LibBitDauer v0.1

A simple software synthesizer package for my audio projects. Also includes some basic sound analysis tools for no reason.

Limitations:

• It has some limited support for continuous generation, but currently it is only used to generate into a fixed size buffer.
• The envelope is also supposed to fully support the MIDI key-trigger mechanics, but it's never been used.

Features

• Oscillator
  • Wave functions:
    • Sine, square, triangle, sawtooth, reverse sawtooth
    • Noise:
      • White (using built-in Go rand.Rand)
      • Red, pink, blue, violet (by applying filters to the white noise)
• Modulators:
  • Envelope (ADSR with various shapes):
    • LERP
    • Ease-in, ease-out, ease-in-out
    • Exponential, logarithmic, inverse exponential, inverse logarithmic
    • S-Curve (sigmoid)
  • LFO (can use all wave functions above)
• Filters:
  • Single, chain, chain of chain
  • Low-pass, high-pass, band-pass, notch, peaking
• Musical scale LUT generator based on a base note frequency
• Output options:
  • Export to WAV or raw (unsigned 32 bit integer) format
  • Play as 1 channel 44.1kHz using the oto package

Examples

Some examples are provided in the cmd folder, both for the synth and the analysis tools.

Genex

The synth example creates an oscillator that outputs an A4 note with a customized envelope into a 2-second-long buffer. The generated sound will be played with the default sound device and saved as a WAV file.

Idex

Loads a WAV file and extracts the dominant frequencies to identify the waveform. It also saves the extracted data into a CSV, and generates various diagrams into PNGs. An example untuned identification is performed using the harmonic ratios and another with other metrics (bandwidth, spectral centroid).

TODOs

A rough list of planned features:

• Mixer to have multiple oscillators
• PWM generator
• Filter support to the oscillator
• Free form modulator (multiple envelope sections with selectable easing functions)
• Other filters like expander, compressor, limiter
• Handle overdrive

License

This project is licensed under the MIT License. See the LICENSE file for details.