melfrequency

Melfrequency is a term sometimes used in psychoacoustics and audio signal processing to refer to the frequency dimension expressed on the mel scale. It is not a separate physical quantity, but rather the mapping between hertz (Hz) and the perceptually motivated mel units used in mel-scaled representations such as mel spectrograms and MFCCs.

The standard conversion between Hz and mel is widely employed: mel m = 2595 log10(1 + f/700), where f is frequency in Hz. The inverse mapping is f = 700 (10^(m/2595) − 1). These equations describe how numerical frequency values in the mel domain relate to actual sound frequencies. The mel scale emphasizes perceptual differences in pitch, being approximately linear at low frequencies and logarithmic at higher frequencies.

Applications of mel-scaled representations rely on the concept of melfrequency to organize spectral information. Mel spectrograms, MFCCs (mel-frequency cepstral coefficients), and related features are common in speech recognition, music information retrieval, and audio classification. By using the mel scale, these methods aim to align computational analysis with human auditory perception and to reduce dimensionality.

Notes and limitations: the term melfrequency is not uniformly standardized, and in formal literature the emphasis is often on the mel scale or mel-frequency axis rather than a distinct unit called “melfrequency.” Different implementations may adopt slightly different constants or frequency ranges, influencing the exact mapping.