WMcD

In earlier months there were complaints that people wanted to go to showrooms to hear Klipsch speakers, but there were limited numbers on display. Probably true. Now people are saying they can get good prices by mail order. Probably also true. The retailer who has the overhead for a demo room is in a bind. A potential buyer comes in, listens, and buys elsewhere, from some mail order outfit without the overhead. You can see where this is heading. Gil

It could be done, but with great effort and error. Basically you'd have to buy a few Heresy's and take you the mid and tweeter and crossover. Then select a smaller woofer and build and design a small box for the woofer with an eye for the typical 80 Hz cross over freq of HT systems. I don't see any cost effective way of doing this otherwise. It would take a lot of scrounghing around to re-create the components of a Heresy and then the effort of building a proper crossover. I'd say to you should just find a way of living with the bulk of the Heresy's. Gil

The "scientific" end of me says that no one should reach a conclusion before making an A-B comparison. On the other hand, based on general laws of physics, putting a big piece of rock under the woofer is not going to do anything. Save your money for more CD's. Gil

Gee, I dunno. It is my understanding that the K-77 has always been a handpicked, rebranded T-35 from EV. Therefore, you should be able to get a new diaphragm. I had to lighten up your pictures. It appears this is a bass refex box. The woofer has a wizzer cone. The only other speaker is the tweeter. Is that an oil filled cap? I noticed that Cabinart in 1955 sold several variations on the Rebel horn. What you have doesn't seem to be that. However, there is also mention of a Rebel-Ortho which in context does not seem to have a bass horn and might have been a reflex. It is supposed to be a 3 way though, and yours is not. Perhaps yours is a home built unit. Are there any labels, brands, serial numbers, or the like, hidden on the box itself? Gil

Since even the mention of titles bring on vague reminisences of unspeakable horror, perhaps we should only call them "Nameless Dread #n." Gil

Yeah, I had to look it up to be sure. My reference says that copper has a resistivity of 1.724 microhms-cm. Silver has a resitivity of 1.628 microhms-cm. Thus Silver is a better conductor. This brings to mind that copper was in short supply during WW-II. Hence the steel pennies. The Manhattan Project borrowed 395 million troy ounces of silver from the U.S. Treasury for use as windings in cyclotrons. That is 13,540 tons. Interesting fact for the night. Gil

Sorry to not be able to give you any info from here. It will be the first of the year before I can get back to the project. I did some work on cutting plywood inserts to decrease the back chamber volume. I want to force up the resonance and get some more reactance annuling. I'd like to be able to show some experimental results showing frequency response versus resonance. That will take a lot of experimentation and measuring. Gil

"Mandy" gets my vote. Part of this is because it was inflicted on suffering listeners so often. By that standard, "Its a Small World" must get an honorable mention. That song, from the 1964 NY World's Fair, was even mentioned in Lion King. Guitarzan needs some discussion, too. Gil

I can see no technical reason why this will make any difference. Silver, I believe, has a slightly lower resistance than copper, given the wire gauge. However, please recall that the very dominant resistance in this loop is the winding of the tweeter. It is about 5 ohms. And the winding on the T-35 is copper. Gil

While we're on the topic, can someone tell me the size (depth) of the spacer on the factory unit? I've heard some describe it as an extra gasket. TIA, Gil

John, Thanks for the inquiry. Unfortunately, Ive bitten off more than I can chew, again, considering time and talent limitations. Ive been working on the three units for my high school. A lot of time has been taken up working on veneer and finish before installing the hardware. So, acoustic testing is just ramping up. In the interest of science, and the journey, and advice to other builders, Ill give you a long post, as follows: Mechanically, the installation of the bass driver and motor board was made complicated by my decision to close off much of the back chamber. You see this in the early photos. It was difficult to get the washers and nuts on the far side mounting carriage bolts. No room for a wrench or hand. That was solved with wing nuts. I should have seen this coming but did not. (Self delivered head slap.) None the less, see below that reduced back chamber volume is an issue. I got to play with the LMS and the almost complete units over the weekend for about a half-hour. Real solid measurements and tweeks will take days. But a few things are evident. The midrange horns (Fc = 400 Hz) are working very well. The midrange horns are so classic that they cant go wrong. But the driver is a source of problems. The quick test was with an EV-1824 driver. I tried that driver on my similar plywood variation of a K-400 years ago and the results were poor. Eventually I rigged up a plane wave tube and found the 1824 driver ragged in 1 kHz to 2 kHz range and rolled off sharply at 3 kHz. Naturally, the overall horn response suffered. This recent test on the mini horn showed about the same. The 1828 tested much better on the plane wave tube years ago. Also, anechoic measurements of the big midrange horn with the 1828 were very favorable. So, I think the smaller midrange horns will be okay with a better driver. Even with the 1824, they have good response down to 500 Hz. So Id say the geometry is correct. Yes, Im waiting for the new Atlas driver to come out. The mini pseudo LaScalas bass units need adjustments. Even with the reduced volume of the back chamber, the driver system is resonating at 85 Hz and Id like to see it at 100 Hz. The response from 200 to 500 Hz is about level and even goes to 1 kHz, at 102 to 104 dB at 1 watt/ 1 meter. Therefore, I believe the choice of the Eminence Beta 10-A was a good one. The problem is that there is a big dip in the 100 to 200 Hz region (I was not hoping for anything under 100 Hz). One consideration is that this measurement was near a floor-wall intersection and not a corner. However, I believe the response will be better if the back chamber volume can be reduced to get system resonance up to 100 Hz. I tried doing that by putting some scrap wood and spray paint cans in the back chamber, all that came to hand. However, response fell overall and I believe I failed to get a good seal at the hatch. This is consistent with an air leak. Then I ran out of time. Rats. Id like to do some serious testing on the effect of back chamber volume and bass response. A hazy explanation is that reactance annulling requires the system resonance to be at the frequency where there is the big hit of mass reactance from the finite horn around cut off frequency. An old paper by the Jensen people implies this. Ive found that pushing system resonance up to that frequency is non linear with back chamber volume. I.e., Ive reduced back chamber volume but it doesnt force up the resonance as much as is expected because it is getting into an area of more mass reaction, requiring even more spring in the back chamber. Horn design continues to be a good hobby. Im reminded of Journey to the Center of the Earth. Arnie Sarknuson (sp???) left a description of his journey and some trail blazing marks. Yet explorers have to find their own way. It is an interesting trip. Regards to all, Ill keep you posted. Gil

The box, direct radiators in the Heresy don't lend themselves to any big improvements by hot rodding. Overall, I'd not recommend gross modifications to the unit. A subwoofer is a better approach and is part of the HT movement. Gil

Thanks for the encouragement. Sometimes it is needed to keep up enthusiasm. Three units already have a walnut veneer applied to some surfaces. I'm planning on mahogany for the other two units. Okay, okay, I'll do a good job on the throat. Elmer's wood putty with some careful filing has been doing okay for me. I started the project thinking they would turn out with the quality of a fine violin. But that was unrealistic. At least they may reproduce like a fine violin. Gil

Thanks Al., The file names shown have no spaces, even though the uploads do. After some fooling around I got the upload to work. I have some Eminence Beta 10 A for the bass and 1824 and 1829 for the mid. One will get my remaining T-35. Selenium has an adapter to put a screw on driver on a 1.3 throat. It is to go up against the round plywood throat. I have to trim and fill with putty. I'm of the mind that 10% error with rough putty at the throat is not going to make too much difference. Perhaps over-optimistic. However, they work well enough on the other three beasts. The real test will be with the LMS. I understand from your posts you got a measuring system. In my experience, the bad news is that it can show up a lot of irregularities. On the other hand, it is good to have the real story and work on solutions. Gil

I'd promised updates. The theory is that a 66% near copy of a LaScala could be used for a center and surround. Naturally, there will be reduced bass response. A problem was building a midrange. I built a 400 Fc midrange. The top and bottom surfaces are flat but angled. Then the sides are filled with strips of wood and trimmed. The bass unit is 16 x 16 x 16 and I've used a strip in front and a smaller chamber. I a few weeks I will mount drivers and give you some test results.

Thanks, dks. I'll have to figure some repeatable testing conditions and give a full report. Giving some more thought to the initial question. I agree with John W. IF the unit is only used for deep bass, and IF efficency is not a consideration, and IF you really want to work with the Khorn, can we alter anything. The hallmark of the standard design is to get efficency and bandwidth (somewhat in conflict). But we are not too interested in those here. One thought is that the output is not going to amount to much below the resonant frequency of the driver and chamber combination. That is pretty much set by the size of the chamber. It is determining most of the compliance. On the other hand, stuffing should increase the effective size of the chamber. Also, there are many drivers with very low resonant frequencies. You might be able to knock down the resonant frequency. IF I had to experiment, I'd look for a driver with a high Qts up to 0.7 and a low resonance, down around 20 Hz or less. I'd stuff the back chamber with a full load of material. An 8 ohm driver is okay. My guess is that you're going to wind up with an output somewhat lower in low frequency cut off, with reduced efficency, and unknown smoothness of response. Consider that you are looking for two octaves out of it from 25 to 100 Hz. I pick those numbers because they are one octave on either side of cut off. That is terra incognito in horn design. I think it is a grand kludge. But if you are absolutely determined, that is one way. I've thought about getting another octave of bass below the KHorn. It is not too tough to design and build a band pass sub woofer with a one octave response from 20 to 40 Hz and decent efficency. I'd use that to supplement the bass. That is the way I might go. Gil

SunnySal, It is not entirely a stupid student question. And somewhat profound. In truth, much or all of this is about impedance. We are working with impedance because it is an inherent propery of the systems. Perhaps that should have been the first answer. We're working with systems which are not simple. Gil

Okay, so the inference was correct. I use six machine screws into T-nuts to hold on the hatch. It is stiffened because I have a piece of ply there to attach a side wall. I was looking through some old Audio magazines while making copies of the article on the Patrician for buddies on the board. The ads show various kits for the EV line of corner horns. They are described as K-Horns. My impression is that EV cut the boards in all cases. I'd think that PWK got his royalty without having to cut and ship wood. Gil

From some cut aways I've seen, and some comments on the bbs, I get the impression that parts of the bass unit from Hope are made out of 1/2 inch ply. Maybe I'm wrong. Gil

Hmm, very interesting on the updated 1570. I bought mine several months ago. My recall is red flecks. You've invited the question: What did they change . . . and if you know, why? Gil

So, John W., does this mean you have a Khorn made from 3/4 inch ply? You make me feel good. I had built the SK using 3/4 inch which took some figuring and extra work. Later I noticed that the Hope product used quite a bit of 1/2 inch, and thought my additional efforts were over kill. Perhaps not! I also have backs on them. This might improve things over a poor corner. Incidentally, I think Klipsch fanatics have no gripe with Patricians and Imperials. They're close cousins. Gil

If you want a suggestion on an alternate driver for a K-Horn and SK, I'm using a Pyramid 1570 from Parts Express. It works for me. I can not claim it is "better" than a K-33 or K-33-E. However, if you're a tinkerer, you might give it a try. Regards, Gil

Sorry guys, I might have been stepping close to the impolite line. I get too wrapped up in it all. I'll send anyone wanting it the article on construction of the Patrician. Putting this together with the Speakerlab plans, a builder would have a good start. The design of the Patrician midrange seems to require a driver which is rear loaded. It looks like Parts Express is selling such a device now. It could be done! Gil

My experience is the same as indicated above. If one tries to maximixe utilization of the boards, and also taking into consideration of the size of the driver, there is a pretty tight sqeeze to make things work. Overall, I think it is not so much of a problem with performance overall. Gil

Hmmm, why does anyone assume there is an improvement to be accomplished. The K-Horn works very well. It is a bit annoying that there is some assumumtion that the the design is not optimised. Gil