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impedence curve for Khorn


dhsettim

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Hi ya all, I understand from Al Klappenberger's posts that his ALK crossover presents a near constant 8 ohm impedence to the amplifier, but is anyone able to provide an impedence curve for the Type A crossover when fitted to the Khorns. I have both crossovers (as well as the original Type AA) and was interested in a comparison. Thanks, tim

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Here's a set of curves publised in AUDIO magazine. As you can see the impedance goes to over 40 Ohms in the middle of the squawkers range (bottom curve)! This is becasue of how PWK used the autotransformer. The impedance goes up to allow a smaller value series capacitor to limit the low frequencies to the squawker. I his day, big value caps cost BIG bucks or were simply not available. This is no longer the case. The big loop in the top curve is the K33 resonating below the woofer horn cutoff. This is to be expected.

BTW: A perfect constant impedance would be a dot at 0 on the reactive scale (vertical)and 8 on the resistance (horizontal) scale.

Al K.

post-2934-1381925795032_thumb.jpg

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Tim,

I do not have an actual curve of my network in a Khorn as I have Belles. I did point-to-point measurments with an impedance bridge when I had my "A" type in my unmodified Belles several years ago but I did not make a curve. I have better equipment now, but my Belles are modifed, so I can no longer do a ligitamate curve. The response will be quite similar to what I show for the network alone on my web site except the woofer's deep low frequency response will look like the article. Upper bass will be less "reactive". The drivers are quite good resistive loads to the network over then usefull range making the curves for network alone pretty close. One thing is for cure though. The big 40 Ohm area in the squawkers ranges is gone!

Al K.

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Thanks again Al,

I'll go back again to your site and have a look.

Would you say that it's due to this reduction in 40 Ohm level in the squawker that gives your crossover its major advantage?

I am trying to figure out why PWK and Bruce Edgar both apparently prefer the Type A. I have built both,and am currently using the Type A, so must get the guys around one afternoon and do a comparison. I'll let ya know what the general consensus is down here in the south.

best wishes

tim

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Hi Tim,

The Type A and the simpler crossovers like the Type AA sound better because there are fewer components in the signal path to change the signal. Of course, they are a trade-off between that and power handling and driver protection.

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Guys,

One reason a "simple" network will often sound better is becasue it is less critical. It's hard to screw up the design because it so simple. Adding just a few additional parts incorrectly doesn't help much. The "AA" is an example of sticking a few extra parts in the "A" tweeter filter. It was done to protect the tweeter, not to sound better!

I can't point to one single reason why I claim mine is better. It's simply a complete and proper "multiplexer" rather then 3 stand-alone filters stuck together. The extreme-slope networks I am promoting are ANYHTING but simple but sound better becasue the sounds from adjacent drivers so not interact with each other. "Time alignment" becomes unnecessary.

I also believe that some amps do not operate well into odd-ball impedances. A flat resistive load of 8 Ohms is the best load to put on any amp. Some amps don't care what load you put on them. Others do!

Al K.

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----------------

On 9/20/2004 1:39:08 PM Al Klappenberger wrote:

Guys,

One reason a "simple" network will often sound better is becasue it is less critical. It's hard to screw up the design because it so simple. Adding just a few additional parts incorrectly doesn't help much. The "AA" is an example of sticking a few extra parts in the "A" tweeter filter. It was done to protect the tweeter, not to sound better!

I can't point to one single reason why I claim mine is better. It's simply a complete and proper "multiplexer" rather then 3 stand-alone filters stuck together. The extreme-slope networks I am promoting are ANYHTING but simple but sound better becasue the sounds from adjacent drivers so not interact with each other. "Time alignment" becomes unnecessary.

I also believe that some amps do not operate well into odd-ball impedances. A flat resistive load of 8 Ohms is the best load to put on any amp. Some amps don't care what load you put on them. Others do!

Al K.

----------------

"Less is more until less is just less." -- Mark Deneen

Obviously what works "best" is going to be system/room/ears dependant. It's easy to see how in varying circumstances each might come forward in its own way and be preferred over another. For example, with its slight drop in output to the tweeter, I always thought the AA might be preferred by Solid State users, or high SPL listeners. I think the Type A with a high bandwidth amplifier might be a little "spitty".

I've only heard the ALKs once -- on some Klipschorns being driven with some vintage Pilot push-pulls -- and thought it sounded marvelous.

It's just my opinion, but I think SET amps, push-pulls not using any feedback, and/or senstive to changes in impedance -- should probably be ALK'ed. Solid state users who want to go to the ALKs better make sure they're using GOOD solid state.

As for me, I kind of prefer networks with at least 50 parts in them.9.gif

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"Less is more until less is just less." -- Mark Deneen

Another similar saying is 'Make everything as simple as possible, but no simpler.' -- Albert Einstein

Also worth keeping in mind that just reducing parts count in a crossover makes the crossover itself somewhat simpler, but it makes other factors in the system more complex.

A more 'complex' crossover, such as Al's ES series, makes other parts of the system design 'simpler.'

There is no free lunch...

Shawn

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Dean, that makes good sense.

I agree and I'm using ALKs with GOOD solid-state...

Also, the "number-of-parts-per-dollar" ratio has to be considered an important design criteria... for instance, look at the 70's gear with the highest "knob-to-dollar" ratio, and that's some good stuff (NOT)!2.gif

DM2.gif

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