hsbrock

@Rudy81 I have been studying your posts for some time now, and have a few questions, if you might help me? Assuming AMTs in a dipole Tractrix Bi-horn front & rear... and for dipole OB I should have 1m between the VC and the rear wall, and I so have been considering moving the mouth of the rear horn as close as 8" from rear wall, and adding distance/delay to the soundwaves with an slow-expansion exponential labyrinth between the rear of the AMT and the throat of the rear horn, with the mouth of the rear horn about 8" from the rear wall, but I wonder, How well might 400-10kHz soundwaves travel through an exponential labyrinth - if the soundwaves won't bend, will they reflect or bounce adequately and cleanly enough (presuming the walls are hardened) if I have curved corners or 45-degree blocks? The goal is to enable placing the drivers closer into the corners without having them out so far into the room. With this much distance, would I run into phase issues and breakup? Can I keep an adequately clean sound feeding into throat of the rear horn? Surely the same principles apply as with sub horns. With aluminum being the third most reflective surface to bounce sound waves (behind silver & gold), I was considering lining the interior of the labyrinth with a sheet of heavy weight aluminum foil before it feeds into the rear horn. There would also be diffusers within the mouth of the rear horn to spread the sound horizontally and vertically to expand the stage & prevent direct bounce-back. So my concerns deal with the sound progressing through the labyrinth because I cannot find anything about how higher frequencies propagate through a labyrinth. I've assumed an slow exponential expansion to avoid standing waves or back-waves, i.e., the throat at the rear of the AMT expands very gradually to the mouth of the labyrinth/throat of the rear Tractrix. I sure am hoping someone might have some insights!

It has taken me some time to read this thread, and I have been intrigued. Are Rudy81 or Chris still available to answer some questions? Do you men mind if I run something past you? I'm a newby to this site, recently retired. I have wondered about the problem of not being able to provide adequate spacing between the rear AMT drivers used dipole and the rear walls, and if the problem could be solved by inserting a labyrinth between the rear of the AMT and the rear walls. I understand why it is ideal to have about a meter spacing, but, like you, who has all that space to position their drivers out into the room? So, in wondering about this, I have asked myself about adding about 60" (5') in distance by having the rear of the AMT feed into a slow-growth exponential labyrinth of only 3 turns, and the end of the labyrinth being the throat of a Tractrix 7-9" horn (that would effectively duplicate the front horn radiating directly into the room). I understand that higher frequencies do not like turns, but why? And at what frequencies do they cease behaving similar to lower frequencies? My understanding is that they don't, and from what I read, they bend/diffract around corners the same, based on their frequency, and if the labyrinth were 1 1/2" wide by (increasing from 8" to 16" high)...why not? From my calculations, it seems to me that the frequencies should bend around a 1 1/2" corner up to about 9kHz, or would it? And what doesn't bend could be bounced/reflected with 45-degree corner blocks, providing solid waves into the throat of the rear horn. (Then the mouth of the rear horn would have lens/vanes/diffractors to spread the waveguide as best.) The inside of the labyrinth could be covered with either large, hard, smooth, glazed ceramic tile, which is harder, heavier & stronger than glass. On the other hand, the three most reflective / least absorbent materials, better than steel or glass, are silver, gold, and aluminum. So maybe the inside of the labyrinth could be covered with heavy gauge aluminum foil, spread smooth and attached with a fine-spray adhesive during construction. My corner-horns are about 30" wide, so to insert a labyrinth in there would be: 15" to the right + corner + 30" to the left + corner + 15" to the right, to arrive at the throat of the rear horn. This would add 60" to the length, plus 6-8" behind and back, would total about 85-90", or better than 2 meters, or about 6 ms to the time delay, which I understand is the time needed for ideal spatial positioning, thereby extending the spaciousness of the room, and with the diffusers inside the rear horn, it seems it could achieve the same effects as having the speakers a meter away from rear-side walls. It seems to me that the distance should be long enough there shouldn't be phasing issues. In order for the sound to not to lose its energy or be dissipated, it is both very reflective and has adequately heavy mass throughout the labyrinth. Sound diffracts at the same angle it hits the barrier, so if it hits at 45 degrees it will bounce off at 45 degrees, and make it around corners, shouldn't it? Or, does it? This thread has posed to me a few questions like this one, but this is my first. I'm hoping to find some answers. I've had plans done on this and then I encountered this thread. Can either of you expand on anyone that has attached horns to an AMT? Do you know of anyone that has attached an exponential labyrinth to AMTs? (Must be expansion to avoid standing waves.) If soundwaves are not absorbed, they should travel the distance without dissipation just like in free-air, shouldn't they? One question I wonder about is, what could happen with IM distortion? What am I not thinking of? I lack the experience to answer these questions, and am hoping someone might have some answers or ideas. Thank you, gentlemen, for considering my questions.