I know this is an old thread, but these JBL Pro III speakers are worth listening to -- even today! They're awesome.
Pro III replacement woofers are available directly through JBL. I've done this... but it required phone patience as I dealt with customer representative research.
The woofers are available on Amazon: search "JBL Factory Replacement Woofer, 4 Ohms, Control 1, Pro III, C1003"
I have my desktop PC driving a Maverick Audio DAC, an Adcom 5300 80-Watt amp, and JBL Pro III's with newer JBL shielded woofers. They work and sound great!
