The mel scale was derived by asking listeners to double perceived pitch

Evidence

The scale thus obtained is called the mel scale, and the name of the unit is the mel, which comes from the English word melody. It turns out that when subjects are asked to double the pitch they double the frequency, on average, for frequencies below about 500–1000 Hz (Fastl and Zwicker, 2007). — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1092

Categorization

• DEFINE: Defines the mel scale, the perceptual pitch scale underlying mel-frequency cepstral coefficients used widely in speech recognition.
• XREF: The mel scale’s derivation-by-pitch-doubling connects to the earlier JND/psychoacoustic materials and is the perceptual basis of MFCC features in audio ML.