How do you test a potted crossover?

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My 60's vintage Electro-Voice speakers have fully potted crossovers at 3600 hz, from the SP12 alnico woofer to the compression driver/tweeter. Same tweeter used for years on many Klipsch products.

There is an annoying, harsh sound in the mid and upper mid-range at times that causes me to turn the volume down. At first I suspected the woofers were bad, but I no longer believe that. I'm not talking about deafening levels either. And, I find those tweeters to be strident.

I'd like to keep, and upgrade these speakers for my workshop, but have no idea how to test the X8 crossover. An EV expert told me he rarely sees units go "bad". These are over 50 years old, so I find that hard to believe. Both speakers are doing the same thing.

Can anyone give me some clues to get me going in the right direction?

Joined 2011
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potted crossover

Rayma: Thank you for that info. I make the same mistake every time I refer to those EV speakers....they have a T25A driver, which is a mid driver. Hence the X8 crossover at 800 hz.

These speakers really confuse me, because they were offered as DIY, and factory built. Mine are factory, but I suspect that someone changed them. The driver the T25 is mounted on is small, and there is a larger opening blanked off on the baffle board for what I thought was for a mid-range horn. The tweeter would likely use the 3600hz crossover, the X36.

I have to open these up again soon.

Thank you for your info. Those pages you linked to are very helpful. I have a balanced stereo 3 way electronic crossover, so I think I'll bypass the crossover, and see what happens going active.
potted crossover

Part of the mystery is solved. The wires for the T25 and horn combo in one speaker (mid-horn) were loose, and the horn had was physically loose and buzzing against the baffle.
The other one was fine.

There never was a tweeter in either speaker. My lack of knowledge of EV speakers led me to believe the mid horn was larger than it actually is. Insulation was covering up part of the horn, which I refastened.

I read that the SP12 is full range alnico 12", and can run out to about 8khz. I don't understand why some of the same speakers used the SP12 out to 3600, and crossed to a T35 tweeter, yet mine cross to the mid horn at 800hz. (??) This follows the literature Rayma pointed me to.

I think I'll try my JBL 2404H with these and see what I think.
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