Buzzing squawker

[ben.]

I posted in 2-ch, but this is probably where this should go:

I listened more critically to my '56 University corner horn (AKA the largest patio speaker on town) last night, and noticed a rattle from the squawker. It was not distortion per se, but a vibration. The driver is a PAH (what a monster! about 3x the size of a k55 or ID30) mated to a Cobreflex horn.

I removed the driver and it sounded like there was a pebble inside when I shook it. I took it inside and ran it off the HK430 with no horn. The rattle was still there. The diaphragm looks OK from the front, but I'm not sure how to get it apart to conduct further examinations. There are 4 screws on the face of the compression chamber, but it still won't come apart with those out. Any diagnoses/suggestions?

Thanks in advance

Ben

I know somebody had a similar problem round here, but I couldn't find the thread.

[Geo1]

Hi: You may be thinking of the buzzing I had with the tweeter in my Quartet. It was buzzing between 135Hz and 145 Hz, but that turned out to be loose nuts holding the horn structure to the driver. I don't think I can help with your situation. Sorry.

[ben.]

No, but thanks. I found the thread, but I still can't figure out how to get the PAH apart. There are 4 machine screws from the front. I've got those removed, but the thing is still solid. Short of just hitting with a big hammer, anyone have any suggestions? I think the driver is kind of rare. I don't see it in any University literature in www.hifilit.com. I thought maybe someone would have some general advice on how to disassemble it, as I have never had to get inside a compression driver.