Yea, whatever it is its High.

Yeah, RealMusician, I would probably agree with you on "Diamonds and Pearls." The low D is really more of a hint than anything (low D played by bass in line "you will hear me say...that I will never run away..." implies Prince's D). Other than that, the Eb's in the songs you mentioned are about his max (or min, or whatever).

See, I never know whether to take whistle register into account. This Australian guy who sang backups for Mariah Carey could sing every note she could in whistle register, just like she does. He even hit a high B above C alt altissimo (a maj 7th above the piano's highest C!). It was pretty crazy, although it sounded more like radar than anything. I'm pretty sure only bats and dogs could really hear it! His voice was otherwise a baritone-bass, and his lowest note was the C two octaves below middle C (a minor third below Prince's lowest Eb). Techincally, his range would be just short of seven octaves.

That's very extreme. I'm not sure where I heard some sound clips of him before. His name is Adam Lopez, I think. On the same website, I heard that guy, I don't remember his name, but he's one of those Russian Basso Profundo singers, hit a G two and a half octaves below middle C. That was the strangest sound I've ever heard. It was like a growl, but yet still a low G.