librosa.hz_to_fjs(frequencies, *, fmin=None, unison=None, unicode=False)[source]

Convert one or more frequencies (in Hz) from a just intonation scale to notes in FJS notation.

frequenciesfloat or iterable of float

Input frequencies, specified in Hz

fminfloat (optional)

The minimum frequency, corresponding to a unison note. If not provided, it will be inferred as min(frequencies)

unisonstr (optional)

The name of the unison note. If not provided, it will be inferred as the scientific pitch notation name of fmin, that is, hz_to_note(fmin)


If True, then unicode symbols are used for accidentals. If False, then low-order ASCII symbols are used for accidentals.

notesstr or np.ndarray(dtype=str)

notes[i] is the closest note name to frequency[i] (or frequency if the input is scalar)


Get a single note name for a frequency, relative to A=55 Hz

>>> librosa.hz_to_fjs(66, fmin=55, unicode=True)

Get notation for a 5-limit frequency set starting at A=55

>>> freqs = librosa.interval_frequencies(24, intervals="ji5", fmin=55)
>>> freqs
array([ 55.   ,  58.667,  61.875,  66.   ,  68.75 ,  73.333,  77.344,
    82.5  ,  88.   ,  91.667,  99.   , 103.125, 110.   , 117.333,
   123.75 , 132.   , 137.5  , 146.667, 154.687, 165.   , 176.   ,
   183.333, 198.   , 206.25 ])
>>> librosa.hz_to_fjs(freqs, unicode=True)
array(['A', 'B♭₅', 'B', 'C₅', 'C♯⁵', 'D', 'D♯⁵', 'E', 'F₅', 'F♯⁵', 'G₅',
   'G♯⁵', 'A', 'B♭₅', 'B', 'C₅', 'C♯⁵', 'D', 'D♯⁵', 'E', 'F₅', 'F♯⁵',
   'G₅', 'G♯⁵'], dtype='<U3')