Pyaudio for external interfaces (Mac OSX)
A couple shots in the dark - Verify if you're opening the device correctly - looks like the Fireface can be both half or full duplex (pref pane configurable?), and pyaudio apparently cares (i.e. you can't specify an output if you specify an input or vise versa.)
Another thing to check out is the audio routing - under /Applications/Utilities/Audio Midi Setup.app, depending on how you have the signals coming in you might be connecting to the wrong one and not realizing it.
Using Python and PyAudio, I can't seem to record sound to a wav file from an external audio interface (RME Fireface), but i am able to do so with the in built mic on my iMac. I set the default device to Fireface in System preferences, and when i run the code, the wav file is created but no sound comes out when i play it. The code is as given on the PyAudio webpage. Is there any way to rectify this?