Help, Is it possible to fix a tweeter?

[paysonmark]

I have a tweeter from a 1973 optimus7 that is not blown but its sound output is less than 50% or more of the other tweeter. I recapped one xover, I tried both tweeters on the same xover so there would be difference in caps,vinductors and wires. It has a paper cone and Alnico magnets. Any help would be gratful

 

[slimecity]

So you have tested both tweeters on the same over and you have found that one tweeter is still quieter than the other one?

 

[paysonmark]

yes, exactly

 

[CheeseofBorg]

Have you tried swapping the speakers at the receiver outputs?

 

[paysonmark]

Yes, before and after the xover upgrade. And both tweeters measure 6.7 ohms

 

[LexDM3]

If the tweeters use ferrofluid, there's an excellent chance that the old fluid is sticky and is reducing the movement of the tweeter, hence lower output. I've seen this with a few ADS tweeters. Parts Express sells ferrofluid and it's not too tough to do.

 

[paysonmark]

IDK, they are from 1973

 

[swechsler]

My guess would be damage to the voice coil, either something stuck in the gap or the VC form is warped or bent. Theoretically anything is repairable, but looking at a picture of these tweeters, it will probably be very difficult to do without damaging them, since I assume they are sealed in the back. Domes are easier because the faceplate/diaphragm can usually be separated from the magnet by removing screws. You would need to remove the cone from the frame without ripping it, then remove the spider, also without damage. Very difficult, even for a pro. IMO you're better off looking for replacements on eBay. If you can't find them, if you can figure out the specs, there's at least a half-decent chance you can replace them with something better.

Remove one tweeter and post some pics, front and back. Make sure any markings are legible in the photos.

 

[paysonmark]

paper cones and sealed back (stamped metal frame)

 

[toxcrusadr]

You're a subscriber, post a Wanted in Bartertown for a tweeter. Pics help because some of us have orphan tweeters laying around.

 

[Tom66]

I’ve seen somewhere that it’s possible that the voice coil wires have been overheated. The wires on the voice coil then get that the coating on the wires get to hot. Then the coating melts or burns. The wires make contact. Than you get a tweeter with a lower impedance as the other good tweeter. And less efficiency. I would dismount the tweeter and inspect the voice coil. Before that, measure the impedance of both tweeters.

Tom W.

 

[paysonmark]

I’ve seen somewhere that it’s possible that the voice coil wires have been overheated. The wires on the voice coil then get that the coating on the wires get to hot. Then the coating melts or burns. The wires make contact. Than you get a tweeter with a lower impedance as the other good tweeter. And less efficiency. I would dismount the tweeter and inspect the voice coil. Before that, measure the impedance of both tweeters.

thanks , make sense 7.1 vs 6.8 ohms

 

[toxcrusadr]

That's not much of a difference really. Quite common to see 10% difference in DCR between drivers - at least on mass market speakers where they weren't carefully matched to begin with.