JMSL Tutorial: Instruments and Interpreters

You may worry that JMSL's Instrument and Interpreter approach is so open ended that you have to build everything from scratch. Not so. For example, JMSL already includes MidiInstrument than excels at sending Midi notes out to your favorite Midi device. The best API for doing this is Grame's MidiShare, since it supports time-stamped MIDI output at the note level. Since MidiShare uses a native library, we cannot demonstrate MidiShare in these Applets.

Instead, here we will send MIDI using JMSL's MidiIO_JavaSound MusicDevice. Sun's JavaSound MIDI package provides MIDI output, does not support MIDI input, and at this time, does not support timestamped output, so timing will be no more accurate than Java Thread scheduling (fast tight melodies will probably sound ragged). The melody played here is a little more "floating" so the timing issue is not so apparent.
You need a Java enabled Web Browser to view this applet
Applet Source
A few words on MidiInstrument...

MidiInstrument is an Instrument subclass that uses a standard MidiInterpreter to play Midi note data stored in a MusicShape.

MusicShape data that plays a staccato chromatic melody would look like this, for example:
dur  pitch  vel   sustain
1.0 65.0 120.0 0.25
1.0 66.0 120.0 0.25
1.0 67.0 120.0 0.25
1.0 68.0 120.0 0.25

Overlapping pitches could be achieved like this:
dur  pitch  vel   sustain
1.0 65.0 120.0 1.5
1.0 66.0 120.0 1.5
1.0 67.0 120.0 1.5
1.0 68.0 120.0 1.5

A big fat 4-note chord held for 10 seconds would look like this:
dur  pitch  vel   sustain
0.0 65.0 120.0 10.0
0.0 66.0 120.0 10.0
0.0 67.0 120.0 10.0
1.0 68.0 120.0 10.0

Any MusicShape that conforms to this dimension definition can setInstrument(new MidiInstrument()) and send Midi notes.

Of course, you can create data on-the-fly instead of first building a MusicShape. Use MidiInstrument's noteOnFor() method to do this. For example, the following line of code could be put into a repeat() method of a MusiciJob which had a MidiInstrument.
// Bang a Midi note using noteOnFor(double playTime, double timeStretch, int pitch, int vel, double holdtime)

((MidiInstrument)getInstrument()).noteOnFor(playTime, 1.0, JMSLRandom.choose(50,74), JMSLRandom.choose(40,128), 0.5 + JMSLRandom.choose(3.0));

Next, we will see how to create a custom Instrument that plays a simple JSyn circuit. You will need the JSyn plug-in, available at

Previous Tutorial Index Tutorial Contents Next
  (C) 1997 Phil Burk and Nick Didkovsky, All Rights Reserved
JMSL is based upon HMSL (C) Phil Burk, Larry Polansky and David Rosenboom.