Strudel's audio engine is SuperDough (2023) mostly by @froos, which is based on SuperDirt (2015) mostly by @juliantelephon, which is based on 'dirt' a sampler made by me and originally called 'datadirt' (2005), but very heavily based on MSG (2001) by @adeward

Some of MSG's features got lost in translation, like line hum (configurable 50Hz or 60Hz) and hiss, and a weird synth controlled by a four-character string, here's the docs for that:

>make [name] from [synthcode] speed [rate]
Creates a new (or, if it already exists, modifies an existing) synth
using the four-digit synthcode. The first digit defines the waveform:
s for sine, t for triangle, q for square and r for random. The next
three digits range from 0.0 (a) to 1.0 (z) and define, respectively, the
pulse width, pulse amplitude, and waveform decay. Thus, using only
four letters, any number of FM-like synthesis sounds can be generated.
Here are a few examples:
'qaaa' - solid square
'qaaz' - sharp pulse (square with maximum decay)
'qmmz' - sharp pulse with 50% resonant pulse
'tilt' - triangular with sharpish edge synth
'slub' - smoothish sinusoidal waveform

* MSG: https://cors.slab.org/MSG-1.10.tar.gz
* datadirt: https://cors.slab.org/datadirt_1.0.0.tar.gz
* dirt: https://codeberg.org/uzu/dirt
* superdirt: https://github.com/musikinformatik/SuperDirt
* superdough: https://codeberg.org/uzu/strudel/src/branch/main/packages/superdough