I know someone who cannot seem to 'hit' a note, even when he is PLAYING the correct note on an instrument...he says he has some hearing loss in middle registers, but I think it may be more than that....

...as to memory, it seems that we ARE wired very differently...some people remember sounds, and can learn song choruses instantly..(and ROUNDS!...bah, humbug!)..I need to see them in print first. Then I can do pretty well...and when I sing, I often 'see' the printed page in my head..including songs that finish at the top of the next page. I can 'usually' transfer this to 'aural' memory patterns after awhile, and simply sing as if I'm speaking.

Just think about those translators at the U.N., hearing one language and remembering a sentence with inverse word order, and putting into another language with 'normal' word order...all done 'on the fly'..now THERE is wiring!