Barry Hufker
Well-known member
I'm very happy to have your reply to this topic. I was afraid my B.S. detector was failing me. But what about the testimonials? Are they legit, and if so, why?
Barry,I'm very happy to have your reply to this topic. I was afraid my B.S. detector was failing me. But what about the testimonials? Are they legit, and if so, why?
This x 1000!….
Acoustics and monitoring is infuriatingly complex and there is a lot of motivated reasoning and frankly cynical behavior going around. I've positioned and tuned thousands of sets of speakers and done some heavy lifting acoustically for a lot of names you'd know and I've decided that it's not a viable business. I've given up trying to hold back a tidal wave of bad ideas.
Cheers,
Ruairi
I seem to recall active room acoustic modification being done on large performance spaces back a couple decades ago. It seems like it would be easier to add reverb than subtract it.Just read this thread and it reminds me of a fascinating paper (copy attached) I have in my library about acoustic absorbers, but this one is electronic, circa 1953. Not being an acoustics expert (but I do understand the usefulness of traps), I find the microphone and the loudspeaker he constructed for the purpose the best part. Surely someone makes an updated version of this idea ...
As always, the place to start is basic room geometry.
I appreciate the info and don’t take it as salesy (maybe I’m naive?). I appreciate manufacturers explaining their reasoning. I find tube traps effective at some things, but grossly overpriced for my clientele.I work at ASC, and am happy to find answers to your questions about TubeTraps. One thing that should be pointed out is that they work best in pressure zones, which means corners, or up against other room boundary surfaces. We took some up to NWAA labs to have them tested in the corners of their big reverb chamber. Ron Sauro generously offered to do additional testing with the TubeTraps in the middle of the room to see if they worked just as well there. He thought they might. They didn't. I thought that was great. He's a very knowledgeable guy who was willing to test his understanding with a device unfamiliar to him. He made his prediction first and then put it to the test!
The tube shape is not what's most important for it to work the way it does. What it needs to be is a sealed chamber that air can get in and out of but only by going through a resistive surface, which is what the section of fiberglass tube provides when there's a cap is put on both ends to keep air from leaking in through the ends. These can be built as cubes too, and we make products like that. The tube shape has some advantages, one being that a high frequency reflective layer can be added to one side or both sides to act as a poly cylindrical diffuser, because otherwise the TubeTrap ends up being a broadband absorber, which isn't always what's needed. High frequency diffusion can be added to cube shapes as well, but it's not poly cylindrical, and it's not as adjustable.
Some physical criteria for determining absorption at different frequencies are the resistivity of the membrane, the surface area of the membrane, and the internal volume of the cylinder or cube. Also to be considered are any isothermal properties inside the tube that work to change the effective volume, similar to how a stuffed subwoofer cabinet will change the speaker's resonant frequency compared to the same cabinet without stuffing.
Here's a good article to read about how TubeTraps work.
https://www.acousticsciences.com/technical-papers/listening-room-corner-loaded-bass-trap-aes-1985/
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