Java tutorial
import javax.sound.midi.MidiChannel; import javax.sound.midi.MidiSystem; import javax.sound.midi.Sequencer; import javax.sound.midi.Synthesizer; public class Main { public static void main(String[] argv) throws Exception { Sequencer sequencer = MidiSystem.getSequencer(); sequencer.open(); if (sequencer instanceof Synthesizer) { Synthesizer synthesizer = (Synthesizer) sequencer; MidiChannel[] channels = synthesizer.getChannels(); // gain is a value between 0 and 1 (loudest) double gain = 0.9D; for (int i = 0; i < channels.length; i++) { channels[i].controlChange(7, (int) (gain * 127.0)); } } } }