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Hi everyone! Im an experienced Mac user in need of help resolving FireWire device issues.

I received my 27 i7 iMac a couple of weeks ago running 10.6.2. After a long process of migrating over from my 9+ year old Dual 500 MHz G4 PowerMac tower, I was excited to set up two 1TB drives inside an OWC Mercury Elite Quad-Interface Dual HD enclosure via FW800. I then daisy chained my Focusrite Saffire 10 audio interface (FW400) to the HD enclosure via a FW800 to FW400 converter cable. To reiterate:

i7 iMac (FW800 port) --> OWC Mercury Pro Quad-Interface Dual HD Case with 2X 1TB drives (FW800) --> Focusrite Saffire 10 audio interface (FW400)

Although a lot of people may disagree, I wasnt concerned about having my FW800 HD setup drop down to FW400 speeds because of the slower audio interface. I have read enough about the 1394 FW protocol and its ability to use something called beta clouds, allowing both FW400 and FW800 daisy chained devices to operate at their maximum speeds. So far, so good. The drives are reading/writing data fast.

As many studio audiophiles have said, you should separate your audio recordings and projects from your startup disk. Ive done so. However, call me naïve, but I did not imagine that every time my external drives read or wrote data, my audio interface would go into a state of distortion (like raising the gain on a track as high as it can go). When the activity of the disk drops below a certain level, the audio interface usually switches back to clean pristine audio. I am experiencing this within a studio environment (Logic Pro 9) and with simple CoreAudio iTunes playback via my audio interface. How is this possible? Am I doing something wrong or is there a blatant limitation with the FW chipset Apple is using for their single bus in the new iMacs? If anyone can provide me with a solution or a convenient work around (i.e., not telling me to turn off my hard drive and connect my I/O directly into the iMac every time I start up Logic), I will provide you with a craft beer or a thank you (you pick). :-)