Horatio

Yes, the DDS horn has polars and they look pretty decent. It's a 70X60 coverage unit, 150-2K responswe horn (they recommend to use it 250-1.6K). The main thing that moved me to look hard again at that unit, is the RCF 10" driver: This is sealed back, and can be had with a phase plug. In a 90X 40 horn, this thing does 109 db for sensitivity (!). I would think it is possible, with a good DSP, to tart up the upper end of the PWK bass unit to correct for the swinginess in the response, but it does not do anything for the phase response, nor the polar matching with the mid horn. The way to deal with this is to use a straight shot for the upper midbass/lower mid, with decent polar management, and then time align it with the DSP. Keep the bass as bass, and carefully work the upper end. At least that's the logic i'm following. Short of finding a good pair of Emilar EC600's and decent matching horns, I don't know of a better way to attack this area. Packaging gets to be a real issue.

It's been a while since I've frequented this forum, but, I have an idea I wanted to run by folks here: I have used an EV HR9040A and HR90 in search of improved lower mid performance on my system (speakerlab bottoms with K33E's/crite's critters in the bottom). Love the HR9040, but it's enormous. Still doesn't quite fix the low mid end. I have been looking at an RCF MR10N301, a 10" sealed back very high efficiency midrange, with a phase plug, going into a DDS DMB-10N horn. This looks like a combination that ought to work for 250-1.5K or so. This should make a serious run at that low midrange upper mid-bass area I've been after. I will have to figure out a good combo for the top with that, but the HR90 should do this without much trouble (whole thing is getting big again...). Thoughts? Anyone use one of those DDS horns for this type of thing? The RCF unit is quite sensitive, and coupled to the horn should provide more than enough sensitivity with respect to the bass unit. Thanks! Mike

A direct feed of SPDIF to the PWM inputs is close to digital nirvana. I'll have to look into that-thanks! Checked out the Crown amps- pretty slick product. I think these speakers are woefully overpowered by an amp of that size, though, don't you? I had that worry with the MF100 100 watt amps I'm using; can't imagine what something larger'd do on these speakers. Thanks for the heads-up on this stuff- Mike

What I'm using: I'm kind of old school, in that I am using a Hafler preamp, which has two line outputs, one of which is driving BK (U.K.) Electronics MF100 Mosfet amps (these are mono modules, and I have six of them for triamp purposes, but only use a pair in this configuration, for the bass section) feeding the inputs of Type A crossovers, of which only the bass and the tweeter sections are active. The other output is driving a Rane AC23 crossover, of which I am using only the midrange, with CD equalization for the HR9040/HR90 horns. The upper cutoff is set to feather into the Type A's cross to the tweeters. The midrange output of the Rane is fed to a Sonic Impact Tripath amp (the obnoxiously cheap one that is still rediculously nice sounding), which is what, maybe 8 watts? This is a hackneyed setup to be sure, but it sounds pretty dogone nice, believe it or not. My intent is to crib something up that gets into the right neighborhood (proof of concept, really), and then, make a final pass with the right set of DSP gear to tie it down well. I know alot of guys don't like Behringer's 2496 series, but, it seems if one's careful to stablize the clocks and then to pay attention to the outputs to the amps, it oughta be reasonable to stay digital all the way to the point where the amps appear, and do with with reasonable quality. CD -> SRC -> DQX -> DCX -> amps. I have been considering doing a complete PC-based setup, looking for a stable sound card (uh, yeah) that I can set up for use on my system (e.g., using the 5.1 or whatever outputs as independently programmed channels, so that I can set eq, delays, etc., etc. Flexibility is the driver- the basic hardware and compute horsepower's there- what's needed is better software). Not all that easy to do, still, with decent quality, it seems. Much further ahead to use outboard commercial DSP-based stuff, at least at this point. Have not looked into the Crown model you're speaking of. Will do.

Yes, I've considered making the measurements...I've done a quick glance at the links in your last message and see you've been on the track, too. I'm kind of moving broadly in the direction of complete system equalization with respect to the in room response. Far from getting there, at this point, but, this is where I think I'm headed. Agree on the false corners part: in my case, the corners aren't exactly perfect: I have a house with alot of windows, even though it was built in the 1920's, and the front windows are floor to near ceiling, multipane swing out types. The horns sit in corners that do not allow good sealing, as the sides are against the window borders, etc. The room I'm playing them in is pretty large, relatively speaking. I suspect that sealing these up a bit better would improve matters. Lots of compromise here, to be sure, and it undoubtedly influences the sound I get. I did not know that the later models of the Khorn used networks to EQ the response a bit more- I lost track after Type AA.... I figured to simply boost and attenuate my way to smoother response viz, HR90 integration. Right now, I do it by ear, listening to lots of different source material. Yes, it's a bit of an exercise in relativism, but, there's a certain self consistency that eventually results. I think I'll see if I can get hold of a decent parametric EQ unit and see what develops. Appreciate the comment on the problems of opening up driver bandwidth- one of the surest ways to screw up the sound, especially if you're dealing with marginal drivers to begin with, is, push them outside their intended range. The converse is also true; you can take some pretty cheap drivers, and, provided you narrow the range of use, can make them sound pretty decent. I figure if quality pro sound compression drivers can handle, say, 40 watts continuous at 400 hz, and the response curves go lower, they oughta be pretty good on a couple of watts peak, a bit lower. Yep, the distortion goes up, but right now, what I am hearing in the lower midrange in terms of amplitude response is washing any increase in distortion, at least right now. Qualitative statement, to be sure! Actually, the distortion question is a good one on another point: the EV CD horns, the early ones, used a hypex expansion in the throat, and so, one might expect more distortion as a result. The interesting qualitative consequence of this design is that the wide, stable radiation pattern and smooth frequency response seems to trump any distortion concern right away; compared to a straight shot exponential, these are really really nice to listen to. Thanks, Mike

I am not eager to cut the 9040's down, either. Not surprised that they are getting rare: they are enormous! But, I also have to say, they sound really really nice. They do look gangly on top of the corner horns, though, spilling off the sides of the bass unit by about 3" each side, and bringing the whole stack to a height of just a few inches shy of 6'. I bought them originally to do the top end on a pair of University Classic bass horns I built. They are stunning together, and the size fits perfectly, even if the pairing is visually formidable. What I would like to do, is, simply EQ the bass horn a bit in the 300-400 Hz region, to boosting it to catch up with the HR90, which CAN be integrated easily into the cabinetry. What I don't know, is, how well does the bass horn respond to EQ'ing this range? Anyone done it? I agree that a possible change in driver could help a bit, but, you know, I have listened to these horns with the original WS1504's that Speakerlab put in them, and I've also put a pair of EV15L's in them, and I must say, the K33E's sound WAY better than either of those. So, I am inclined to stay with the K33E's and try to EQ these into correspondence with the HR90s. -Mike

I have not posted on this forum for some time, but, I have reached a point in my messing about that I am writing to ask for input. The story so far: I have a pair of Speakerlab K's, factory built. However, these are running K33E woofers, and are using Type-A crossovers. Those two steps alone vastly improved the K's, to the extent that they are, for all practical purposes, indistinguishable, from a sound perspective, from the Klipschorn. This much is well established and shown by others, too. Most of us are aware of the changes PWK made to the midrange over the years, questing to get it right. Most of us are also aware that our KHorns have a (pick your adjective, here) woody, muddy, closed sound in the lower midrange. This seems to me to be the most common criticism of this speaker, from a sound perspective. One of the objectives leading to the 'Jube was the need to extend the upper end of the bass horn's response, of course. And, many of us amuse ourselves with different changes to the midrange horn: tractrix horn, Altec 311/511/811?, etc. I fall into this category as well. I have spent some time messing around with the original CD horn family that EV (Keele's design) invented in the mid-70's, and I have a pair of the HR-9040A's (the great white whales) and a pair of the HR90's, the little brothers to the great whites. Of course, these need to be equalized, and I run a biamp setup with the horns equalized per EV's specs. I am using a well respected English Mosfet amp on the bass side, and feeding this directly to the Type A crossover, so it is rolling off per stock Khorn design. The midranges are being fed from a Tripath amp (rediculously good sounding little amps, these things), and they are crossed in using the usual L-R 24 db/octave network. The midrange drivers are EV DH1012H's. The tweeters: I am using the Eminence APT's on the top; I like them better than the EV T-35's I have, although they are a bit hot, and need to be padded down some. It may just be that the T-35's are a bit tired and could use new diaphrams. Right now (you won't believe this), these are coming off that Type-A, along with the bass horn. Now here's the thing: putting the HR90's in play makes a substantial improvement in the midrange overall quality. The sound stage is wide open and very very stable. You'd expect that, after all, this design pretty well solved (and started the run toward CD designs in all their permutations) the beaming problems with straight shot exponential horns, and offers a very stable set of polar radiation patterns. The HR90's are rated to be used to 800 Hz, and EV states that they can be used to 500 Hz. I use them at 500 Hz. The drivers can go lower, but the horns won't load them much below 500 Hz. The sound is very very nice to my ear. Still have that wooden lower midrange, though, and you'd expect so, since this is the relative notch in the response between the bass section and the midrange (whether the standard exponential horn, or the HR90). This notch is probably worse with this setup, although it is hard to tell, when you A-B the HR90 against the stock 400 Hz exponential. The smooth, wide open sound the HR90 makes it very hard to go back to the stock 400 Hz horn in these systems. The HR90 can be built into a reasonable form factor with respect to the top unit of these speakers: it's not all that much taller than a stock Klipsch setup, considering that the HR90's are pretty good sized horns. Putting the HR9040A's in play makes yet another improvement: these are rated for use to 400 Hz, and can be used as low as 350 Hz. The DH1012A, while rated to 400 Hz, is conservative: it'll take the full rated power at 400 Hz, but the driver responds nicely well below 400 Hz. Since I have NO plans to feed THAT much power to it in my living room (!), it is reasonable to drop its crossover frequency down to 350 Hz. Used in this way, the woody, muddy character of the sound simply goes away. It is full, powerful and clear. I cannot hear defects in the response through this range, at least whatever defects there may be, they pale in comparison to the standard setup. This arrangement is simply stunning to my ear. FWIW, I use the 1st Nora Jone's release to judge, because her voice is pretty husky in many songs, and the piano and bass give a good test through this range, too. It's very easy to hear the difference changing the midrange horns/drivers makes. The HR9040A's are nearly 40" wide and about 17-18" high. To get them to fit reasonably to the bass section would mean that I would need to trim the mounting flanges back a bit (well, more than just a bit), just to get them to fit, width-wise. The HR9040A also can be made to fit within a top cabinet that mimics the standard system (e.g., flat front; as big as this horn is, it's not all that deep, really.), although you're now talking about a speaker that's going to end up about as tall as a Jensen Imperial or so. All this can be done, to be sure; but, you know, when I A-B right and left sides, one with the HR9040A and the other with the HR90, it's hard to find fault with the HR90, as long as you are not talking about the lower midrange. It's clear that the HR9040 wins, but, the HR90 just isn't all THAT much of a compromise. And, it's head and shoulders better than the stock midrange, again, to my ears, anyway. So, my question to you all: is it possible to profitably equalize the bass horn's response to boost that lower midrange region? This'd be another good way to address the issue: I can easily fit the HR90 to this setup and it's not going to be a big deal. Pretty much the same dimensions, etc., etc. So, if a decent parametric EQ can bring this notch up to snuff, I'd contemplate using the HR90. It may also be possible to parametrically EQ the 60-100 Hz range, too, so that this response is a bit better (like the 'Jubes) here...I know, some of you will say, 'why don't you just get a set of 'jubes?', and you have a point. Thing is, the standard issue PWKs are pretty damned good...they just need a little rouge here and there to tart up the response, you know? Again, can the bass horn be profitably equalized in the manner I've described, or is this not the way to go? Clearly, I have a solution with the HR9040A's, it's just going to run the ragged edge of domestic peace. Thoughts?

I will be trying out an EV HR90 w/ EV DH1012 soon, and will report back to this forum on the results. If it is anywhere as clean and open as the EV HR9040's I'm running on top of University Classic bottoms, it ought to be an improvement over the mid/top of my khorn clones (speakerlab builds with K33E's and Type A's). The HR series requires active equalization, as they are (the original) Constant Directivity design.

Suggest that you also look at the crossover aspects- I have found when biamping and triamping horns, the crossover slopes are steep, and this works fine on the low-end cutoff for a driver (say, midrange or tweeter), but, what you want in the bass section, is to really allow that woofer to contribute to higher frequencies. This is one of the reasons why the Klipsch Type A works so well- it is a gentle slope, but combines with the steep roll-offs of the midrange and tweeter (at the low end of these drivers) well, while allowing the woofer to go higher, relatively speaking. Most active crossovers that set the low/mid cutoff, will roll the woofer off at the same frequency and rate as it rolls the midrange in. If your woofer's response is on the decline in this region (which is most definitely is), you really want to use a different slope, or a higher frequency for the woofer, as opposed to that being used to cross in the mid. Of course, you could equalize in this region, also, and use the crossover directly set. Try this: drive one side on your crossover, and feed the same channel to the other side (e.g., drive both channels of the crossover input with the Left channel, for example). Then, take the low frequency output of the second channel, and drive your woofer with this. That way, you can independently set your woofer crossover frequency. I think you will find the performance of your bass horn will improve as you raise the crossover frequency beyond your original setting (which is where your mid range is coming in). Another way to try this is to simply put the 2.5 Mh inductor on the woofer (I can't recall- is your woofer 8 ohms or 4? The 4 ohm woofer uses the 2.5 Mh in the Type-A, I think), on a full range signal sent to your bass amp (e.g., T off the input to the active crossover and drive your bass amp this way, and use the inductor as a passive crossover for the bass horn), and use the active crossover to handle the mid/tweeter. Finally: I have a set of Speakerlab-built Khorns, and I never got these to sound right until I loaded them with K33E's and put a Type-A crossover in. I tried EV15's, along the way, too, but nothing sounded as good as the K33E in there. Have fun!

Jeez, Duke, those are monsters! How many elephants had to be killed for your system? On this proposed biamp situation: FWIW, I am going to try Sonic Impact Type-T amps for the top end on my system. Got a couple on order (what? didn't PWK say something about this country needing a good 5 watt amp? At $30 per, no less? Read the web reviews A-B'ing these guys against triodes? Too much of a tease to resist at $30 per). I am using BK Electronics monoblocks (U.K.) for the bottom (100W/side); never been happy with anything other than a solid MOSFET bottom end (I'm an old Hafler 500 guy at heart).

Been looking at that DCX unit, too. An email into Behringer got a response on setting this up for the CD equalization needed for an HR9040. Amazingly, they build analog eq's with CD compensation capability built in. But, they did not set up the DCX with a CD compensation library. You have to mix and match the core eq functions available on the unit. But, the DCX can do the time alignment without incident, which is more difficult to do with an analog eq that has delay (I have a Rane AC23, and the delays have to be moved around to get them where you want them, on this setup). Master volume: some pick up the digital conversion model (e.g., does up/down sampling of digital sources, etc. etc.) of the 2496 series (I can't recall the model, scx or some such). This takes SPDIF, does AES out (which the DCX likes as input, and avoids an A/D step), AND it has a master volume knob. For about $130. Jeez, once you do this, put their DEQ-2496 in between...yeah, you can go crazy... but, it's an all digital chain from the CD to the backside of the DCX, going into the amps. Also, there's an excellent French site on mods for the DCX, including extensive how-to on setting up for unbalanced use. Put www.dcx2496.fr INTO the yahoo search engine (don't enter it into the browser directly, unless you can read French). This way, you'll get Yahoo's ability to on the fly translate into English, and you can make headway. I have been chasing down a similar path, as you can see. I have already tried the HR9040 with a University Classic bottom, in a two way, and it's pretty nice. The HR9040 is quite big for the Khorn, but it's kid brother, the HR90, should integrate very nicely, if you make a slightly taller top hat for it. I'd go for the HR9040, if you can negotiate domestic peace on the visual on the results. Otherwise, try the HR90. Good luck!

<I had been looking for the smaller EV 120 horn> That's a good sounding horn; if you get the chance, though, I'd go with the HR90 (little brother to the HR9040 you're considering). It's got better pattern control. BUT, unlike the SM120, which if I recall, is an exponential radial, the HR90 is a CD setup and MUST be equalized. My opinion is that these give the best shot at a credible two way. When Keele designed these, he noted a certain resemblence of these (HR9040, at that time) to the Klipsch patent horn which, at one time, was the upper end of the Khorn before it went three way. FWIW.

Hey Bodcaw boy: Thanks for your inscrutable response! I will look forward to the next Klipsch Co. developments. And yes, you can have the thread back (as if I took it in the first place...[]). I see that my work here is done []. This HAS been a great deal of fun to read, and I have a much better appreciation for the extraordinary level of interest, competence and knowledge of the folks posting here. It's really a rare thing to find this much interest focused on horns, especially today. Outside this list (and maybe the Asylum), it's a bit like wandering in the wilderness. Thanks guys! H.

I'm not so much replying to this specific post as to the thread. When I originally made the first post opening this thread, my question/challenge was to think outside the box, in terms of how we approach horn-loaded systems. In particular, I offered up, along the way, two concepts (sub, Khorn/Jub style, with 'satellites' that were two way, and another concept: cylindrical wavefront/omni system). We have seen subsequent discussions debate the relative merits of Khorns/Jubs/Scoops/etc., and alot of discussion on folding. It sort of reminds me of reading the literature of the 1950's again, but with a modern twist. We have found pretty much all the basic ways to fold a horn, and to fit one into a corner. We have some pretty good designs for this. We are treading familiar ground, again and again. To go back to the original question: what's next on the horizon? I submit that we have tapped out the potential in our present methodology, and our improvements are incremental. One thing that has come out in this thread is the very present need for measurements. We have designers on this forum who design and design, and we think we are improving, but we rarely have measurements to support this (although we DO have the very important golden ear'd impressions). Somewhere along the thread I picked up a comment about PWK, and his affinity for 'rough curves'. This is a great comment, because it sheds light on our problem: first, we need to measure. Second, we must decide WHAT to measure, and third, we need to figure out what to do when something measures well, but sound's bad, or measures poorly ('rough curves') but sound's great. If it measures good but sound's bad, we're measuring the wrong thing. An example: I saw someone post about a Huygens reflector design style in their folding geometry. That's a conceptually interesting thing- what is its impact? One of the cool things about the Jub style of folding is that (in addition to being a walk in the park to build, compared to a Khorn), it ought to lend itself to direct measurement of the acoustic wavefront (I don't know quite how this'd be done, but, you have direct access to the path in this design, and our measurement technology today is substantially more capable). It would be really interesting to make measurements of just what DOES happen to the wavefront as it propagates through. And the question of whether Huygenian reflectors help or not could be directly answered, among other things. Lacking direct measurement, surely we have indirect measurements that could make such comparisons (e.g., the standards, frequency response, IM distortion, and so on) of the effect of subtle changes to the folding geometry. Indirect measurements ultimately, though, will not inarguably answer the question of what it happening to the wavefront. But, all this discussion of corner foldings and relative merits...it is rather like the fellow who lost his wallet in the alley, but is hunting for it by the street light, because it's brighter there. We can continue to debate the merits of various foldings and driver combinations and so on, but the original question still stands lurking in the darkness of the alleyway: what will the 'next big thing' be (unfettered by our predisposition to work with what we have and know...)? When I looked at this a lonnnnggg time ago, it was apparent to me that the polar radiation patterns were much more important than we had thought. I ask again: if we are reproducing music that is recorded by a transducer with specific properties, including a very defined polar response, ought we not be also attempting to design transducers that play back with these same kinds of properties? <playing the cantankerous crank, here>

I don't know about the size of the Jub- the biggest problem with the HR9040 is the mouth size is very large- if the Jub is at least 40 inches wide, then, it'll go. Watch how tall the whole assembly gets, though; it'll be imposing. For reasons of domestic peace, I have the University Classics/HR9040's in the rec rooom, and the Khorns in the livingroom. My setup is a few inches taller than a Khorn, and about as wide. Since the Jub crosses out much higher than the Khorn, you might want to look at the HR9040's little brother: HR90. Same horn, but good to 500 Hz, pattern controllled to about 800 Hz. This guy is well within the size constraints of a Khorn top (maybe a little taller, but not much). Either can be used as two-way; they go up quite a ways with good drivers. May want some supertweeter on top, but, then again... Thing to note: the HR series, like all CD horns, MUST be equalized in order to sound good (that is, the drivers' power response must be eq'D flat). I biamp, and the electronic crossover I use has the CD EQ built in (RANE AC23). Most prosound crossovers will have this on board.

Escalate?!?? I don't want to debate this point into the ground, but I suspect my earlier point earlier about dual 12's was misunderstood: of course, a SINGLE 12 will, as you say, NATURALLY have MORE EXCURSION to accomplish the same task as a SINGLE 15. My point is that TWO were used in place of a SINGLE 15. Thus, for similar output, the TWO 12's will have less excursion, collectively, than the SINGLE 15. I am interested in your comments on the drivers for the Khorn: I've used Speakerlab W1508S, W1504S (long, long time ago), Eminence (can't recall now, something like 151311?), EV15L and K33E's in LaScala-like (own custom design), University Classic and Khorn designs (not all drivers used in all designs). In particular, I found that the Khorn only came alive for the K33E. I'd be REALLY interested in which 15" drivers you were thinking of in that last post. I am also interested in your speaker design, as you say it crosses higher- that'd be a useful contribution (you probably posted it before, and I just haven't looked). I had been planning to EQ this region.

Here's the data. They're big: about 40" wide. That's about as wide as the long dimension of the University Classic, so, they work great on top of it. With a driver attached, they fit, depth-wise, within the depth of the University Classic design, also (not INSIDE the mouth of the Classic, but on top). Check out the stability of the polar response! That has audible consequences. Can use EV DH-1012 drivers, which can be had for a decent price, and are pretty credible drivers (I use these instead of the 1506's to go down further in response). HR9040A EDS.pdf

Hello: These aren't mine (I have a set, running on top of a pair of University Classic bass horns, biamped, equalized. The sound is spectacular), but, for those willing to take a walk on the wild side, behold: http://cgi.ebay.com/EV-Electro-Voice-HR9040A-2-sound-PA-horns-empty-pair_W0QQitemZ160044927252QQihZ006QQcategoryZ47092QQssPageNameZWDVWQQrdZ1QQcmdZViewItem Lots cheaper than trying to find Altec 300-90's, and these will astound. Need 1.4" drivers. FWIW.

Less distortion: yep, that's also a byproduct of using 2 12's: the cone area goes as the square of the diameter (factoring the pi/4 out of the picture), so, looking at a 15": 15^2 = 225, whereas 12^2 = 144, but, there are two, so: 144+144=288. So, 2 12's give (288-225)/225 * 100% = 28% more cone area over a single 15. So, two 12's give not only the upper bass extension that the Khorn was lacking, but can do it with less cone motion (for a given SPL), and so, with less distortion. The issue concerning their use in Jubilee is not so much their contribution to lower overall distortion, or to obain lower bass; one could use a single 18" driver to do this, distortion-wise (inasmuch it will have 12-13% more cone area than 2 12's), and could drop the low end response if the horn could be made larger. The issue is getting the extension in response at the high end, so that better handling of the midrange could be accomplished. THAT is why they're being used in that design.

D-Man, I enjoy reading your stuff! I agree that the goals need to be clearly defined, when we talk about new designs, or even mods. And we are in a very subjective arena, much like the tasting of wines. Both areas can be made amenable through the application of science, but in the end, it is the emtional experience we're after. On the use of dual 12's: dual 15's wouldn't be better; the reason, I would submit, that the 12's were used is that their mass roll off is always going to be further up the range than a set of 15's. This is part of how the upper bass region was dealt with. I have been reading the stuff that Dr. Who has written with great interest, too. This is bringing me back to consider the speaker system as the inverse or compliment of the microphone setup. There's a lot tied up in this statement, as it goes to how many mics and how they're set up and mixed, for starters. In the 1980's there was a great deal of discussion in audio circles about Deutsche Grammaphone's then-prevalent technique of multi-mic'ing, vs. the relatively minimalist approach of Telarc's. The sound of the recordings was astonishingly different, with the Telarc recordings almost always more pleasing from a sonic illusion perspective (performance considerations aside, now). The point of this is, all of it matters: the microphones used (frequency and polar response), their quantity and location, how they're mixed, and what the recording engineer is listening to when sweetening this. The end result is going to sound different on every system EXCEPT the recording engineer's. Even on the recording engineer's system, the sound is going to be different than that experienced in the hall by an observer. Unless great care was used in mic choice and location, and the objective was to re-create the observer's experience. Since most mics are omnidirectional, shouldn't our speakers be so? I know that the fans of Magnepans and the electrostatics (any dipole radiator), and the Ohm Walsh series (omni) like their setups because of this sonic illusion. The trade I make is on the superior sensitivity, transient response capability and utter dynamic range of horns; in MY mind, THESE parameters are more meaningful: they are more powerfully emotive for me. And yet, when I hear a set of Magnepans, I think...hmmmm: if I could get that with my horn setup, that'd be nirvana. So, this leads me to another suggestion on alternate designs: the omnidirectional horn. Also not new: If I recall correctly, Hilliard did an omni (well, cylindrical wavefront) horn system for a World's Fair in the 1930's. I'm thinking something altogether different than Hilliard's though (that one was comprised of many exponential horns arranged in a cylindrical coverage pattern). Suppose we make ring radiator: maybe an electrostatic element, or something like a Heil element (anyone recall the 1980's SpeakerBuilder article on a DIY Heil?). And we couple this to a horn that is axisymmetric: an omnidirectional (well, almost) system. Then, we use a folded, downward firing woofer to get the bass (to take advantage of the acoustic resistance offered in this arrangement). Hmmm... wonder how that would sound?

That's an interesting point- I am unfamiliar with pro recording techniques, and I would suppose that the recording made from the direct-outs would sound different on a horn system instead of a direct radiator. It would probably sound ALOT different. I am not a musician, but certainly one can find several makes and models of woofers, all directed at guitar amp applications, extolled for the various sound attributes each has. One is led to believe that the driver is in control of the specific kind of 'great sound' one gets. This must inevitably impact recording practice. Is it the low frequency extension or the lack of distortion, or, is it a specific type of distortion that the Khorns exhibit in the mid-bass? I don't know...it's just that the comments about 'thwack', punchiness, or, my personal favorite: 'woody vocals' persist about the Khorn's sound in this part of the range. On the matter of tweaking the distortions: this is why I am suggesting that our approach must neccessarily include signal processors in the loop, to equalize drivers for specific horn geometries, to smooth response, etc., etc....is this always going to be considered a bad thing, or will it just persist among purists? Another way of seeing this: we play around and play around and PLAY AROUND with passive crossovers....are we not doing the same thing (fiddling the acoustic signature)?

Boom3 got it! The earlier comment on the EV Patrician was right in line with my opening statement: the EV Patrician could also be viewed as a Khorn mod'ed out with three exponential horns to do the midbass on up. I think a really fun set up would be a Khorn (bass only) sitting away in the corner (just about everyone has at least ONE corner that would work, especially if the corner didn't impact the listening arrangement- seems to me that this is the common situation, and not the exceptional one required to run classic Klipshorn cornerhorn systems), and two, call them satellites, but they'd be bigger than the usual satellites, units that use perhaps equalized drivers to do the rest. Probably can get away with two-ways, here. I have been away from this thread since first posting it, and have appreciated the commentary. Thanks! On the mid-bass problem: anyone here have experience with the Emilar driver that was set up for mid-bass? I have a musician friend who also does pro sound, and he waxes raphsodic about the old Emilar what was it, EC600? You know the story: owned a set, sold them, and later regretted it.

Excellent point. I have not heard a Jubilee, but have just read the AES paper, and of course, read in this forum about listening experiences. This is the nub of it, though: the mods we make to our Khorns, La Scalas, Belles, are made in a direction that that Jubilee went, esp. with respect to the midrange. We try to address the issues latent in the original design, however good the original design was. Please understand, I am not saying the Jubilee is not worth hearing, not at all. My point was more that, our mods to the classic designs have become somewhat circular. We need to break out of that. Jubilee shows significant, step-wise refinement of a classical concept- that is what the title of the AES article intends to state, I would submit. These designs will almost always be considered competent reproducers. I am trying to poke at us to prod us to think beyond this. I myself have built copies of these excellent, old designs. They work very very well. Perhaps I'm pushing to solve that ancient Greek geometry problem of squaring the circle...

I agree that the technology in the sub market has evolved considerably. I am somewhat dubious of this, as those systems to which I have been exposed seem pretty heavy-handed and not real listenable. Maybe I need to find a credible system and give it a critical listen. Yes, the midrange issues are rife with mods like the 311/511/811, and the trachorn. I don't know about the sound of the Altec horns, but it's got to be an improvement, if for no other reason than the mouth size lends itself to fewer reflections. Since they are expontial horns, they undoubtedly still suffer from the polar response issue. The trachorn, and the Voight tractrix family in general can potentially do a better job, but, we have design technology that ought to enable us to render horn shapes that are part waveguide that, with equalized drivers, should give great frequency response AND excellent, stable patterns (and concomittent imaging). These approaches come up over and over because they either a) rely on the use of existing, better designed exponential horns, or they rely on keeping a horn that permits 'drop in' insertion to an existing system (that is, they might require minor crossover tweaks, but not much else). Very few are willing to brave the use of, say, a CD horn, which will require active equalization in order to achieve its objective, but which would yield an entirely new level of performance. My point is, we keep trying to appeal to those classical approaches, and we keep ending up in more or less the same place. We need to think differently if we are going to arrive at another, better, place. The automotive situation offers good insight: I have a friend who works for Bose, and we often get into discussions about the active equalization that is done for automotive audio systems. These systems know, for example, if the convertible top has been lowered, and change the system response accordingly. They self-calibrate. This kind of technology will be extremely helpful to rendering a new solution to an old problem. I will admit alot of ignorance on this area, as, I am still rather old school in my home setup: Hafler pre-amp and a bank of B&K (English) monoblock MOSFET amps. There is, I'm sure, already technology of this general type making its presence known in the consumer market. The pro sound guys have some fantastic tools available. The apartment case is a real problem; these spaces are always going to be a struggle for full horn systems, in the sense of wide range systems. Although, along these lines, the 'Fostex-style' two-ways (German design running around on the web) can do a really really nice job, in a compact package (again, my son and I built a pair of these and they work stunningly well in his very compact dorm room). I have also seen another design that is very unusual, but workable for this case: imagine two, four foot square sheets separated by about 6 inches, with the full range driver in the middle of one of the sheets, and the driver back-loaded with a horn that radiates from the periphery of the 6" thick edges. The 6" space is divided into four tracks that exponentially expand from the center, one track to each side. THAT is a design that could be mounted on a wall, or hung from the ceiling, or...many possibilities for small spaces... Still, a more conventional design, with say, a mid-bass driver with a short front horn in a vented box, and a tractrix-style or CD or waveguide top with a good quality compression driver, paying attention to the polar response behavior during design, ought to be doable in a box of reasonable size when one curtails the low end to around 150 Hz. Paired with a conventional sub, this could be pretty good...

Hello all: I have recently joined this forum, and have made only a few posts. In terms of background, I have designed a la scala- based horn, and cut my teeth on the issues of trying to improve an existing design, working with the Leach/Plach/Keele sources on throat and back volume, etc., etc. I have built a pair of the so-called Fostex-based two-ways (with my son, while he was in high school; they now pretty much rule his college dorm, nothing can come close, or so he says), I have built a set of University Classics (with a somewhat unconventional approach to the top end- EV CD horns), and I have wrestled with the ownership of Speakerlab K's, finally transforming them to an acoustic copy of the original Klipsch design. I have been reading with great interest, the many posts here on Klipschorn/Belle/La Scala mods, and of the projects along the lines of classic designs. In particular, I have read about the Jubilee system, including the AES paper describing their design. While mods can be made to the original Klipschorn, and many of these can be really efficacious (I'm thinking here of the various approaches to handling the midrange, primarily, although there's lots to do with crossovers and tweeters, too. Very few change anything on the bottom...unless they're working with a Speakerlab K, in which case, they change to a K33E and slap in a Type A crossover...), I wonder if we're off track a bit (maybe I just am not on the same page as to where this collective forum is going...). I like mod'ing as well as the next guy, but I think we are making end game refinements to a design concept whose constraints we can't avoid. I do not dispute the greatness or significance of the design; it is remarkable that a 60 year old design can put most of today's general loudspeaker product to shame. Physics is not often bought off by the next pretty face. For example, there are countless ruminations and designs for alternate bass horns...it is really really hard to get lower than the Khorn, in any similarly sized package...build after build shows this. Even the Jubilee trades absolute low end for somewhat smoother passband and extended upper bass, relative to the Khorn. Where I am going, is this (and it is not terribly original- those who've been to the volvotreter web site know this): What if we focus on a so-called satellite-sub design, based on a Khorn, crossed out at, say 150Hz. Then, we work on a two-way satellite that is horn-loaded. Here, I am thinking of the front lenses that DDS makes, on a healthy 10 or 12 inch driver really optimized for upper bass, for the bottom of the satellite, and a really open sounding horn on top, where we take care not only with the frequency response, but we are paying close attention to the directivity. We also have less time delay issues to work with. Finally, isn't it about time that we begin thinking about the design of such systems in conjunction with the electronics (not only in the ususal sense of loading, and so on) in the sense of active equalization? Can we not use CD horns, or horns that, in order to give the desired pattern control, must be in some way equalized? Such an equalization scheme could also potentially deal with the response of the Khorn bottom in the 50-150 Hz range, too, to smoothen this out somewhat. Such a system would go a long way toward addressing some of the age-old issues we've been talking about with respect to the Khorn (bass response, mid-bass and lower mid-range behavior, patterning of the midrange and tweeter, and lastly, the fact that the Khorn just can't deliver that 'slap in the face' response that say, a VOT can do (again, the mid-bass, lower midrange problem). Thoughts? (thought I'd throw a piece of raw meat in the house!)