Cubase 5 Pitch Shift sounds lousy in general

[Paul]

I had a conga player lay some tracks on my
current hit single, and due to my inexperience,
I didn't have him tune his set to the song.

So now I have a bass conga, that is acceptable
as-is, but that is a tiny bit out of tune with the
rest of the song.

So I tried the pitch-shift in Cubase, and although
it does work, it unfavorably affects the rest of the
kit. There are different qualities to the algorithm,
from "preview" to the highest quality, but even at the
highest quality, it makes the rest of the track sound
lousy. There's just some things you cannot fix in the
mix, unfortunately.

Actually, the raw track still works musically, because
the congas being slightly outside of the rest of the band
actually helps bring it out of the mix more.

I would assume most pitch shifters are similarly limited,
in that you cannot alter the original track too much
without making things sound totally unnatural....