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CD Tractrix Design?


Klewless

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To keep the record straight.. The K402 is a square Conical horn with a modified tracktrix mouth,,, To see a accurate square tractrix horn refer to the photos from Klipsch museum University of New Mexico... Voight horn design

Is this the one?They also have one at the Klipsch Factory Museum. It is one of my faves.

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Thanks GIL!! It seems I had seem those threads but I was hoping there was more in gramaphone. That is where I got the dates to search. If you want a better scan the Grammophone website has all their magazines online. Just register and search. I have a saved search in ebay just in case one of these early magazines comes up for auction.

Those Voigt ads are incredible!!!!!!!!!

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To keep the record straight.. The K402 is a square Conical horn with a modified tracktrix mouth,,, To see a accurate square tractrix horn refer to the photos from Klipsch museum University of New Mexico... Voigt horn design

Nope! The K402 is rectangular, not square.

past comment from Roy to a post on the forum about the K402; " actually, i call it tractrix, modified tractrix to be more exact because i modify the tractrix equation to get good polars using straight wall sides. if fact, i check each of the tool profiles before the tools are harden so that i can make sure that the curve has remained in tact. in fact i had a vendor do me a "favor" one time, he took out a "bump" in the four sides of the horn. i told him we want those bumps please put them back!!

Basically it comes down to this if you believe constant coverage over a given horns designed bandwith is an important design goal (and there is excellent research supporting constant coverage as desirable in loudspeakers for home use in particular of which Toole's research comes first to mind) then a horn based on modification of the tractrix expansion like the K402 is an excellent option.

mike tn

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Beautiful, and ahead of it's time, for sure. But not constant directivity.

Being ignorant of some of these things, I'll admit I would love to do a side by side listen with a CD horn, EXP horn, Tractrix horn, heck, even a rubber duckie horn where all the horns are constructed to cover the exact same bandwith (ie, swap out the K400 in my LaScalas or the K402 in the Jubilee)

Edit for clarification. What I mean to say is swap out my K400 in my LaScala for a CD horn to put back in it, or a Tractrix horn or a rubber duckie horn to go back into the LaScala, covering the bandwidth of the K400. Likewise, swap out the K402 with these other various designs so I could hear how they sound on top of the Jubilee in a side by side mannor. I was not inferring to swap out the K400 and K402 with each other in any mannor. I already know how that can sound!

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Re: What makes some tractrix horns suitable for HF?

From the pictures on the forum, it looks like the K402 is a tractrix mouth coupled to a conical throat.

Bill Woods, horn designer forYorkville sound, built this tractrix horn in 1975:

page10-1005-full.jpg

Some remarks of his:

I’m often asked how horns differ from one another, and also how different types of horns differ in sound and design, such as exponential, tractrix, and new versions of these which carry the names of their designers. I’ve put together some observations, backed up by actual frequency response curves and measurements, so that people can decide for themselves what types of horns would work best for them.

For the past 30 years I have designed loud speakers for professional applications and more recently for home HiFi. While designing at Yorkville Sound and in the course of my career, have built and tested numerous exponential and tractrix horns. This includes hybrid profiles using a tractrix and a conical which were created to fulfill specific tasks. In professional audio, horns have to work as intended. They cannot be of unlimited size - in fact, there exists an obvious commercial advantage to building the smallest horn to do a given job well. Tractrix or exponential horns are rarely used in professional applications where clarity and coverage are an issue.

The tractrix profile has been used in commercial products and in DIY. All exponential, and tractrix horns tend to beam as they go higher in frequency due to the squeezing of the side wall of the horn. This results in a "honky" sound and some of the high frequency information is lost, when listening off axis. This is the case no mater what type of mouth correction you might use. The tractrix profile itself is a form of mouth correction.

I can, however, suggest a simple way to make some experiments for yourself, to see how horns differ from each other in a very rudimentary way. Choose a compression driver, and make a number of very short horns of only 4-5 inches in length ---really horn adapters-- for your driver.

The most critical part of a horn is the first few inches. This is often over looked. Start with a section of straight pipe. Listen to that. It will be very loud, and very colored. Next, try an exponential horn of the same length, then a tractrix - they will be progressively less colored. Finally, try the conical section. It will be the most natural sounding and uncolored.

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For those wanting to try a good, inexpensive conical horn, suitable for a two-way (Jubilee, Cornwall, or dual 12s like the CF4, KLF30), look at this $58 horn:

http://www.loudspeakersplus.com/images/XT1464.pdf

The 1/4W cut-off point of this horn is 340hz, and is said to be useable above 500hz. For prosound use an 800hz crossover point is recommended for pattern control and power handling. I would imagine it would sound fine at 650hz/24dB for home use.

Note: Don't be alarmed by the 60° pattern on this horn. Horns of this type sound so smooth off-axis that the 60° seems to be fine for home use. I am buying a pair for some Beyma CP-755, only $179.50 (no VAT for export).

http://profesional.beyma.com/ingles/pdf/CP755Ti.pdf

ex-VAT is GB122=USD180

http://www.bluearan.co.uk/index.php?id=BMACP755TI&browsemode=category

"I'm not sure I totally agree with the test....are you holding the flare rates constant, or setting a fixed mouth area? "

Doesn't matter.

The point is to listen to different throat expansions using small horns of different types. You cut them off high enough to avoid the natural cut-off point of the horns, so you are just evaluating the throat transition. Some throat transitions measure good, but sound poor (just goes to show we don't know what to measure).

"The most critical part of a horn is the first few inches."

This was my quote of Bill Woods, but I totally agree with it. At one time PWK made a similar statement, almost the same exact wording.

Bill Wood's site:

http://www.acoustichorn.com/

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Mike,,,True its not square,,,But the mouth is not rectangular in ratio either,,,, I dont think you could hear the difference between the k402 and a Kazoo,,In that mirror,d listening room.. The reason for the tractrix mouth on the conical horn is to smooth out the discontinuity at the mouth edge of the horn.

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Mike,,,True its not square,,,But the mouth is not rectangular in ratio either,,,, I dont think you could hear the difference between the k402 and a Kazoo,,In that mirror,d listening room..

I see your up to your old tricks Maron..!

I hope your having fun because you evidently don't have anthing better to do than talk nonsense and try to stir up crap.

Happy Thanksgiving to Everyone and Especially Maron Horonzak!

mike tn[:D]

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OK... What would be a better driver ??? that does not cost an arm and leg

If you move away from the titanium diaphragm, to a phenolic, you will have to go to a three way.

I know that Dennis indicated it would be hard to beat for the price.

Bruce

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OK... What would be a better driver ??? that does not cost an arm and leg

If you move away from the titanium diaphragm, to a phenolic, you will have to go to a three way.

I know that Dennis indicated it would be hard to beat for the price.

Bruce

Hard to beat what ? the K69 ?

How about something with a magnesium diaphram ?

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