So, I have a USB microphone and I want to connect its output to the input of another USB audio device (A Roland VT-4 Voice Transformer). Not physically, but through my MacBook.
I am no expert on Mac USB audio, however, I have spent a day or so trying: aggregate devices, Jack and VB-Audio virtual cable.
Sending system audio out through the vt4 and then using the processed sound (eg recording in Quicktime) is easy, however, I simply cannot connect my USB mic output to the VT-4's USB input.
OMG, how hard can it be?