Doesn't seem to matter where we sing. When I HAD an upper register, and sang baritone notes, and she tried alto, it STILL didn't work. Think beer over cheesecake, think pizza with a scoop of pistachio ice cream on top, think fingernails and a chalkboard. It wasn't the notes, it was....Hell, I don't know what it was. It's like two sine waves that cannot overlap. (By the way, I liked Pavoritti and Sting, TBPL - *g*)
And leeneia, we been trying for 30 years! But we finally gave up. Some things just don't blend. (Thanks, Lady Jean... it's nice to hear someone else has the same problem.)