this is a test / proof of concept for integrating external audio-processing engines with a norns script.
please note that this was authored very quickly, includes FIXMEs and likely bugs; PRs are welcome to improve its utility as an example.
the "engine" in this case is a standalone JACK client and OSC server:
-
engine source is included here under
ignore/ztsingou-engine, and is a standard CMake project. -
an executable binary built on rpi4 is included in
ignore/ztsingou-engine/bin-rpi. -
the executable is launched, ports assigned, and JACK connections made in the script
lib/run-norns.sh -
lua API for the engine is defined in
lib/ztsingou-engine.lua. notably, it requires a callback to wait for the engine to be initialized.
the engine is a dual physical model of a string with nonlinear force characteristics. each string can be "plucked" or excited with external audio.
per-string parameters:
-- output amplitude
'amp',
-- pickup and excitation positions (2-15)
'pickupPos1', 'pickupPos2', 'excitePos',
-- tension coefficient
'beta',
-- nonlinear stiffness coefficient
'epsilon',
-- damping
'rho',
-- stateless parameter; sets the position of the mass at the excitation point
'pluck'
global paramaeters:
-- amount of stereo spread between each pickup point on each string
-- first pickup on each string is always panned hard left/right
'spread',
-- increase to "mono-ize" the final output mix
'mono',
-- input gain for excitation
-- applies to both channels; each input channel goes to a different string
'gain',
-- iterations per sample. this is rounded to an integer.
-- increasing IPS multiplies both pitch and CPU
'ips',
-- number of masses to compute per string
-- changes the distribution of resonant modes,
-- increases / decreases CPU load
'masses'