Looking for a vocal harmonizer that works

[George]

Have a theory that a vocal harmonizer would make the remaining echo on a Vogone treated song blend in as part of the harmony, if distinguishable at all.

Realize this would not be practical in all instances, but there are many songs that would do just fine sung in harmony with one's self.Does anyone out there know of a vocal harmonizer that really works and does not wind up sounding like the Chipmunks?

Thanks,

George