Designed to work with the new Power Mac G4, the Apple Pro Speakers connect to Apple's proprietary mini jack speaker on the G4 system using a single cable. The Power Mac G4 delivers 20 watts of floor-thumping sound (10 watts per channel) to the speakers. The Apple Pro Speakers provide excellent sound quality with a frequency range of 70 hertz to 20 kilohertz. And if you're an audiophile who likes to feel your music through the soles of your feet, you'll 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.