runtime/Lib/site-packages/noisereduce/generate_noise.py

import numpy as np

# from https://stackoverflow.com/questions/33933842/how-to-generate-noise-in-frequency-range-with-numpy
def fftnoise(f):
    """
    """
    f = np.array(f, dtype="complex")
    Np = (len(f) - 1) // 2
    phases = np.random.rand(Np) * 2 * np.pi
    phases = np.cos(phases) + 1j * np.sin(phases)
    f[1 : Np + 1] *= phases
    f[-1 : -1 - Np : -1] = np.conj(f[1 : Np + 1])
    return np.fft.ifft(f).real


def band_limited_noise(min_freq, max_freq, samples=1024, samplerate=1):
    freqs = np.abs(np.fft.fftfreq(samples, 1 / samplerate))
    f = np.zeros(samples)
    f[np.logical_and(freqs >= min_freq, freqs <= max_freq)] = 1
    return fftnoise(f)