Made for Mac...
iSub
iSubs are perfectly compatible with 333 mhz Powerbooks and above running OS 10.1 and above.
Click here for the iSub page. Near the bottom you'll find the compatibility listing.
... with Pro Speakers
Apple says: "
Youll be delighted to hear that the Apple Pro Speakers can be used with the Harman/Kardon iSub Subwoofer system for an even richer audio experience."
Click here to visit the Apple page. Keep in mind it's referring to the Cube speakers similar look to the Pro Speakers - maybe thats the source of the confusion.
Minijack Verification
Good point beez7777... behind the Airport window, and the PC Card slot and vent louvers...you'll see a headphone minijack line, however, Apple says that "
Currently, Apple Pro Speakers should only be used with the new G4-based iMac or the Power Mac with minijack.:
FYI
Just for your information... in case anyone else is wondering, here's what else is on the back of the Titanium Powerbook...
Ask your source that told you there was a compatibility issue for more info. Follow up here if you can so others can verify the rumor. Be sure to tell your source to visit
http://www.MacRumors.com ... the best source for the truth about Mac rumors