D-MAN

Well, horns are horns, the only thing different is the wavelengths involved! Exactly the same physics apply. If you reduce excursion (by any means, including increasing the acoustic resistance), distortion goes down, bandwidth narrows, and efficiency goes up. DM

Mike is right about that, efficiency has everything to do with bandwidth. The problem with bandwidth is that the wider it is, the higher distortion; of course, that means that efficiency is lower, as PWK noted, efficiency and distortion are inversely related. Using drivers with a rising response curve (they get louder as they go up in frequency) is one way to increase the Fh. That doesn't solve the distortion problem, though. One benefit of dual-drivers is that the efficiency is doubled, allowing a higher bandwidth (and lower efficiency) to be used, and an added benefit is that the IM distortion is lowered due to less required excursion compared to a single driver. Using 2 drivers balances out alot of things. So comparitively, the use of dual drivers allows for lower operational efficiency (but still comparable with a single driver) and a wider bandwidth, and less distortion because of the drivers being operated well below a single driver's capabilities. Its a balancing act. DM

If the deer could shoot back, I assume you wouldn't like it then. Not that I have anything against hunting, but that's my point: Your accent on liking to KILL is quite a bit different than merely liking to HUNT. I grew up raising cows and when the time came to kill them, I didn't particularly like doing it. But that's killing. Not the same as hunting where you work at something and EARN it, and the animal at least has SOME CHANCE. So which is it, you like to HUNT or just like to KILL? I find your signoff a bit disturbing. DM

Those "Q" parts are called glue blocks. Standard woodworking stuff for assembly. They are far too small to cause any problems in the low frequency bandwidth of the bass horn. Use them as pictured, with plenty of glue and screws. They are permanent. Klipsch uses them too! DM

Yeah, the KING of unforgettable lines...it's a dead giveaway (pun intended). "now I know what your thinkin'. Did I fire 5 times or 6? To tell you the truth, in all the excitement, I kinda forgot myself. So you you gotta ask yourself: Do you feel lucky? Well, do ya - PUNK?" Here's another one (different movie): " I've always been lucky when it comes to killin' folks."

Nice amp! I want one of those. DM

Gil, the concept-level explanation on the multiple flare rates is that each flare section of a different rate is an acoustic transformer, and transfers the acoustic resistance to the mouth of the next section. Length of the respective section is only important in that it partially determines the acoustic resistance in combination with the particular flare rate, it is the nature of a horn to change a high velocity, small area to a low velocity, large® area along with the acoustical resistance (high to low). The acoustic resistance desired at the THROAT of the TERMINAL SECTION is the determiner. Multiple flare rates typically have a wider bandpass capability than a single consistant flare rate throughout the horn. This is also why the Khorn is 4 octaves vs. the usual 3 octaves, it uses 50, 32 and 40Hz flares, respectively. In the case of a fast expansion (throat section) the driver "sees" a lower acoustic resistance at the throat which allows for rather small throat cavity openings and throat channels to be employed. The rapid flare rate allows for a wider bandpass and higher efficiency (SPL) which includes the frequencies below the Fc of the section; the remaining horn sections of lower flare rates tend to filter the upper portion but present the least resistance to frequencies below that of the throat sections LF cutoff (Fc). So that "levels" out the response, and explains how you can get LF response out of a horn with a throat flare rate of 97Hz, as is the case with the Jubilee. The acoustic resistance at the throat of the intermediate section is lower due to its flare rate, and the fact that the secondary throat occurs at some distance from the initial throat, and there is the capacitance of air in the channel times distance from the driver/throat. The intermediate connecting section is a lower flare rate than the terminal section (required to "transmit" the acoustic resistance to the terminal section). If the intermediate section was a non-expanding column (or pipe) the acoustic impedance would be transfered 1:1 (ignoring any losses due to viscosity) to the end of the column. The terminal sections are typically the longest in the horn sequence comparitively, and the flare rate fo the teminal section determines the overall Fc of the horn. In the case of the LA SCALA, the throat section is the lowest Fc (60 Hz) and the terminal section is the highest (125Hz). This was done in order to use the large throat cross-section (78 sq. in.) for the use of the K33E. I'm not going to post the formulas for calculating all of this, frankly because I don't understand them - they use an "acoustic Ohm", for instance. They can be found in Harry Olson's "Acoustic Engineering". When figuring the use of multiple flares, the horn is worked backwards from the terminal throat back to the initial throat, so you start with the terminal throat resistance you want and work backwards, throat to throat. DM

Tell us what you think of the low end? The "weight" and "solidity"? Overall depth? etc. Impact, sense of dynamism? How do they compare? I have a couple of very specific things that I'm interested in, since my horn is folded like a Jubilee but has the splay angles of a Khorn. I'm looking for the differences you perceive in having 2x12" drivers vs. a single 15". I am familiar with the sound of a K33E. I agree that it has a certain sense of transparency that is pretty unique, etc. Dana

Mike, I would like to say that your opinions of the differences are very interesting, since you are familiar not only with the room and its "idiosyncracies", but especially because you have and are used to Khorns in the same room, in the same placement! This is as close to a A-B test of these two interesting designs that most of us will ever get, so your opinions are VERY IMPORTANT! Don't let my blabbering about technical crap stop you - Keep posting your opinions and impressions! Dana

I've often wondered about the actual effect of the front baffle. The central planar baffle on the front of all side-firing bifurcated corner horns is an important point - it prevents waveform curl-around at the horn terminal exits, near as I can figure. A handheld SPL meter should indicate the actual distances and overall pattern of the diffractional elements. I don't have one, but it would certainly be cool if somebody here mapped it all out for us! Dana

Mike, don't be taking this the wrong way, I've just been analyzing some of the differences between the Jubilee and the Khorn, that's all. It is true it was measured outdoors, however, a "true" 1/8 space is a pi/2 (or 1/8th of a sphere) radiation angle, it would occur in both indoor and outdoor spaces (doesn't matter) where the perpandicular intersecting walls and floor are high/long enough to form a boundary compared to mouthsize for practical purposes. The size of the 1/8th space radiation angle is determined by boundary limits (ceiling, wall length, etc.). The only thing that you won't get outdoors is the "room" gain or any benefit from modes or reflections, as well as the ability of an enclosed space to build up and store acoustic energy like a capacitance. Other differences of outdoor testing is caused by variances in humidity, temperature and an unrestricted (or infinite) volume of air that is likely to be somewhat unstable (windy) do to thermal considerations; there is much higher absorption. It's a true anechoic chamber, meaning simply that there are no echoes. However, what I am saying is that the Jubilee mouth is not a perfect match to the 1/8 space environment, that is a trade off of the splay angles employed COMPARED to the Khorn. A 1/8th space radiation angle (either indoors or outdoors) looks like this (attached) - I drew a rather bad drawing of what I'm trying to say. The cavity spaces on the sides of the terminal exits caused by the splay angles of the Jubilee mouth are subject to diffraction. No way around that one. That entails a loss of acoustic energy (small, but there). For an example, see the LB76 patent with wings to prevent that to a degree. Am I saying that the Jubilee needs that? No. Just making a comparison with the Khorn, that's all, which by its way of becoming part of the corner itself, is not subject to diffraction around the sides. The wavelengths being reinforced by planer reflections are another matter. That is frequency-specific, as long as the waveform is 0.75 wavelengths or closer to the reflective surface, and that means only the upper frequencies would be subject to fall off there (LF wavelenths are very long, of course). That would be for example, 19 inches for 500Hz, 12" for 800Hz, etc. So it can be seen that the falloff of reinforcing reflections would start around 900Hz for 11" distance from the side walls. I don't know what the actual distance is between the exit channel side and the nearest wall, that measurement would be critical in determining the best crossover point. Also, natural diffraction could be somewhat helpful in this case. Dana

What you are reporting makes sense to me. Two things are going on - the Jubilee has a bigger mouth area than the Khorn, sized between 1/4 and 1/8th space and therefore makes less demands on "clear" wall length than the Khorn, comparitively. The propagation characteristics are different due to the splay angles of the Jub mouth, too. As for going as low, the Khorn on technical merits should win out in an environment suitable for its best propagation, it has a longer horn pathway, which in horns, is a characteristic that is perhaps the most important thing for a smooth response after an appropriate mouth size. The Jubilee is not as likely to provide as smooth of a LF response as the Khorn is capable of (in the "right" environment) simply due to it having a shorter horn pathlength and a slightly larger overall throat size (comparitively speaking). However, like it has been mentioned, certain rooms are not optimum for the rather demanding Khorn. So it is indeed quite likely that the Jubilee is a better overall acoustic match to "most" listening spaces. The Jubilee is more subject to diffraction events than the Khorn in that there are cavity spaces around the mouth when placed in a corner. I beleive that this is why the Jubilee paper states that the LF response is diminished or lessened somewhat when placed in a corner. The trade off is that it can crossover higher, and due to the folding in a consistant plane, the available transient response should expectedly be more consistant, as phase information is "retained" to a larger degree. DM

the P is a 1970's version made by CTS. The "E" current version is made by Eminence. See (and save) the attachment in the second post of this thread here: http://forums.klipsch.com/forums/thread/772304.aspx

yup, smells like crap to me! Sonics for the K-mart crowd. DM

This is America, dammit, and Bigger is ALWAYS BETTER! But seriously, I prefer larger diameter wire, my internal wiring is 12 AWG. DM

I heard Khorns demoed on HT with gunfire so loud, I swear I needed hearing protection! I thought something would fry in them for sure. But they took it in stride. Anyrate, it was much louder than I would ever listen to them at... on purpose, anyway. I really have no idea how loud it would have to be to fry the woofers. I would expect the tweets to go first. DM

Yea, one I know! Deliverance! Strangely, one of my faves... Dang, she's good!

Here's another "definitely-not-a-chick-flick": ".. you got a real purdy mouth." If that one didn't curdle your milk, I don't know what will... DM

There you go!

Over 594,562 served. (not including this one)! DM

That is just too much! Although if the back chamber was painted white, the drivers might think that it was a smaller volume, so indeed black was the better choice there! :^)) DM

Gil, you painted the inside of the back chamber? DM

What, no takers?! Hard to believe from this macho crowd! ("-or were they? Hmmmm, I wonder...")[but that's another film, though] here's a clue: it's a Peckinpah film. Give up? DM

Rick, Way to go dude! (on more than one account, too - I got the tractix horns you sent). Dana

Tony, that's probably a safe bet. The LB patent states a 78 sq. in. throat, and we know that the Khorn, LS and Belle all have that as the throat size, BUT still use a smaller slot, the 3x13. I think if you used a different driver than the K33E, the larger full-size cavity opening would then be in order. I'm looking forward to seeing more about your project! Dana