What do you think of this Bass trap design?

[Jens Eklund]

Velocity based vs. pressure based absorbers

[OpusOfTrolls]

One trouble of this design is secure mounting. You can't just have screws on one side of the mass. Doing it the way you propose will result in a loose coupling which won't transfer as much force to the panel, as well as possibly vibrate against the wall at high SPL. There needs to be screws on both the inside and outside of the trap's furring. While it might seem unnecessary, consider imperfections of both the wall and the furring, where the amount of pressure on the surface is unequal along the length. Where it is loose the trap might vibrate against the wall, and gravity will lever around the screws which also causes less coupling on the inner side of the furring.

[seeren]

Thanks for the link, and the installation shortcoming. I've been wracking my brain to come up with a solution to mount these in the corner. I'd love to be able to screw in from behind, but how? The only thing I can think of is to build the frame, install it, put in the insulation, cover a panel with fabric and attach that to the frame.



Any better ideas?

From the linked thread & the links within that thread, it seems like I should consider doing away with the solid panel front, maybe using perforated panels or maybe just an open frame, and make the rear panel solid. Then tune for specific freq's along the walls. Did I get that right?

[Jens Eklund]

4m x 5m x 2.5m room - modal resonance problem

[Glenn Kuras]

I don't think it is going to work how you think it will. For one something 100% tuned needs to be flat on the wall and 100% sealed. Also wood, IMO is no the best membrane to use for pressure traps (tuned traps). I have done a lot of testing and can say that if you do not understand pressure based trapping 100% then I would stick with velocity based (broad band). You can use FRK or thin card stock on the front of normal rigid fiberglass that will reflect upper frequencies and act as a membrane to absorb more low end.

[OpusOfTrolls]

Your revised design is better. But Glenn is correct and if you really want a solid panel trap, do some research and read a few books. The design as it is now will work well as a perforated panel.

[seeren]

Thanks, guys. Since this is my first experience with treatment of any kind I don't have any frame of reference as to its potential, other than people saying it is one of the most important things you can do.

With Jens' links, and sublinks conveniently referenced in this thread, I have a good amount of leads to read through this weekend.
What Glenn said is pretty much what I was afraid someone was going to say, which is good, and exactly why I posted.

Edit: Good to know, Opus.

[DemonWithAHalo]

I have a question. If one were to switch the wood to a membrane, as Glenn said. Would putting another piece of 1" foam behind the main 3" piece with an air gap between the pieces of foam as well as between the small piece and the corner of the walls increase the LF absorption?

All of the literature that I have read on the subject has mentioned this, but I have never seen or heard of anyone doing this. Then again, I do not know much about the design of many of the products out there.

[DemonWithAHalo]

foudn the answer to that in another post.... this forum is huge.