Diki just for the heck of it...I stuck the thumb drive into the pa800 tonight on stage before I started to perform ......loaded an Mp3, and while it was playing there is a small tempo window in the the song title display.....I just tapped it to highlight it and started to turn the wheel as the tempo increased smoothly WITHOUT A GLITCH in real time and subsequently decreased it the same way....very impressive!!....I now have to figure out how to transpose the mp3/wav as you requested ,,,,,then I'll try to record some short demos ....more to come.