Basics of creating wavetables in Octave Vol.1

4/28/2021

Learn how to use Octave to create Wavetables.

I will show you how to create a Wavetable in Octave, a numerical calculation software. The waveforms you create can be used with Serum, Ableton Wavetable, or any other audio-importable wavetable synth or sampler.

GNU Octave

https://www.gnu.org/software/octave/index

Octave Programiming Tutorial

Advice

Octave is compatible with Matlab, so if there is a function you are not sure about, the Matlab web page is also a good reference.
In Octave, if you don't put " ;" at the end of a line, the result of the calculation will be output to the command window. When looping, if you do not put a " ;" at the end of a line, the result of the calculation will be output to the command window endlessly, so be careful.

Generating a sine wave

First, generate a single-cycle sine wave. The format is a 44.1kHz -16bit-Wav file with 2048 samples in length.
Create a linearly aligned vector with the linspace function to generate a sine wave. Outputs 2049 equally spaced points in the range 0 to 2π.

Download

audiowrite should be typed in order of file name, output waveform, sampling frequency, and bits. The bit values can be changed to 8, 16 or 32.

Changing the volume

To change the volume, multiply the waveform.　Volume, from one to zero.

Changing the interval

The interval can be changed by multiplying by an integer.

Changing the phase

Adding pi/2 shifts it 25% from the original waveform; adding pi shifts it 50% and reverses it from the original waveform; adding 3/2*pi shifts it 75%; adding 2*pi shifts it 100% and returns it to the original waveform.