In this Demo, Robby, a Yamaha rep explains that he creates User Harmonies because he finds the factory presets distort. In another of his demos he created a midi track to trigger the harmony. The other demos he has have the distorted phasey sound. These two where he has put in the time to improve the harmony yielded a reasonable result. However Digitech or Helicon give you good results without having to mess around. Robbie also says singing too close, having keyboard speaker volume to high and a less than perfect mike will also yield poor results. Sounds like way to much work for a singer who needs good harmony available at the touch of a footswitch.