mel

A unit of subjectively estimated pitch. A sine wave with a frequency of 1000 hertz, 40 decibels above the listener’s threshold of hearing, has by definition a pitch of 1000 mels. A sound that a listener judges to be 2 times the pitch of a sound with a pitch of 1000 mels has a pitch of 2000 mels; a pitch judged half of a 1000-mel tone would be 500 mels.

The table below shows the pitch in mels of a pure sine wave at a few frequencies. Do not conclude from this table that there is a one-to-one mapping between the dominant frequency of a musical tone and its pitch. Although frequency is the most important factor in determining pitch, the sensation of pitch is also influenced by other factors.

Frequency (hertz)	Pitch (mels)
20	0
40	46
80	126
100	161
400	508
800	854
1000	1000
2000	1545
4000	2250
10,000	3075

IEEE Society on Acoustics, Speech, and Signal Processing.