How the sound parameters are calculated


  • f : spectrum frequency
  • a : spectrum amplitude
  • F0 : fundamental frequency
  • F : harmonics frequencies
  • A : harmonics amplitudes
  • n : number of harmonics
  • m : buffer size


Timbre equation

Sound width

Sound Width equation

where k0 and kn are the indices of the first and the last harmonics having an amplitude greater than a threshold.


The brightness is calculated as the spectral centroid normalized by F0 :

Brightness equation

Tristimulus Coefficients

The Tristimulus coefficients are calculated as energy ratios of the first harmonics :

Tristimulus equations

Tonality Coefficient

The tonality coefficient is calculated as the Wiener entropy :

Tonality coefficient equation


The inharmonicity is calculated as the sum of harmonics frequencies deviations :

Inharmonicity equation

Refer to the bibliography for references.