Hi Jerry. I've noticed that Yamaha's VH is pretty acceptable with the female voice. I worked on line with a woman who was tweaking VH2 to improve it. She sells vocal paks suited for different voices. I sent her raw unaffected voice samples of me singing and through her magic she got some pretty decent harmonies.
If I had a PSR S 970 instead of PSR S750 I would have taken her up on an offer of the appropriate voice pak for my range in return for me helping her out.
For some reason the VH2 doesn't have a "duo setting" hence no Don an Phil so I'll just stick with my trusty Digitech Vocalist 4.

https://app.box.com/s/vmg6qaj790fns2j8d0jxvffub3q3u4pq