I remember reading that from the corner outward, it only needs the first 4-feet of the wall. This is how PWK built his false corners for his home and wrote about in the "Dope from Hope."

I have heard that, effectively, Klipschorn bass units are 8-foot horns, so that would make the internal path about 4 feet.

 Does anyone know the exact number? If so, what is it and where can I find evidence of this?

Thanks

 Claude

From "A Low Frequency Horn of Small Dimensions", Journal of  the Acoustical Society of America, vol. 13, pp. 137-144(1941 Oct.):

"…With a frequency response down to 40 Hz, corresponding to a wavelength of 340 inches, comparable to the performance of the typical theater woofer, this unit measures only 39 inches high, about the same width across the 'wings,' and only 28 inches deep from the front panel back to the corner…

According to my measurements of a Speakerlab K (which I understand to be a pretty good copy of the KHorn), it's about 147 cm (58 in) internal. See here.

Greg

Edgar:

According to my measurements of a Speakerlab K (which I understand to be a pretty good copy of the KHorn), it's about 147 cm (58 in) internal. See here.

Greg

Thanks Edgar. It was helpful in offsetting my Khorn clones to time aligng them with the midbass and treble sections.

Claude,

I didn't understand your need.  Note that from Heyser's November 1986 Audio magazine article on the Khorn:

"The tweeter sound arrives at 3.7 ms but has an internal reverberation whose period is about 167 microseconds with a decay rate of about 9 dB per second.  This causes irregularities in the free-field sound around 6 kHz...The midrange sound first appears at 5.38 ms and shows a mild reverberation characteristic which pulls the energy out for a half millisecond or so before it drops.  Subsequent enclosure reflections occur after about 6 ms.  The first sound from the woofer is not on this measurement since it arrives about 8.4 ms after the sound from the tweeter."

Claude, as you can see, that 8.4 ms offset is a big delay relative to the Jub's 2.2 ms relative delay (ref. KPT-KHJ-LF bass bin and K-402/K69 upper horn assembly).

ClaudeJ1:

Thanks Edgar. It was helpful in offsetting my Khorn clones to time aligng them with the midbass and treble sections.

You're welcome. Be aware that the 58 inches includes the distance between the "foldback" nearest the corner and the center of the bass section opening on the sides of the KHorn. That is to say, it is approximately 58 inches from the throat through the 90° turn along the front face, through the 90° turn back through the "twist", through the 157½° foldback at the corner, to the opening of the bass section.

Greg

ClaudeJ1:

I remember reading that from the corner outward, it only needs the first 4-feet of the wall. This is how PWK built his false corners for his home and wrote about in the "Dope from Hope."

Islander:

ClaudeJ1:

I remember reading that from the corner outward, it only needs the first 4-feet of the wall. This is how PWK built his false corners for his home and wrote about in the "Dope from Hope."

With PWK being such a practical fellow (a La Scala is built from 1-1/2 4' x 8' sheets of plywood with little waste, for example), he could have chosen 4 feet for the false corners because he could use half a sheet of plywood for each side and it would be sufficient, rather than for purely audio reasons.

Yes, I'm sure that may have been the case. He did mention in the "Dope from Hope" that false corners beyond about 4 feet didn't contribute anything acoustially. I'm sure that 3 1/3 feet would be fine.

I did see those actual false corners at his house (the ones in Dope From Hope), so he definitely practiced what he preached!

Cask05:

Claude,

I didn't understand your need.  Note that from Heyser's November 1986 Audio magazine article on the Khorn:

 

Claude, as you can see, that 8.4 ms offset is a big delay relative to the Jub's 2.2 ms relative delay (ref. KPT-KHJ-LF bass bin and K-402/K69 upper horn assembly).

 

The voice coils on my tweeters and upper/lower midrange are all alighed. turns out I put the apex of the false corners of the Khorn bins IN FRONT of the lower mid which is about 4 feet forward from the natural corners where all the backs of the upper horns are jammed. It really sounds good and I'm sure it's less than a 1 ms. error at my 200 Hz. Xover point from the Khorn bin (it really is a WOOFER). Back to Khorns and no more MWMs for me. Much better bass in my room.

 at .89 milliseconds per foot, I can see where Heyser would measure that kind of delay, but to the midrange, it's probably in the 5 millisecond range. My treble horns are 4 feet further back than a K400/K55 driver in a Klipshorn top hat, hence the greater coherence of sound I get 9not to mention the lower Xover points and lower distortion from the large format driver/horns I use with the Khorn bass).

ClaudeJ1:

Back to Khorns and no more MWMs for me

Marvel:

ClaudeJ1:

Back to Khorns and no more MWMs for me

You got rid of your MWMs? That is hard to believe, Claude.

Not really. They are best suited for disco speakers because of the large hump at 50-60 Hz. before they plummet at 48 hz. or so with room gain. Basically the MWMs is a 6-foot horn, while the Khorn is an 8-foot horn, so they go lower. Yes I PEQ'd the hump flat, but the Khorn bass is deeper and more defined, without a doubt. Extensive listening of all kinds of test material and measurments bears this out.

After talking to Gary Gillum, who has built hundreds of MWMs and whose name is on the patent right next to PWK..........he told me the MWM was designed for the K-33 woofer and that the K-43 was made by Eminence strictly to handle more power, not perform better.

So if the K-33 is the best woofer for hi-fi, and I have a choice to put it in an 8-foot horn vs. a 6-foot horn, the choice is clear. Remember that I only used either one blow 200 Hz. where the curves and the 1/2 mouth spacing behave best. Above 200 Hz to about 1Khz, a straight axix CD horn with a phase plug and an 12" driver does a way better job than either a Khorn, MWM, Jubillee, or LaScala........I have had them all over the last 32 years.

What the MWM taught me is that I could "time align" them to the rest of the drivers and maintain a single capacitor in the network for the rest of the horns (natural mass rolloff negates the inductor) while using discrete amplificatin/Xover/gain control on the bass horns, since they are the least efficient (104 vs. 109-111  db/W for the rest).

So in my evolution in the last 2 years with the MWMs, I discovered that 4 was unnecessary (way overkill indoors) and busted down to 2 with a little extra gain....very good. I just improved it again by going back to a Khorn clone bottom with Crites woofers (old K-33's for all practical puposes). The false corners are 4 feet FORWARD of the natural corners where all of the other 3 voice coils are jammed into. This is BY FAR the best sounding setup I have ever had, with careful matching of all components has taken me over 2 years to evolve while maintaining ALL of PWK's principles of good sound.

There's a reason why the Khorn has laster over 60 years. PWK really got it right and it's very difficult and expensive to improve on this excellent design that has withstood the ultimate test...................time.

ClaudeJ1:

Not really. They are best suited for disco speakers because of the large hump at 50-60 Hz. before they plummet at 48 hz. or so with room gain. Basically the MWMs is a 6-foot horn, while the Khorn is an 8-foot horn, so they go lower. Yes I PEQ'd the hump flat, but the Khorn bass is deeper and more defined, without a doubt. Extensive listening of all kinds of test material and measurments bears this out.

I really don't see were you get the 8ft horn length for the Khorn. It is of an "approximate" finite length of 58" and then the mouths must be corner loaded(ie:natural or false) to take advantage of 1/8 space loading gain which serves to extend the systems response in a room. Of course even 1/8th space loading(ie:tri-corner) isn't a totally valid way to look at things in an actual enclosed space/room were other room boundries come into play. 

ClaudeJ1:

So if the K-33 is the best woofer for hi-fi, and I have a choice to put it in an 8-foot horn vs. a 6-foot horn, the choice is clear. Remember that I only used either one blow 200 Hz. where the curves and the 1/2 mouth spacing behave best. Above 200 Hz to about 1Khz, a straight axix CD horn with a phase plug and an 12" driver does a way better job than either a Khorn, MWM, Jubillee, or LaScala........I have had them all over the last 32 years.

Hey Claude unless you bought some Jubilees I believe you shouldn't include the Jubilee in your statement of having had them all? Unless you have actually used a Jubilee/K402 (for example) in your own room your conclusion is undetermend at best.

Also keep in mind that even though a straight horn with a single mouth could out perform a design like the Khorn or Jubilee (which is a bifurcated and folded horn design which was to acheive specific design goals) in a certain frequency range under certain limited conditions you must still mate it with other horns and integrate it with the room which then has it's own compromises so ultimate performance in context of the total loudspeaker system and room integration changes everything as it has since PWK first designed the Khorn.

ClaudeJ1:

So in my evolution in the last 2 years with the MWMs, I discovered that 4 was unnecessary (way overkill indoors) and busted down to 2 with a little extra gain....very good. I just improved it again by going back to a Khorn clone bottom with Crites woofers (old K-33's for all practical puposes). The false corners are 4 feet FORWARD of the natural corners where all of the other 3 voice coils are jammed into. This is BY FAR the best sounding setup I have ever had, with careful matching of all components has taken me over 2 years to evolve while maintaining ALL of PWK's principles of good sound.

Claude your conclusions about why you prefer what you do(between Khorn and MWM) are in question in my way of thinking because you really aren't comparing apples to apples IMHO for several reasons but one "very important one in particular". Your room's acoustics are unique like everyones and depending on were the mouths of the horns are physically located in this room will determine what your end results will be at any particular listening location in that room. Even if the two horns acoustical responses were identical once you changed were the mouths of the horns are located in the room what you perceive/like will be determined by this fact.

ClaudeJ1:

This is BY FAR the best sounding setup I have ever had, with careful matching of all components has taken me over 2 years to evolve while maintaining ALL of PWK's principles of good sound.

All designs are a balance in compromises! I would differ with you on following all of PWK's principles of good sound and call your attention to the fact that PWK always expressed and designed for as few horns/crossover points as possible to acheive each systems design goals. To overlook this is to overlook the history and orginal design goals of the Klipschorn. The fact that his personel decision and design goal for the improvement of the Klipschorn was a return to a 2-way Horn system is a clear indication of his principles for sound and what direction improvement would come in and it wasn't to complicate and make it a 4-way design and then try to make all 4 Horns acoustically sum again.

Anyway I'm really glad you enjoy your system Claude because that is very important goal in this hobby!

mike tn

ClaudeJ1:

The voice coils on my tweeters and upper/lower midrange are all alighed. turns out I put the apex of the false corners of the Khorn bins IN FRONT of the lower mid which is about 4 feet forward from the natural corners where all the backs of the upper horns are jammed. It really sounds good and I'm sure it's less than a 1 ms. error at my 200 Hz. Xover point from the Khorn bin (it really is a WOOFER). Back to Khorns and no more MWMs for me. Much better bass in my room

Did you offset the phase rotation built into the xover? Time alignment and phase alignment are intertwined....changing the time alignment changes the relative phase. All the khorn networks introduce extra electrical phase so that things line up acoustically (even though the time arrivals aren't the same). Moving individual drivers without changing the phase will introduce a big notch around the xover frequency.

ClaudeJ1:

Basically the MWMs is a 6-foot horn, while the Khorn is an 8-foot horn, so they go lower.

The khorn is a 5ft horn (58" or whatever).....and corner loading benefits for the khorn will also apply to any other horn in the same corner. To claim the Khorn gets an additional 4ft from the wall, but the MWM doesn't is inconsistent logic.

Sure, the khorn was designed to work in a corner and the MWM was designed to not require a corner, but that's irrelevant....it just means the MWM takes care of most of its corner itself. The Jub LF was designed to work without a corner, but it also benefits from being in a corner....just like the khorn, and just like the MWM and any other undersized mouth horn.

The reason I bring it up is because the MWM is way more efficient at 40Hz than the Khorn.

ClaudeJ1:

So if the K-33 is the best woofer for hi-fi

Best? I don't think so.  Maybe best bang for the buck.

ClaudeJ1:

while maintaining ALL of PWK's principles of good sound.

I take issue with that comment because if you maintained "all" of his principals, then you would end up with the exact same designs.....or you would be saying that PWK didn't know how to best implement his own principals.

The crux of the matter is you want to justify your sound by trying to associate it with PWK. If you notice the changes made to the Khorn over the years, and then PWK's (and Roy's) achievements with the Jubilee (which PWK felt was better than the khorn), then you should notice that you're moving backwards relative to PWK's progression.

Why can't it just be that you enjoy your system? Why try to justify it with ancient theory?

mikebse2a3:

ClaudeJ1:

Not really. They are best suited for disco speakers because of the large hump at 50-60 Hz. before they plummet at 48 hz. or so with room gain. Basically the MWMs is a 6-foot horn, while the Khorn is an 8-foot horn, so they go lower. Yes I PEQ'd the hump flat, but the Khorn bass is deeper and more defined, without a doubt. Extensive listening of all kinds of test material and measurments bears this out.

I really don't see were you get the 8ft horn length for the Khorn. It is of an "approximate" finite length of 58" and then the mouths must be corner loaded(ie:natural or false) to take advantage of 1/8 space loading gain which serves to extend the systems response in a room. Of course even 1/8th space loading(ie:tri-corner) isn't a totally valid way to look at things in an actual enclosed space/room were other room boundries come into play.

 That is the approximate "effective" length when you work 4 feet of coner plus 4 feet of folds. 1/4 wave of of a 32 foot bass note, which Klipsch has always claimed the Khorn could do................35 Hz. Both horns are/were working in the same room so going beyond the front corners represents roghly the same load at those low frequencies. Remember I'm rolling off the bass section with an active/discete sub amp/Xover at about 180 Hz. NOT 400-500 Hz. like the Khorn or Jubilee. I'm paying close attention to the NATURAL linear part of curve of all horn/driver combos and achieving a pretty smooth response in the room at the single sweet spot. Since I'm the only serious listener, I'm not concerned about what is sounds like anyhere else in the room, where the listening is just background or exercise music anyhow. If the midrange is "where we live" according to PWK, then that 180-6Khz range is being handled by 2 straight axis horns. Piano, sax, voice all sound amazingly detailed, dynamic, and distortion free at any level. I'm not PEQing the crap out of my large format drivers like everyone else who chooses the 2-way route. You all know who you are. Not saying that is a bad choice, just not my choice. All passive Xover users are doing the PEQ there (very expensive and electrically lossy) and ignoring time delay, since there's no way to adjust for it if you respect the aesthetices of the "treble horn on top of bass horn in the corner" which I don't do........my setup looks almost ridiculous and ugly but it's all about the sound.

 

ClaudeJ1:

So if the K-33 is the best woofer for hi-fi, and I have a choice to put it in an 8-foot horn vs. a 6-foot horn, the choice is clear. Remember that I only used either one blow 200 Hz. where the curves and the 1/2 mouth spacing behave best. Above 200 Hz to about 1Khz, a straight axix CD horn with a phase plug and an 12" driver does a way better job than either a Khorn, MWM, Jubillee, or LaScala........I have had them all over the last 32 years.

Hey Claude unless you bought some Jubilees I believe you shouldn't include the Jubilee in your statement of having had them all? Unless you have actually used a Jubilee/K402 (for example) in your own room your conclusion is undetermend at best.

Also keep in mind that even though a straight horn with a single mouth could out perform a design like the Khorn or Jubilee (which is a bifurcated and folded horn design which was to acheive specific design goals) in a certain frequency range under certain limited conditions you must still mate it with other horns and integrate it with the room which then has it's own compromises so ultimate performance in context of the total loudspeaker system and room integration changes everything as it has since PWK first designed the Khorn.

My components are integrated well enough to present reasoanble imaging with far greater dynamics and impact of a 1977 Khorn, which I lived with for 30 years. The guys that are dinking around with whatever Xover upgrades to stock Khorns are kidding themselves if they think they are making a huge improvement. Large format drivers and bigger horns are the answer. It took PWK 50 years to incrementally improve the bass section with the Jubilee bin, but the Khorn bass is still a very good performer. Also PWK had a large format driver on top of his Jubs, with the EQ handled by a horn never produced. What makes the Jubille so much better is the large horn/large format driver on top in whatever form of Xover/PEQ you wish. My joining this group about 3 years ago is what started this new quest. This is where the journey took me. You are right about the JUBILEE, I have not owned one and I left out the "EXCEPT FOR THE JUBILEE" in my statement........sorry about that!

There's no doubt that Jubilee bins might marginally improve the bass in my setup. I can't even buy the lumber for Jub clones for what I paid for my Khorn clones, and they are Walnut veneer!! Keep in mind that Rigma's premium passive networks costs the same $$ as all of my 7.1 channels in my setup. So if you thow in performance per dollar in the equattion, I win. Also keep in mind that I have sold off my original 3-channel array (La Scala Center with PWK's resistor box for mono) and built this 7.1 system of mine from that money alone.....bang for buck. Attempting physical alignment happens to be a cheap/easy way for me to achieve much better than the 5 millisecond or so delay between the K400/K55 and the Khorn Bass Section I lived with for over 30 years. Large format top ends alow me to even listen to rock music without the stridency of that little 5/8 throat in the K400. This system handles anything I can throw at it with less than 2 watt peaks in the bass section (I have 100 W available/ch. so Grasshopper, don't give this stuff about not enough headroom, I got it covered.

 

ClaudeJ1:

So in my evolution in the last 2 years with the MWMs, I discovered that 4 was unnecessary (way overkill indoors) and busted down to 2 with a little extra gain....very good. I just improved it again by going back to a Khorn clone bottom with Crites woofers (old K-33's for all practical puposes). The false corners are 4 feet FORWARD of the natural corners where all of the other 3 voice coils are jammed into. This is BY FAR the best sounding setup I have ever had, with careful matching of all components has taken me over 2 years to evolve while maintaining ALL of PWK's principles of good sound.

Claude your conclusions about why you prefer what you do(between Khorn and MWM) are in question in my way of thinking because you really aren't comparing apples to apples IMHO for several reasons but one "very important one in particular". Your room's acoustics are unique like everyones and depending on were the mouths of the horns are physically located in this room will determine what your end results will be at any particular listening location in that room. Even if the two horns acoustical responses were identical once you changed were the mouths of the horns are located in the room what you perceive/like will be determined by this fact.

Taking all of the "romance" out of it, they are simply both exponential approximations with the same woofer and similar room gain. Even Jim Hunter told me that the MWM and Khorn are "basically the same thing." The MWM evolved out of a need for a PA speaker that didn't need a corner and was much easier to build than a Khorn. The mouths are approximately in the same place in my room, nothing much changed there. My next step is to build two 13 foot long horn subwoofers that will room load and EQ to 22 Hz. and get rid of all direct radiators in my HT setup. I can do that for about $800 and get $500 for my VMPS units, so it's a $300 upgrade with a lot of sawdust.

ClaudeJ1:

This is BY FAR the best sounding setup I have ever had, with careful matching of all components has taken me over 2 years to evolve while maintaining ALL of PWK's principles of good sound.

All designs are a balance in compromises! I would differ with you on following all of PWK's principles of good sound and call your attention to the fact that PWK always expressed and designed for as few horns/crossover points as possible to acheive each systems design goals. To overlook this is to overlook the history and orginal design goals of the Klipschorn. The fact that his personel decision and design goal for the improvement of the Klipschorn was a return to a 2-way Horn system is a clear indication of his principles for sound and what direction improvement would come in and it wasn't to complicate and make it a 4-way design and then try to make all 4 Horns acoustically sum again.

Well that statement simply isn't true. We are all in the Pro Loudspeaker arena here with large format drivers, including you. The Jubilee bin is in the Theater line. the TSCM was nothing but a black Khorn bass bin with built-in corners and a beefier woofer married to large format tops. The MCM 1900 evolved into a 4-way system, and the final/ultimatedesign (some of Roys's best work with PWK's blessing) was the KP-600 modular system which is 5-way and considered the best by many. The flagship of the company currently (it's in the LOBBY of Indy HQ for a reason) is a 4-way, so your comment is simply not true. If I see an economic and sonic benefit to reducing the number of components in the future, I will do so, but I sure as heck won't do it with 2 berrylium diaphagmmed drivers that cost more than my entire used system and still need a ton of PEQ to work right.

Anyway I'm really glad you enjoy your system Claude because that is very important goal in this hobby!

Thank you, I do enjoy it very much, and I do appreciate your point of view, sincerely.

mike tn