(My sincere apologies for the lack of posts...almost a month! =[ I guess I have reasons...I got a job, and a MacBook. I'm not totally slacking off; I've got some articles planned which I hope to write soon.)
(NB 2...This is a nerdy post. Regular readers don't have to read this =])
On Mac OSX (particularly 10.5) occasionally there will be horrible static in recordings and playback from a USB audio device.
I may have found a solution. (Leopard 10.5.5, fwiw)
The problem, according to some people in a different forum, may be related to the clock source of the USB box.
To fix this, I went into Apps/Utilities/Audio Midi Setup. In the Audio menu there is an entry "Open Aggregate Device Editor". Click that.
In the dialog, click the + button at the bottom of the list, which was empty on my machine.
It will add a new device and in the bottom pane all the sound devices in your computer will show up. Only check the ones you want to use (USB audio). Then use the Clock radio button and select one of the USB devices as the clock source (I used the output).
Now set your default input and output to "Aggregate Device".
In the output options on the Aggregate Device (lower pane of the main window in Audio MIDI Setup) I set the output rate from 8 bits to 16. I don't know why it would default to 8 bits unless Apple lives in 1986. Go figure.
That fixed it for me. YMMV, as always.