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Cross Section Of a K-Horn


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JBL(and others) produced speakers that were based on PWK's folded corner-horn designs...the Hartsfield ( I thought it was Hartsford?)was one of these...and JBL was licensed to produce it. Go to hifilit.com...look at the period literature there about Klipsch and read the fine print on it...it will list those companies which were producing under license from Klipsch at the time.

Throughout the 1950's and into the 1960's PWK offered many of his speakers in kit form and also licensed them out to other manufacturers. He also sold plans to his designs for the DIY folks...with listings of appropriate drivers for them.

As for cross-section k-horns, a number of them were built at the plant for audio conventions and dealers and such...with 1/4th of the bass bin cut-away. There was ALSO at least one k-horn built out of different colored plexiglass panels, so that you could see how the different planes of the folded horn worked. I always thought the plexiglass k-horn was pretty cool!! Smile.gif

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This message has been edited by HDBRbuilder on 08-04-2002 at 10:34 AM

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Hi HDBRbuilder

The JBL Hartsfield was based on the patented design of William Hartsfield and therefore not licensed from Klipsch. To say that it was influenced by the Klipschorn would be an understatement. Nonetheless, the horn path and overall geometry were unique as shown here:

Hartsfield Profile

As to sonic differences, I cannot comment. The Hartsfield is rare enough that I have yet to come across one in person. Due to their rarity, the going rate for used systems on Ebay these days is around $15,000/pr as shown here:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1370944882

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Don McRitchie

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Lansing Heritage Website

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the Hartsfield is nothing like the Klipschorn, it WAS however a statement system to compete with the Klipschorn. They both use the the corner to form the last bend in the horn, but the folding is completely different (one is bi-frucated!).

the Hartsfield is rare but the Stan White 4D is the *rarest* of them all.

This message has been edited by John Warren on 08-04-2002 at 12:02 PM

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I bet that if you pull up the Hartsfield patent and look at its refernce cites you will find the PWK's cornerhorn patent as one of them. This speaker was basically an enlarged version of the bottom half of a k-horn bass bin with a different sound path ONLY at its point of ORIGIN...but still very similar in design to the lower pathway of the k-horn in every other way...EXCEPT the Hartsfield also had sides integral to it so that it need NOT be in a corner in order to use the walls of the corner as an extension of its bass horn. It was also built using heavier materials for its stock in the bass bin section.

Just as on the Klipsch MWM woofer for its MCM system, which is patented by Gary Gillum and PWK, but which was BASED on the design of an old RCA theater horn in the old Hope, Arkansas movie theater...just because one gets a patent on something doesn't mean it is one's original idea!!

Modifications to a device previously patented MAY allow one person's original patent to become a part of another's patent, as long as the earlier patents are cited as references in the patent application...this has always been a "grey area" in the patenting process....since it is the DEGREE to which the changes are made that decides whether a patent will, in fact, be issued for a similar device already patented. Sometimes it can be nothing more than just a cosmetic change to a device that allows another patent on it!

Even PWK's patent on the k-horn bass bin has referenced previous patents and articles listed on it.

Bye the way...If you read Bill Hartsfield's patent, you will find that the bass bin is NOT the object of the patent application...the object of the patent application(which is WHY it was issued) is the CONVERTIBILITY of the cabinet for different uses of different high-frequency drivers and combinations in its top-end section...using an adaptor set-up...kinda like how PWK not only had a patent on his cornerhorn design, but ALSO had a LATER design patent for its LATER cabinet cosmetics and appearance from the outside.

In other words the patent for the Hartsfield had little to do with its bass bin design...wonder why?

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This message has been edited by HDBRbuilder on 08-04-2002 at 12:28 PM

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Never accused anybody of being blind...and even though I have to wear bifocals...I can easily see the OBVIOUS..."hmmm...how do we get around that darned PWK cornerhorn patent? Well, we can add some sides to it...and we can put in a few curved pieces at the outer bends of the horn...and we can just copy the LOWER section of it...and we can change the throat part and initial soundpath for the first few inches...but they may still catch us on it...how about we go the CONVERTIBLE cabinet route? That way those clowns at the patent office won't pay so much attention to the similarities of this thing to that darned PWK cornerhorn!! Yep, that's the ticket...CONVERTIBILITY IT IS!!" Smile.gif

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If u look at the pic of the Klipschorn cutaway you'll see that the back plate is totally solid with vents on each side. My K-horn has an opening with a screen on the back plate and also has the side vents. Builder do you know why they changed the design? Was it a radical improvement or a slight modification? Also, do u have a better cutaway you can post?

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Trader,

Here is how the K-horn bass bin works...the driver fires through a slot(throat)in the front of the motorboard to which it is mounted. The soundpath is split at that point by its hitting a wedge-shaped piece that is horizontally mounted on the rear side of the front panel of the cabinet, then the soundpath goes both upwards AND downwards (bifurcated pathway)along the backside of the cabinet's front panel through channels that are running up and down and are formed by the "skeeter wings" mounted to the back side of the front panel of the cabinet and the motorboard(picture yourself as the woofer as you stand in a corner facing AWAY from the corner...you yell into a horn that splits into two horns right in front of your mouth, with a horn running upwards, and another running downwards here)...then, the soundpath reaches the top and bottom of the cabinet where it is directed to the REAR of the cabinet by the upper and lower "wing assemblies"(picture the horn running up in the front then bending and running back over your head to your rear...and the horn running down in the front then bending and running underneath you to the rear...both of these heading toward the room corner behind you...and both of these CURVING TOWARDS each other as they run behind you until their mouthes become just one mouth right in front of the corner)...then the soundpath hits the tailpiece and is reflected forward to EACH SIDE, and along each wall from the corner(picture this horn that has rejoined into one behind you splitting yet again and now becoming TWO separate horns as these two horn mouths come back around you on each side of you...firing forward)...the uniqueness of this system is that the initial paths of the sound are travelling first, up/down, then over/under to the rear, where they join and then reflect forward, and again split into two horns ROTATING 90 DEGREES to fire FORWARD again with their two mouthes ending on each side of the starting point of the soundpath. That's the k-horn bass horn!!

Now...picture yourself standing the same way, BUT the horn you yell into DOESN'T split in front of your mouth, but instead JUST goes downward at a slight angle for a few inches, then straight downward...just like on the bottom part of a k-horn...in effect you are just doing away with the initial split of the k-horn path.....then when it fires under you just like before, instead of it linking up to a top part back behind you, just let it reflect at the rear all by itself, and THEN SPLIT as it, too, rotates 90 degrees and fires forward along each side all by itself...and you have the Hartfield...pretty simple!!...half a k-horn along its initial path, BUT as it fires forward again, it is just like an ENTIRE k-horn!! Smile.gif

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This message has been edited by HDBRbuilder on 08-04-2002 at 05:18 PM

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The first link shows another drawing of the lower section of a Klipschorn. But I'm not sure how accurate it is. The other links are just interesting reading about the Klipschorn:

http://community-2.webtv.net/KerrB/VINTAGETUBEAMPHORN/page4.html

http://www.audioimport.nl/klipsch/11a.htm

http://www.stereotimes.com/speak080301.shtm

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Here is a cartoon of the Klipschorn, it is not entirely accurate but serves the purpose.

K-horn.jpg

Here is the Hartsfeild, the horn that PWK *should* have patented. It avoids the problems of the bi-frucated throat and is easier to model.

horn_path_small.jpg

BTW, the Hartsfield is much closer in its design to the National Catenoid corner horn enclosure first developed by LEE in 1952.

The Klipschorn, like all folded horns, generates

harmonic distortion. The bi-frucated path just makes things worse (how do you know the pressure field is actually split in half equally??). Modeling it requires a leap in faith ("zany" rubber throats!!!)

I like the Klipschorn bass unit, faults aside but

it certainly isn't the end all.

This message has been edited by John Warren on 08-04-2002 at 07:47 PM

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John, when you talk of modeling the horn, do you mean some numerical solution to the Navier-Stokes equations? I have been out of that business for some time, but hear that there have been great advances in numerical solutions. What with all of the computing power at our finger tips now.

J Norvell

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Pretty dense stuff!

I still can't picture the Klipschorn or the Hartfield.

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Speakers: JBL HLS-610

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Yes, it sucks, but better to come. KLIPSCH soon! My computer is better than my stereo!

For JBL related subjects and more fun, click: http://www.audioheritage.com

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jnorv-

underling principles of mordern horn theory are well described in

(1) V. Salmon "Generalized Plane Wave Horn Theory", in J. of Acous Soc. of Am., Vol 17, No. 3, Jan 1946

and

(2) L.L. Beraneck, "Acoustics", McGraw-Hill, (1954)

Any good university tech library will have these.

JW

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djk,

Interesting & thankyou. A while back I was working with the idea of folding the LaScala again. I have it drawn in full scale on a sheet of plywood. My drawing looks alot like the one you posted.

Then,when I first saw the pictures of the Jubilee I had a feeling that was what they did.

I'll have to get back to work on it and do a little more of the math. At least now I feel that I'm moving in the right direction. I want do design it for two 15" woofers.

Q.

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Q-Man

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