What software could I use to create a WAV file from a function of sample number?
I am building an implementation of Group Additive Synthesis in a modular softsynth and I just need a simple way of creating the wavetables.
If simple waveforms are enough, Audacity is a (free and) convenient tool to go for. In the version I use (2.1.2), the following are creatable per default (please see below for plugin add-on):
Simple waveforms (you can specify frequency, amplitude and duration):
Chirps (amplitude and frequency changes over time (additionally, interpolation curve is selectable here ("linear" vs. "logarithmic"))
Noise (you can specify amplitude and duration):
Simple risset drums (editable frequency, decay, center frequency of noise, width of noise band, amount of moise in mix, amplitude).
Simple pluck strings (editable duration, fade out type and midi note height).
Furthermore, there are plugins that might be of interest in your case. See this one for example.
You can export your generated waveform in many audio formats, including several
.wav formats with different bit depth.