FluidSynth version

2.5.0

Describe the bug

When FluidSynth receives a pitch bend sensitivity event after a non-zero-value master fine tuning event, the channel's pitch bends are noticeably off. They're either too sharp or too flat compared to if the channel's fine tuning is set to 0. The bug is more severe the further away from zero the master fine tuning value is set to.

Expected behavior

The pitch bends sound correct, as demonstrated in the MSGS recording provided in the ZIP below.

Steps to reproduce

1. Run fluidsynth with the soundfont of your choice and the provided MIDI.
2. Listen to the MIDI's off-pitch pitch bends.

Additional context

I have provided a MIDI for testing purposes, as well as two recordings of it: One uses the Microsoft GS Wavetable Synth, while the other uses FluidSynth with gm.dls loaded as the soundfont.

FluidSynth pitch bend fine tuning bug demonstration.zip