I hate to be a pest on this issue after all this discussion; but it’s still not clear to me what the VL3X is capable of doing. I’m sure it will track a guitar or midi signal very well to generate vocal harmony. However, before investing that kind of money, here’s what I’d like to know about the audio input: Let’s say you take a fully mixed BIAB track as a wav file and plug it in on a thumb drive. Say, the song is a standard tune, like Misty in Eb. You plug in a mic, make the proper adjustments, start play on the track, and begin to sing (no guitar or anything else plugged in, in this example). Will the VL3X generate appropriate vocal harmonies from the audio track alone, while singing, with no other instrument providing the chords? If it will do that accurately without glitches, then, that’s more than amazing and will get my attention for sure. If anyone has used the VL3X exclusively with the audio input, I’d love to hear about it.