One of the tips I got from talking to Lexicon tech support was to (not) set the Alpha as the default playback device in Windows for recording or playback. (set the motherboards primary audio instead) and completely de-select the Alpha as far as Windows is concerned.

Then in the host program, RealBand in this case setup the Alpha as the audio in and out and try again to playback media in RealBand.

You may want to use headphones directly plugged into the Alpha to cut out any other gear that could be problematic on the output path. As well, utilize your VU meters in RealBand and let us know if you have signal bouncing or not on the output side.

Thanks!