Looks like your code is good. I tried my own Midi class (which basically has the same code as yours) and it seemed to work…strange. Take a look at this modified code:

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;

import javax.sound.midi.*;

public class MidiSynthesizerSample {
	public static void main(String[] args) {
		// get all the default stuff
		try {
			Sequence sequence = MidiSystem.getSequence(new File("c:/bass_1.mid"));
			Sequencer sequencer = MidiSystem.getSequencer(false);
			Receiver receiver = MidiSystem.getReceiver();
			// open the sequencer and wire up the receiver
			// and transmitter

			sequencer.open();
			sequencer.getTransmitter().setReceiver(receiver);
			// play the MIDI
			sequencer.setSequence(sequence);
			sequencer.start();

			try {
				Thread.sleep(1000);
			} catch (InterruptedException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}

			setVolume(20);

			try {
				Thread.sleep(5000);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

			sequencer.close();
			receiver.close();

		} catch (MalformedURLException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (InvalidMidiDataException e) {
			e.printStackTrace();
		} catch (MidiUnavailableException e) {
			e.printStackTrace();
		}
	}

	public static void setVolume(int value) {
		try {
			ShortMessage volumeMessage = new ShortMessage();
			for (int i = 0; i < 16; i++) {
				volumeMessage.setMessage(ShortMessage.CONTROL_CHANGE, i, 7, value);
				MidiSystem.getReceiver().send(volumeMessage, -1);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

It works for me. It seems that you have to give the sequencer time to open before actually setting the volume in the case that Java uses the hardware synthesizer (I have it pausing for 1 second here but I tried 10 milliseconds and that seemed to work as well). I tested with a couple of midi’s that I had and it reminded me of another problem you might run into: midi files can contain the volume control messages! So make sure you midi is an midi that the volume can be changed on.

One more thing. If you are deploying a real app that uses Midi, I would recommend just packaging a soundbank with your application and load it up like:

synthesizer = MidiSystem.getSynthesizer();
synthesizer.loadAllInstruments(MidiSystem.getSoundbank(inputStream));

This will allow you to use the default synthesizer instead of using the finicky hardware one.

1. Try your code on this midi file and see if it works. Unfortunately I’m not familiar with any methods to modify or inspect midi files so I can’t help you find out if the file you are using is the problem or not. The linked midi file is the one I tested with and it seems to work.

2. If you want to use the default synthesizer you must go out and download a soundbank from . Then you basically do everything the same:

// the sound bank file
File soundbank = new File("c:/soundbank.gm");
// the midi file
File sequence = new File("c:/1.mid");
// get the sequencer
Sequencer sequencer = MidiSystem.getSequencer(false);
// get the synthesizer
Synthesizer synthesizer = MidiSystem.getSynthesizer();
// load up the instruments into the synthesizer
synthesizer.loadAllInstruments(MidiSystem.getSoundbank(soundbank));
// open the synthesizer
synthesizer.open();
// get the synthesizer's receiver
Receiver receiver = synthesizer.getReceiver();
// open the sequencer
sequencer.open();
// wire up the two
sequencer.getTransmitter().setReceiver(receiver);
// set the midi file to play
sequencer.setSequence(sequence);
// start the playback
sequencer.start();
// set the volume the normal way
setVolume(10);

public static void setVolume(int volume, Synthesizer synthesizer) {
  MidiChannel[] channels = synthesizer.getChannels();
  // set the master volume for each channel
  for (int i = 0; i < channels.length; i++) {
    channels[i].controlChange(7, volume);
  }
}

You can also take a look at my implementation which seems to work for me here. Feel free to copy and modify. You use it like the following:

// create a new midi object
// NOTE: the file must be on the classpath
Midi midi = new Midi("/1.mid");
midi.open();
midi.play();
midi.setVolume(10);
// then when you want to stop it
midi.stop();
// dont forget to close it when you app closes
midi.close();

Awesome, I glad to hear that, no pun intended. Yes, as you point out a busy wait will probably not work, however a Thread.sleep(10) will (at least did for me).

If you didn’t want to do this then you may be able to listen for a “start” event, then set the volume. I have not done this myself you but if you want, you can check out how to listen for events . You can listen for either Meta events or control events.

If it exists, a start event would be a Meta event. If you look at my code you’ll see that I already listen for a “track end” event. It should be very similar to this. Once you receive the event, set the volume. I’m not sure what the event number is but you can reference to try to figure it out.

As far as my code is concerned, it seems like I must be doing enough before setting the volume so that I don’t have this problem. However, I have noticed that this problem will crop up from time to time.

Hope this helps