It looks like I am no longer locked out from replying. Unfortunately the forum ate my prior message so I'll try to recreate.
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I was able to make the playback work, however the balance of the volume between the audio file from the USB stick and the piano itself is way off. The file is way too loud and the piano too soft. I tried adjusting the relative volume under SONG --> MIDI Volume and Audio volume, but even at MIDI set a 1 and Audio set at 127 it is still way off. Can you offer recommendations on how to fix this problem?
Thanks.