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Driver Polarity Question


rmaustin

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Hi to everyone,long time reader,first time to post to this forum.I've been a Klipsch man since the first time I heard a pair of heresy's in 1979.I have a pair of 1980 Heresy's as well as a 1984 pair of cornwalls.Like alot of you I feel that there is no other speakers except Klipsch.I use Klipsch in my home theater and my computer(Promedia 2.1).I also have built several cornwall replica's over the years for myself and also for a friend or two mainly in the 80's and early 90's.My question to anyone that could help is this,Im in the process of building another pair but on a larger scale of the cornwall design that will house 18 inch Eminence drivers.In the early to mid eighties I use to buy alot of my drivers and horn's from a company called speakerlab.This company had alot of the same horn drivers that Klipsh uses in thier Heritage line.I've got an old pair of midrange horn drivers that I bought from speakerlab that Im using as my midrange in this project Im doing.I've used this same driver in the other cornwall replica projects that I've done over the years.Last night I took the back off one of the heresy's and one of the cornwall's and removed the k-55 driver form the horn lens and compared it with the speakerlab midrange driver.They are an exact match in everyway except for the company label on the back of the magnet.I guess Klipsch and Speakerlab bought these from Altec,EV,etc.Here is the kicker,In comparing the two drivers,both drivers have the markings for the connections as 1 and 2 instead of + and -,I noticed on the k-55-v driver that the number 2 connection had the red painted dot indicating the positive connection for the crossover.All these years I have used these speakerlab midrange drivers they have never had a red painted dot on any of them,I assumed that the number 1 connection would be the positive and connection 2 negative.If this is true,I have connected all of these speakerlab drivers up with the polarity incorrect.All of these I've built have always sounded great but if polarity is wrong on these midrange drivers,thats a problem and the performance would suffer.Can any of you shed any light on this problem.Again there is no doubt that these are the same drivers down to every marking.Does Klipsch change the polarity on these drivers for crossover purposes?Please Help

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Randall,

The polarity of the squawker mianly sets the response at the crossover. On the Khorn, that's 400 Hz. When the phase is reversed a drop-out may happen right near the crossover. You can't actually hear the polarity unless the left and right speakers are reversed with respect to each other. That shows up a goofy stereo imaging. Just be sure both speakers are wired the same way. The polarity of the tweeter is virtually meaningless becasue of the wavelength of the highs. You really need instruments to tell what the correct phasing is.

Al K.

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Polarity of drivers is an interesting study. An old EV document that I found said that polarity should be established on each driver such that a positive signal to the voice coil causes outward deflection of the diaphragm or cone. Then I started checking some Klipsch K-77M tweeters and found that the diaphragm is just as likely to go in or out with a positive signal. Even with the positive side of the diaphragm connected properly, the deflection still depends on the magnet being oriented right. I found that of the ones I had when I did that test, lots of the ceramic magnets were installed backwards. Granted, mine was a small sample of perhaps ten K-77Ms and might not in any way be representative. If that sample is representative, a lot of people are listening to out of phase tweeters. This situation should not be possible on the alnico magnet tweeters, just on the ceramic.

Guess I had better go ahead and tell how to test for this. Someone is likely to ask. You disassemble the tweeter and place the magnet assembly on a table with the magnet gap facing up. You then place a bare diaphragm in the correct position with voice coil in the magnet gap. Take a 1.5 volt battery and apply the DC voltage to the diaphragm with the positive wire from the battery to the red side of the diaphragm. The diaphragm should jump off of the magnet assembly if it is right. If it is pulled in toward the magnet assembly, it is wrong. I am not suggesting that anyone do this, you will stand a good chance of damaging the diaphragm when you take the tweeter apart and you would need a loose new diaphragm handy for the test, not the one in the housing that you take off.

Bob Crites

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aren´t there supposed to be little red dots painted near the positive temrinakls on klipsch drivers? or at least that is what I was told...I remember playing around for days after installing my new crossovers trying to get the phase right...when they are right the stereo imaging improves...I remember going through a check list one by one until I found the right combo...grrrr....tony

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Bob,

I don't think the PD5 diaphragms I put in the four K55Vs that I refurbished

were marked at all. I checked the polarity by using a battery (1.5V) just as

you did. Part of the confusion about phasing standards is that some drivers

have the diaphragm behind a tunnel and the polarity is reversed compared to

the ones like the K55 where the diaphragm is on the other side of the magnet.

I never bother to think this out but the standard needs to be given as the

polarity necessary to move the diaphragm toward or away from the phase plug.

JBL, for one, is reversed compared to other makes.

I really don't think it is that important though. My experiments tell me that

you ear is deaf to that kind of phase. It's only important at the crossover

where two drivers have to blend their sounds together. If the phase is

reversed the two may cancel. Even then, if the path length difference is such

that the delay difference result is a 90 degree shift it won't make any

difference at all! Of course the crossover network causes even more phase

shift unknowns. The bottom line is it really doesn't matter so long at the

left and right speakers are both set the same way.

Al K.

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Al,

The Atlas diaphragms for the K-55V and the EV diaphragms for the K-77 both have red marks on them that indicate the positive side. You could do either of two things to reverse the polarity. You could reverse the wires, or you could turn the magnet over. Both do the same thing. Not a problem with the alnico since they were magnetized at the factory after the magnet assembly is put together. In all likelyhood those are all the same and being all the same is all that matters. The ceramic magnet models are another story. The K-77M can have its magnet put in with south pole up or north pole up. Works either way but would reverse the action of the diaphragm with respect to the marked polarity of the diaphragm. As I was saying earlier, I know that at least some are reversed so in some cases with all wiring the same, the pair of tweeters will be phased oppositely.

Bob

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Wow - sounds like a discussion that happens with JBL. Much like Lucas Electronics (anyone here ever own a 60s or 70s british auto?), general standards don't seem to apply. And bless JBL for changing it mid stream for some components so that you really don't know without testing or using a rather large crib sheet. I had wired tweeters out of phase for about two months in a couple of test boxes and as AL indicated - My ear could not hear a difference.

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  • 15 years later...
11 hours ago, Mechanic58 said:

If you look at the old speaker lab crossover diagram for their original crossovers they tell you to hook the positive to The terminal marked one in the negative to the terminal marked two

This is a 15 year old thread.

 

Welcome to the forum.

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  • 2 weeks later...

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