[java] MIDI volume change problem

Hello, I have been having a problem with changing MIDI volume. What happens is that when a software synthesizer is used, I can send a volume control change message of zero, but volume does not become completely silent. If a hardware synthesizer is used, the volume change works properly. Here are the relevant parts of my code for reference: Set up the MIDI sequence, sequencer, and synthesizer:

    private static final int CHANGE_VOLUME = 7;

    private Sequencer sequencer = null;
    private Synthesizer synthesizer = null;
    private Sequence sequence = null;

...

        URL midiSource = getClass().getClassLoader().getResource( filename );
        if( midiSource == null )
        {
            System.err.println( "Unable to load Midi file." );
            return;
        }

        try
        {
            sequence = MidiSystem.getSequence( midiSource );
            sequencer = MidiSystem.getSequencer();
            sequencer.open();
            sequencer.setSequence( sequence );
        }
        catch( IOException ioe )
        {
            System.err.println( "Failed to read from MIDI file." );
            return;
        }
        catch( InvalidMidiDataException imde )
        {
            System.err.println( "Invalid MIDI data encountered." );
            return;
        }
        catch( MidiUnavailableException mue )
        {
            System.err.println( "MIDI unavailable." );
            return;
        }
        catch( Exception e )
        {
            System.err.println( "Unexpected problem loading MIDI file." );
            return;
        }

        try
        {
            synthesizer = MidiSystem.getSynthesizer();
            synthesizer.open();
            if( synthesizer.getDefaultSoundbank() == null )
            {
                // HARDWARE SYNTHESIZER
                sequencer.getTransmitter().setReceiver(
                    MidiSystem.getReceiver() );
            }
            else
            {
                // SOFTWARE SYNTHESIZER
                sequencer.getTransmitter().setReceiver(
                    synthesizer.getReceiver() );
            }
        }
        catch( MidiUnavailableException mue )
        {
            errorMessage( "MIDI unavailable." );
            return;
        }
        catch( Exception e )
        {
            errorMessage( "Unexpected problem linking to synthesizer " );
            return;
        }

Then, to change the volume:

            // NOTE: variable 'midiVolume' is an int between 0 and 127
            if( synthesizer.getDefaultSoundbank() == null )
            {
                // HARDWARE SYNTHESIZER
                try
                {
                    ShortMessage volumeMessage = new ShortMessage();
                    for( int i = 0; i < 16; i++ )
                    {
                        volumeMessage.setMessage( ShortMessage.CONTROL_CHANGE,
                            i, CHANGE_VOLUME, midiVolume );
                        MidiSystem.getReceiver().send( volumeMessage, -1 );
                    }
                }
                catch( InvalidMidiDataException imde )
                {
                    System.err.println( "Invalid MIDI data." );
                    return;
                }
                catch( MidiUnavailableException mue )
                {
                    System.err.println( "MIDI unavailable." );
                    return;
                }
            }
            else
            {
                // SOFTWARE SYNTHESIZER:
                MidiChannel[] channels = synthesizer.getChannels();
                for( int c = 0; channels != null && c < channels.length; c++ )
                {
                    channels[c].controlChange( CHANGE_VOLUME, midiVolume );
                }
            }

I have also tried using this instead for software-synthesis mode, but it has the same effect (i.e. volume is not silent at midiVolume=0):

                ShortMessage volumeMessage = new ShortMessage();
                for( int i = 0; i < 16; i++ )
                {
                    volumeMessage.setMessage( ShortMessage.CONTROL_CHANGE, i,
                                              CHANGE_VOLUME, midiVolume );
                    synthesizer.getReceiver().send( volumeMessage, -1 );
                }

For reference, here is a link to a test applet: http://www.paulscode.com/source/MIDI/MIDIApplet/ If your output says "getDefaultSoundbank() did NOT return null", that means you are using a software synthesizer, and the volume will not become silent at zero. On the other hand, if your output says "getDefaultSoundbank() returned null", it means you are using a hardware synthesizer, and the volume change will work correctly. Does anyone have any ideas how to correct this problem? Thanks in advance!