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JBL LE25 and LE5-6 polarity questions

fredjones

fredjones

Active Member
I am building a crossover for my JBL L36 speakers I recently acquired. The crossover design (by Jantzen) has these two speakers being hooked up reversed polarity. I have been doing some searches and it seems that JBL manufactured these speakers to have the polarity reversed from what you would normally think. Anyone have experience with these old JBL drivers?

Thanks
 
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I don't have experience with those speakers specifically, but if you do a Google search for: JBL L36 schematic, the first link you will see is to a pdf with the schematic. It doesn't look like they are reversed to me.
 
Did some research over on audioheritage and it seems that some vintage JBL drivers including these were "negative", that is applying a positive voltage to the positiver terminal causes the diaphragm to move inward. Convention would have it move outward.
 
fredjones said:
I am building a crossover for my JBL L36 speakers I recently acquired. The crossover design (by Jantzen) has these two speakers being hooked up reversed polarity. I have been doing some searches and it seems that JBL manufactured these speakers to have the polarity reversed from what you would normally think. Anyone have experience with these old JBL drivers?

Thanks
Click to expand...

The woofer as well. No confirmed reason has been determined why JBL used that standard.

Not sure what you mean by a "Jantzen" crossover. Is this a custom or rebuild of the original design expressly for the L36?
 
This drove me nuts on complex 4-way. These speakers were obviously touched by the wrong person multiple times.

Everything was was easily confirmed in a few minutes until I got to the tweeter.
Do not test tweeters with a battery, so.....
The general consensus was "wire it to whatever makes you happy". I wasn't happy with the answer, but couldn't hear any problems either.

A few weeks later I found a reasonable answer.
I used white noise with ears level between the tweeter and mid until the phase with the most favorable balance is found. It turns out that the "balance" confirmed my suspicions on how it should be wired.
 
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