The mel scale (after the word melody)[1] is a perceptual scale of pitches judged by listeners to be equal in distance from one another. The reference point between this scale and normal frequency measurement is defined by assigning a perceptual pitch of 1000 mels to a 1000 Hz tone, 40 dB above the listener's threshold. Above about 500 Hz, increasingly large intervals are judged by listeners to produce equal pitch increments.
- ^ Stevens, Stanley Smith; Volkmann; John; Newman, Edwin B. (1937). "A scale for the measurement of the psychological magnitude pitch". Journal of the Acoustical Society of America. 8 (3): 185–190. Bibcode:1937ASAJ....8..185S. doi:10.1121/1.1915893. Archived from the original on 2013-04-14.