Peavy XR400B speakers squeaking?

[Admpres]

Hey guys, I just recently found that the speakers to my old peavy mixer's (70's) are making a really obnoxious squeaking noise. I haven't been able to find anything visibly wrong (other then a few loose and rusted screws). Does anyone have any Ideas? Any help would be much appreciated.

https://soundcloud.com/admpreston/squeaky-speakers

[B-string]

Sounds like a blown speaker. Do you have another cab to test the amp part through?

[Admpres]

Yep. The head is fine. I've never had the speakers up all that loud though, mainly used for some jazz gigs, and that's about it.

[B-string]

If you can remove the grill on the speakers gentle push evenly on the cones they should move freely without any rubbing. If one does not that one is blown.

[Admpres]

They move perfectly, no rubbing at all. So, I don't think that's the problem.

[B-string]

Pull the speakers and check all connections for being clean and tight. It the wiring, jacks clean, speaker cables plugs are clean, then the speakers would need to be sweeped with a signal to locate a possible voice coil or cone separation (speaker repair shop).