Edgar

I stand corrected on the K-402. Greg

Not raining on my parade, you're saying the same thing that I did. My mistake was apparently in choosing the 402 as an example -- I am not familiar with its radiation pattern, so I assumed that it was narrow horizontal and wide vertical. If the 402 does, in fact, have tighter vertical control than horizontal control, then in "landscape" orientation it's already in the best configuration to minimize floor and ceiling bounce. Each horn is unique in how it controls dispersion. Most of the non-multicell pro-audio horns that I have encountered have the narrower beamwidth associated with the longer dimension. But there are always exceptions. (On edit: Looking at the current EV catalog, I see that it's pretty common for short, wide "landscape" horns to show larger horizontal dispersion than vertical. However, they cannot maintain their vertical dispersion to nearly as low a frequency as their horizontal dispersion, presumably because of the smaller physical dimension.) It still might be worth experimenting with "portrait" orientation, because in the near field the pattern can be significantly different than in the far field. Greg

It's counterintuitive, but at any given frequency many horns have a narrower radiation pattern in the long dimension than in the short dimension. Using the 402 in traditional "landscape" orientation as an example, this means that the pattern might be only 40° in the horizontal direction (the larger horn dimension) but 90° in the vertical direction (the smaller horn dimension). For sound reinforcement this can be a good thing; it means that the entire audience from the front row all the way to the back row is covered, but the side-to-side radiation is controlled and kept from being bounced off the side walls of the auditorium. In the home, however, it might actually be better to use such a horn in "portrait" orientation. This way the sound is kept from being bounced off the floor and ceiling, but it still fills the entire room side-to-side. Certainly worth trying. Greg

You're welcome. Also some interesting Interface D woofer info here: http://www.audiokarma.org/forums/archive/index.php/t-110854.html Greg

Here's the scoop from my friend at EV: Hi Greg, I checked with our service department and they list the Interface D as not repairable. The VMR (Vented Mid-Range) appears to still be repairable assuming he doesn't have a large quantity. If he wants to send the in here is the contact information: Bosch Communications Systems 1 Telex Drive Morrilton, AR 72110 Phone 800-685-2606 If he does send them in he will need to fill out a form. It can be obtained from the following link, which also has the addresses for service: http://www.electrovoice.com/contact.php?t=5.5&c1=1&c2=74&c3=&p=&z=55311 Another option, especially for the Interface D speakers is to contact Bill Hanuschak at Great Plains Audio and see if he can help: GREAT PLAINS AUDIO 7127 NORTHWEST THIRD ST. OKLAHOMA CITY, OKLAHOMA 73127 (405) 789-0221

I haven't been with EV since 2000, so I don't have any insider info. But I'll check with some of my old colleagues there and see what I can find out. Greg

Yes, installation drawing is what I mean. Sometimes, just banging-away at the keyboard, the subtle differences don't really occur to me. Greg

I agree. In that respect it is similar to the HR9040A, which has a conic section connected to an exponential section. The 9040A is a CD horn. That strikes me as really odd. When I worked at EV, we provided all of that info, in great detail, for system installers. Greg

Messages coming in faster than I can keep up with them ... Perfect. Thank you. Greg

Thanks, a "ballpark" figure will be good enough for the time being. I really appreciate your help. Greg

Thanks. It would be so much easier if there were just some engineering drawings available. Greg

I'm trying to design an enclosure into which a K-402 horn will fit. I'm actually designing for multiple HF horns, the EV HR9040A being the one with dimensions most similar to the K-402. Designing for the 9040 is easy, as I have a couple examples packed away in my basement. But I don't have a K-402. Greg

Yes, that would be fine, thank you. I didn't realize that the driver had a screen, but that provides a convenient reference for where the horn stops and the driver starts. You are most accommodating. Greg

Interesting. Klipsch brochure says 40.3" x 26.0". Always a good idea to measure! Got it. Yes, it does. Yes. The brochure showed a throat region that looked to be about 2" long. Perhaps that was a prototype or something. Yes. You'll probably have to hold a straight edge across the mouth and measure internally to the throat, perpendicular to the mouth, being careful not to accidentally jab the diaphragm in the process. I'll understand if you don't want to risk it. Sincere thanks, Greg

Still in the "I wonder if they'll fit" stage right now. Thanks. I need the three measurements indicated in the attached rough sketch; the overall length, the approximate "length" of the throat, and the width of the mounting flanges. The rest I can get from the Klipsch brochure. Greg

Where can I find a dimensioned drawing of the K-402 horn? I've looked on the Klipsch site and only found .pdf brochures with tiny, fuzzy drawings. I need enough detail to design an enclosure. Thanks, Greg

I remember many, many years ago visiting Pacific Stereo in St. Louis, and finding them trying to find a suitable amplifier to mate with the new Infinity Quantum Line Source speakers they had just received. The QLS defeated a Heath SuperAmp (something like 565 Watts per channel into 4 Ohms) and a Harman Kardon Citation (forget the model number, but it was a BIG amp); both amps STRAINED with these speakers. Then they connected an SAE 2200 (only 100 Watts per channel). Magic. Jim Bongiorno went on to Great American Sound, then Sumo. I think he's freelancing in California now, or is he associated with a manufacturer? Greg

You need to snug those horns deep into the corners of the pickup bed.

At work just the other day we were discussing the fact that our measured data didn't agree very well with our simulated data. Somebody recommended taking more measurements. I recommended developing better simulations. Greg

Pythagorean. That's how I came up with the expression for path length along the wall. If the differential length dL is the hypoteneuse, with differential distances dx and dr being the legs of the right triangle, dL=sqrt(dx²+dr²); then using Bruce Edgar's expression for dr/dx=-r/sqrt(a²-r²) you get dL=(a/r)dr, and so on. The bubble is not spherical, but rather is oblong with the longer axis in the direction of the horn axis. I have often used a spherical wave approximation for analysis, because while it's not perfect it's a much better approximation than a plane wave. The sphere has constant radius "a" and is trucated such that it contacts the horn wall perpendicular to the tangent of the wall itself. Tractrix is not perfect, though. Bruce Edgar told me that nobody uses Tractrix for bass horns because they don't provide a good load near cutoff. See http://forums.klipsch.com/forums/thread/994068.aspx for my proposed solution to that problem. Thanks, Greg

Roy, I know that I am responding to quite an old post, but I've only just read it for the first time today when the thread was updated with a new response. Please understand that I'm an engineer, but my specialty is signal processing not acoustics, so my understanding of acoustic waveguide theory is not as complete as I'd like. That said, don't acoustic waves propagate according to Huygen's Principle? If so, then the curvature of the wave front can intuitively be explained by differences in path length. If the portion of the sound wave adjacent to the wall propagates along the wall, while the portion of the sound wave in the "center" of the horn propagates straight down the center of the horn, and both propagate at the speed of sound, then the wave front has to curve. Maybe the easiest way to visualize this is to think of a point source in a flat baffle as a degenerate horn with instantaneous 90° flare. The wavefront will be hemispherical, not planar. BTW; the path length "L" (along the wall) of a circular Tractrix horn is easily computed from the Tractrix defining equation as: L=a*ln(r2/r1), where a is the mouth radius and r1, r2 are radii between which you want to know the path length (this corresponds to the nomenclature used by Bruce Edgar in his 1981 Speaker Builder article). So the path length (along the wall) of an entire Tractrix horn is L=a*ln(a/r1), where r1in this case is the throat radius. From the defining equation for the Tractrix it can easily be shown that the path length is much longer than the horn itself, meaning that the portion of the sound wave that propagated down the "center" of the horn exits the mouth long before the portion that hugged the wall even reaches the mouth. Hence, the "bubble" model of horn propagation. Greg

The only CAD program with which I have any experience is TurboCAD. It handles 2D and 3D, it does everything I need for speaker design (and a lot of other things), and it's inexpensive at about US$150. Older versions are readily available on ebay for far less than that. (I'm currently using v7.1; I just checked ebay and the oldest that I found was v9.1 for under US$20, including shipping!) And it can import and export DXF files. Greg

No kidding about Brrrrmont. I'm measuring about 18" in the Williston-Bolton snow corridor this morning; fallen since Friday. Supposed to drop to -10°F tonight.

Just in case anyone's interested, here's an example of the "Elongated Tractrix" contour that I mentioned earlier. In this case I have set its length equal to that of an exponential horn with the same cutoff frequency. As you can see, the Elongated Tractrix acts like a hyperbolic horn over the majority of its length (good low frequency loading), and then expands like a Tractrix near the mouth. I have not done ANY analysis of this contour other than to modify the Tractrix equation to be able to generate it. Greg

My experience with trying to design a 25 Hz horn has been ... disappointing. I have concluded that one would be better off using the volume that such a horn would require as the rear enclosure in an infinite baffle, along with a multitude of 18" woofers and lots and lots of Watts. (Dang it; how do I insert a clickable URL?) http://ibsubwoofers.proboards51.com/index.cgi Greg