Controlling the Volume of Playing Midi Audio 
To create a Sequencer object, see ``Loading and Playing Midi Audio'' and ``Playing Streaming Midi Audio''. 

 
 if (sequencer instanceof Synthesizer) {
   Synthesizer synthesizer = (Synthesizer)sequencer;
   MidiChannel[] channels = synthesizer.getChannels();
         
   // gain is a value between 0 and 1.
   for (int i=0; i<channels.length; i++) {                
     channels[i].controlChange(7, (int)(gain * 127.0));
   }
 }