(Johan Sebastian Bach - Goldberg Variations, BWV 988: i. Aria - Glenn Gould (1981)
(Horizontal Scale: logarithm of frequency (from 2 octaves below middle C to 3 octaves above it)
(Verical Sale: square root of mean intensity - A = 440 Hz (equal temperament assumed) )
( http://www.youtube.com/user/inwit )