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librosa.interval_frequencies

librosa.interval_frequencies(n_bins, *, fmin, intervals, bins_per_octave=12, tuning=0.0, sort=True)[source]

Construct a set of frequencies from an interval set

Parameters:

n_binsint

The number of frequencies to generate

fminfloat > 0

The minimum frequency

intervalsstr or array of floats in [1, 2)

If str, must be one of the following: - ‘equal’ - equal temperament - ‘pythagorean’ - Pythagorean intervals - ‘ji3’ - 3-limit just intonation - ‘ji5’ - 5-limit just intonation - ‘ji7’ - 7-limit just intonation

Otherwise, an array of intervals in the range [1, 2) can be provided.

bins_per_octaveint > 0

If intervals is a string specification, how many bins to generate per octave. If intervals is an array, then this parameter is ignored.

tuningfloat

Deviation from A440 tuning in fractional bins. This is only used when intervals == ‘equal’

sortbool

Sort the intervals in ascending order.

Returns:

frequenciesarray of float: The frequencies

Examples

Generate two octaves of Pythagorean intervals starting at 55Hz

>>> librosa.interval_frequencies(24, fmin=55, intervals="pythagorean", bins_per_octave=12)
array([ 55.   ,  58.733,  61.875,  66.075,  69.609,  74.334,  78.311,
        82.5  ,  88.099,  92.812,  99.112, 104.414, 110.   , 117.466,
       123.75 , 132.149, 139.219, 148.668, 156.621, 165.   , 176.199,
       185.625, 198.224, 208.828])

Generate two octaves of 5-limit intervals starting at 55Hz

>>> librosa.interval_frequencies(24, fmin=55, intervals="ji5", bins_per_octave=12)
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 ])

Generate three octaves using only three intervals

>>> intervals = [1, 4/3, 3/2]
>>> librosa.interval_frequencies(9, fmin=55, intervals=intervals)
array([ 55.   ,  73.333,  82.5  , 110.   , 146.667, 165.   , 220.   ,
   293.333, 330.   ])