goes without saying, don't you think? It sort of stands to reason that you should not jump on to someone else's marketing platform and attempt to promote your products over theirs, without even asking! If Pepsi starting promoting their drinks on a Coca-Cola web site, do you think they would last even five minutes?

however the admin / moderators of this site were seemingly not so glad about my new membership and first contributions

Your contributions are fine and most welcome. Your sales pitch and marketing promotion is not. If you'd like to contribute by offering your knowledge and know-how for free help to others, just like everyone else here, then that's excellent, and would be very much appreciated. But if you have products to sell, then it just stands to reason that you should ask John for his OK before doing that.


Merry Christmas, and happy New Year!

- Stuart -


FEBRUARY 19, 2013, EDITED TO ADD: Two months have now passed, and you have shown any sign at all of trying to help anyone. Not even a single additional post! That leaves your original motives crystal clear, I think: the sole intention was to sell products by hijacking John's forum. Pathetic.