Hi all, I've been browsing through the internet regarding the problem with resonance on the new Mac Pros (maybe on the Power Macs as well), where the hard disks vibrate/resonate and thus making the entire Mac Pro case producing a very annoying sine wave resonance sound. I've found a couple of forum threads with suggestions on how to reduce/eliminate this sound, but none of the methods did work for me. Some methods required material that many people don't have at home, and neither did I, so I can not tell you if those methods were any good. Anyway, since many people (especially owners of Samsung hard disks) are experiencing this problem, I thought I'll share my solution as well since it only requires material most of us already have at home. Source Of The Problem If you remove a HD from one of the bays and hold it on each of the long sides with your thumb and middle finger respectively, you will hear a short vibrating sound when you quickly tap the rectangular metal plate of the metal drive carrier (the metal plate covering the back of your hard disk, in other words the metal plate that is visible when you open up the hatch of your Mac Pro). This vibrating movement will be constant when the hard disks are spinning, which produces an almost constant vibrating sine wave sound. Solving The Problem Materials needed: towel + scissors Cut out a piece of towel with the same width as the rectangular plate on the metal drive carrier. The length should be approximately 15 cm (6"). Now fold this towel piece in order to create a "towel block" which will fit in the space between the metal plate and the back of the hard disk. It shouldn't be possible to insert the "towel block" inside that space without a little force. If it isn't thick enough, it won't dampen the vibration. I had to force it in with the help of a pen, however not too forcefully as I didn't want to damage the hard disk. If you feel you might damage your hard disk, reduce the thickness of the towel block a little bit and try to insert it again. If it's thick enough, you won't hear that short vibrating sound when you tap the metal plate anymore. Now simply insert the drive carrier back into the bay and enjoy a silent Mac Pro experience I use all the four drive bays, with four 300 GB hard disks, and the vibration sound is completely gone. I hope this works for you too!