"output volume is too small"

[atsushieno]

By default fluidsynth output volume is quite low, because it is possible for synthesizers like fluidsynth to process so many notes that it could result in output saturation.

It is controlled by "synth.gain" settings item, which is 0.2 by default, while it can be raised up to 1.0.

http://www.fluidsynth.org/api/fluidsettings.xml#synth.gain

If you're using fluidsynthjna, then code like settings.getEntry (ConfigurationKeys.SynthGain).setDoubleValue (0.5) (Kotlin) should work.

It is left open so that people can easily find the FAQ.