Apple has posted Mac Pro Audio Update 1.1 (http://support.apple.com/kb/DL1042), which addresses an audio anomaly that some customers may hear coming from inside their Mac Pro computer when using FireWire audio devices. This update is for Mac Pro (Early 2009) computers running Mac OS X v10.6.3.
Mac Pro Audio 1.1 is a 515KB download. It requires Mac OS X 10.6.3 or higher and can be obtained via the Software Updates component of Mac OS X’s Systems Preferences app.
