Greetings,
Anyone who claims to have very good relative pitch can test themselves
extensively with GNU Solfege. Even better, try your ears against Lars
Edlund's Modus Novus.
re: Perfect (aka absolute) pitch : I've worked with a guitarist here who
has demonstrable perfect pitch. He was most definitely born with it, he
has no training in music other than his own self-instruction. He's an
excellent mimic, he can play other people's solos note for note, and he
has about 200+ songs memorized, including the non-guitar parts. That
said, he can't improvise worth a damn, he's no writer, and his
musicality extends to only classic rock and other straightforward rock
styles, i.e. he has no interest in other musics.
Best,
dp (who swears by Modus Novus and Modus Vetus)