Re: [fluid-dev] IIR low pass filter

[Tom M.]

Every SF2 compliant synthesizer has a low pass filter in place. To use
that, open a SF2 editor, select an instrument and specify filter
cutoff frequency and filter Q.

To automate this via MIDI events, you should learn about Soundfont
modulators, and how they influence the values that you have entered in
the previous step. Then, by using the SF2 editor, set up a modulator
for that / those instrument(s) that you would like to control.

To avoid copy&pasting the same modulators to all instruments and all
soundfonts, you can use fluid_synth_add_default_mod() to set up a
default modulator. This is fluidsynth-specific and not portable to
other SF2 synths, though.

Alternatively, you can use MIDI NRPNs to manipulate the filter cutoff
freq. and Q.

fluid_synth_set_custom_filter() is intended for advanced use-cases and
most likely not what you want or need.

An int is an integer, refer to
https://en.wikipedia.org/wiki/Integer_(computer_science)

Tom