For more information about the examples, such as how the Python and Mojo files interact with each other, see the Examples Overview

BuchlaWaveFolder

This example demonstrates the Buchla 259-style wavefolder distortion on a sine wave.

The Buchla Wavefolder is a classic wave-shaping synthesis technique that adds harmonic complexity to audio signals by folding the waveform back on itself when it exceeds certain thresholds. This results in a rich, complex sound often used in electronic music synthesis. Derived from "Virual Analog Buchla 259e Wavefolder" by Esqueda, etc.

Use the BuchlaWaveFolder_AD version for Anti-Aliasing (ADAA) and Oversampling. The ADAA technique is based on Jatin Chowdhury's chow_dsp waveshapers.

It is recommended to plot the output waveform to get a sense of how the wavefolding process alters the sound.

Python Code

from mmm_python.MMMAudio import MMMAudio

# instantiate and load the graph
mmm_audio = MMMAudio(128, graph_name="BuchlaWaveFolder_AD", package_name="examples")

# to hear the version without Anti-Aliasing, use:
# mmm_audio = MMMAudio(128, graph_name="BuchlaWaveFolder", package_name="examples")
mmm_audio.start_audio() 

mmm_audio.stop_audio()
mmm_audio.plot(4000)

# plot the spectrum of the the plotted output
from numpy import fft
from matplotlib import pyplot as plt
spectrum = fft.rfft(mmm_audio.returned_samples[:, 0])
plt.plot(spectrum)
plt.show()

Mojo Code

from mmm_audio import *

struct BuchlaWaveFolder(Representable, Movable, Copyable):
    var world: UnsafePointer[MMMWorld]  
    var osc: Osc[2]
    var lag: Lag
    var m: Messenger


    fn __init__(out self, world: UnsafePointer[MMMWorld]):
        self.world = world
        # for efficiency we set the interpolation and oversampling in the constructor
        self.osc = Osc[2](self.world)
        self.lag = Lag(self.world, 0.1)
        self.m = Messenger(self.world)

    fn __repr__(self) -> String:
        return String("Default")

    fn next(mut self) -> SIMD[DType.float64, 2]:
        amp = self.lag.next(self.world[].mouse_x * 39.0) + 1

        sample = self.osc.next_vwt(40)
        sample = buchla_wavefolder(sample, amp)

        return sample