@ Steve: Yes- I`m talking about woven hemp. Thermo-Hanf - der natürliche Dämmstoff für ökologisches Bauen
In germany we sometimes use it to isolate buildings. The density and the weight of "Thermo- Hanf" (so it`s called in germany) is similar to rockwool. I want to use hemp in my truck because I`m afraid of the fact that rockwool might possibly cause bad diseases. I used rockwool for more than 20 years for building studios and now I will try a new way. Especially for people with allergic diseases.
On the pictures you can see basstraps I built by using hemp.
Glass: perhaps I used the wrong english word: I was looking for an manufacturer of glass- or fiberglass- walls in order to prevent drumsounds from leaking into other mics on stage.
I didn`t know clearsonics yet- but that`s what I was looking for. I just found a german dealer for clearsonic. Thank you for your help!
@ Rolo 46: Yes of course the last (visible) layer will be fine old wood. I want to keep the mystery of the truck!