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Frequency measurement of 'Polyresonant 4-cavity box, Paul Klipsch?


johnyholiday

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Many thanks JohnnyH.

To answer Dr. Who's question. The Karlson (as shown in the drawing) was just a box with a cut out in front which resembled a cross section of a horn. All sorts of outrageous claims were made about it, and it had a substantial following. Naturally there was, in fact, no technical merit to the claims. There is only so much you can do with a hole in a board.

It is interesting to see that PWK measured it.

Best,

Gil

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PWK most likely measured it because it was his competition at the time.

The Karlson was quite popular, being that it produced prodigious bass for the size of the box (see attachment) from an article posted by Gil.

There are many different patents that use the exponential (Karlson) slot as a port, etc. Many different inventors evidently found there was something to it, regardless of current popular opinion. Watch for a commercial comeback, Karlsons are popular with the DIY crowd, too.

However, although resurrected by the DIY crowd, the Karlson enclosure died out like the JBL Hartsfield (which sounded quite good); it may be that it cost more than the simpler reflex designs which were also smaller ( a desirable attribute for domestic use). Perhaps the pressures of the market place killed it, not that it lacked performance. I would really like to hear one with good drivers in it someday. I believe that they used a coaxial driver.

DM

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I wouldn't expect PWK to promote anything from other competitors, of course, and the circumstances behind the testing is certainly suspect. In Dope from Hope, he reported that (assumption of Speakerlab K is made by myself) clones of the Khorn from the Pacific Northwest couldn't go below 70 Hz (or was it 80?). I've heard them for myself and that is just absolutely, patently untrue. It was a ver batim copy of a Klipschorn, why wouldn't it go below 70Hz?! Oh, please!

So much for PWK's rigorous testing of compeditive products! Don't believe everything you read, even if from PWK - remember, he had his reasons!

Well, enough of that...

Here's the plans for the 15" driver version of the Karlson cabinet, which has a following even today.

DM

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Like I was implying, if it was so bad, why isn't it completely dead?

Answer: there IS something to it... either that or all these people are crazy.

I must admit that it is a nice looking thing that one doesn't necissarily want to cover up with a grill cloth. Perhaps that could be the attraction?

This is a recent design for a 12" driver off the web.

DM

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D-Man is dragging me back into the argument, if only as a source of the article. Good job.

I believe the best analysis would be the basic driver and box tested with and without the front chamber and cut out. It could be that the effects are peaks in response we see. Then we'd have to decide which is better.

In fairness to PWK, I think he picked up on an overstatement by SpeakerLab that the midrange went down to 70 Hz and his comment was "why didn't they use it as a woofer." The graphs of the SK response by him did show some healthy bass which could only have come from the woofer horn.

Gil

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I once heard a fella's Karlsons with co-axial 15" Evs, they sounded pretty good. They probably would have sounded good in a regular box too though. But as has been mentioned there is a Karlson Kult out there, the guys that made the Exemplar horn wrote an article in Sound Practices touting Karlsons as subs with VOTs.

An astute old ex WE horny that some of us know is intriqued with the Karlson.

Hey Gil, tell us about the RJ.

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The Karlson is a type 6B bandpass box (nomenclature from BassBox pro).

The rear cavity is vented into the front cavity, the front cavity is vented to the outside via the slot. In a regular BP6B the HF response rolls off sharply due to the hemholtz behavior of the port. The Karlson slot is more of a broadband port, in part due to the angle of the baffel board WRT to slot, and the width of the slot. These really affect the HF response of the Karlson. The deep nulls in the response above 200hz are due to side-to-side resonances of the parallel walls in the front cavity.

I have modeled the K-15 in BassBox and the impedance peaks agree with a real Karlson (impedance data provided by Fred Ireson).

From 50hz~250hz the Karlson (with a proper driver for the box) has more output, and smoother output, than a similar sized horn (about the same bulk as just the bass horn section of a LaScala).

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Ok, I found the PWK quote about an "imitator" on the West Coast (I assumed Speakerlab) not going below 70Hz... its from Speaker Builder magazine.

However, since PWK didn't name any names (and he NEVER did BTW),

it is left to us to figure it out. This is an aspect of PWK worthy of much respect.

As another note, Speakerlab never got sued by PWK, nor anything else, so that might indicate that he wasn't talking about them...

DM

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