Unibody MacBook Pro vs. MBox 2 Pro (how I beat Audio buffer underflow -6085)

[Arthur Nascimento]

I have a shiny new MacBook Pro @ 2.44GHz with 4GB of Ram and a 250GB 7200RPM Drive Running OS X 10.5.6. Add to that an MBox 2 Pro running with ProTools 7.4.2. I have all of the Factory Pack 2 plugins updated for OS X 10.5.x. and Pro Tools 7.4.2. My Media Drive is WD My Book Studio 750GB @ 7200 RPM with an Oxford 934 Chipset (not fully qualified but not really forbidden either).

As Per Digi’s recommendation I used the 800 connection between the drive and the laptop and then it was daisy chained with a 800/400 cable to the MBox.

(http://www.digidesign.com/index.cfm?...5&itemid=36933)

“The FireWire 800 port on these computers is backwards compatible* with FireWire 400 devices, but requires one of the following configuration options:
FW800 port —> FW800 Drive (912 or 924 chipset) —> Out FW400 port on Drive —> Pro Tools LE FireWire audio interface”

When I put all of this together all I managed were hours of Audio buffer underflow -6085 errors.

So then I remembered this little bit if information...

(http://www.digidesign.com/index.cfm?...5&itemid=23112)

“FireWire/1394 Cards for Laptops

Maximum Track Count With Mbox 2 Pro
In order to achieve close-to-full track count with DV Toolkit 2, Music Production Toolkit, Music Production Toolkit 2, or Complete Production Toolkit when using the Mbox 2 Pro on the MacBook Pro, the following configuration is required:
SIIG FireWire 2-Port ExpressCard
Part Number: NN-EC2012-S1
Connect the Mbox 2 Pro to the built-in MacBook Pro FireWire port
Connect 2 or more qualified FireWire drives (daisy chained) to one of the ports on the SIIG FireWire 2-Port ExpressCard”

... just happened to have one around and plugged the audio interface into it and everything worked. I have more testing to do over the weekend but so far it looks bullet proof. I'm going to try keeping the firewire 800 connected to the Media Drive as that seems to make sense but I really don't think it matters that much.

I am convinced that the configuration Digi recommends above (FW800 port —> FW800 Drive —> Out FW400 port on Drive —> Pro Tools LE FireWire audio interface) wont work...