I have been trying to record the Line Out from an Akai EWI4000 breath controller. The signal is weaker than the headphone Out mini-1'8" . Even with the patches volume at highest level -30- there is barely anything. I am using a Behringer FCA202, they claim the driver for Mac is Core Audio and I can adjust the bit depth and sample rate in the Audio/MIDI set up. The Behringer has a a/d converter and I wonder if the Firewire protocols on my ancient Mini PPC are even seeing the incoming digital audio. I use a USB mic and it works fine.
I saw something on the Apple site about possible incompatibility of the old Firewire protocol and a new set called SDK24-anyone else recording digital audio through a Firewire powered hub? The La cie FW HD boots and performs quite well, although i did get an error"-2" a few times. the Midi connection works as I do get a track of Midi data. I have tried it in an aggregate device and by choosing the behringer's digital audio output manually but nada. A better audio/Midi interface would be better but if the PPC G4 1.5ghz can't handle Firewire i might as well forget about FW and try to find a USB interface.
Please, any suggestions will be greatly appreciated.

AFAIK, the "older" firewire issues are more a question for G3 and early G4.

Now, what bothers me the most is the firewire hub, have you tried without? If it's just for a try, and a couple of tracks, you can use your system drive, the point is to find out if the hub is the issue.

The "-2" error is a finder, a DAW error? it's been a long time since i've seen it, in the finder it was troubles with the memory under classic. Now if it's the DAW, it's something else.

I wonder if your akai doesn't need a preamp, anyway its certainly not a normal level for line out.