Merge pull request #41 from philburk/instruments

Instruments

36 files changed, 1356 insertions, 211 deletions

diff --git a/src/com/jsyn/apps/InstrumentTester.java b/src/com/jsyn/apps/InstrumentTester.java
index 4186703..6e347cd 100644
--- a/src/com/jsyn/apps/InstrumentTester.java
+++ b/src/com/jsyn/apps/InstrumentTester.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -17,12 +17,19 @@
 package com.jsyn.apps;
 
 import java.awt.BorderLayout;
+import java.io.IOException;
 
+import javax.sound.midi.MidiDevice;
+import javax.sound.midi.MidiMessage;
+import javax.sound.midi.MidiUnavailableException;
+import javax.sound.midi.Receiver;
 import javax.swing.JApplet;
 
 import com.jsyn.JSyn;
 import com.jsyn.Synthesizer;
+import com.jsyn.devices.javasound.MidiDeviceTools;
 import com.jsyn.instruments.JSynInstrumentLibrary;
+import com.jsyn.midi.MessageParser;
 import com.jsyn.swing.InstrumentBrowser;
 import com.jsyn.swing.JAppletFrame;
 import com.jsyn.swing.PresetSelectionListener;
@@ -32,11 +39,14 @@ import com.jsyn.unitgen.UnitSource;
 import com.jsyn.unitgen.UnitVoice;
 import com.jsyn.util.PolyphonicInstrument;
 import com.jsyn.util.VoiceDescription;
+import com.softsynth.math.AudioMath;
+import com.softsynth.shared.time.TimeStamp;
 
 /**
- * Let the user select an instrument using the InstrumentBrowser and play them using the ASCII
- * keyboard. Sound parameters can be tweaked using faders.
- * 
+ * Let the user select an instrument using the InstrumentBrowser and play
+ * them using the ASCII keyboard or with MIDI.
+ * Sound parameters can be tweaked using faders.
+ *
  * @author Phil Burk (C) 2012 Mobileer Inc
  */
 public class InstrumentTester extends JApplet {
@@ -44,6 +54,64 @@ public class InstrumentTester extends JApplet {
     private Synthesizer synth;
     private LineOut lineOut;
     private SoundTweaker tweaker;
+    protected PolyphonicInstrument instrument;
+    private MyParser messageParser;
+
+    class MyParser extends MessageParser {
+
+        @Override
+        public void controlChange(int channel, int index, int value) {
+        }
+
+        @Override
+        public void noteOff(int channel, int noteNumber, int velocity) {
+            instrument.noteOff(noteNumber, synth.createTimeStamp());
+        }
+
+        @Override
+        public void noteOn(int channel, int noteNumber, int velocity) {
+            double frequency = AudioMath.pitchToFrequency(noteNumber);
+            double amplitude = velocity / (4 * 128.0);
+            TimeStamp timeStamp = synth.createTimeStamp();
+            instrument.noteOn(noteNumber, frequency, amplitude, timeStamp);
+        }
+
+    }
+
+    // Write a Receiver to get the messages from a Transmitter.
+    class CustomReceiver implements Receiver {
+        @Override
+        public void close() {
+            System.out.print("Closed.");
+        }
+
+        @Override
+        public void send(MidiMessage message, long timeStamp) {
+            byte[] bytes = message.getMessage();
+            messageParser.parse(bytes);
+        }
+    }
+
+    public int setupMidiKeyboard() throws MidiUnavailableException, IOException, InterruptedException {
+        messageParser = new MyParser();
+
+        int result = 2;
+        MidiDevice keyboard = MidiDeviceTools.findKeyboard();
+        Receiver receiver = new CustomReceiver();
+        // Just use default synthesizer.
+        if (keyboard != null) {
+            // If you forget to open them you will hear no sound.
+            keyboard.open();
+            // Put the receiver in the transmitter.
+            // This gives fairly low latency playing.
+            keyboard.getTransmitter().setReceiver(receiver);
+            System.out.println("Play MIDI keyboard: " + keyboard.getDeviceInfo().getDescription());
+            result = 0;
+        } else {
+            System.out.println("Could not find a keyboard.");
+        }
+        return result;
+    }
 
     @Override
     public void init() {
@@ -61,7 +129,7 @@ public class InstrumentTester extends JApplet {
                 for (int i = 0; i < voices.length; i++) {
                     voices[i] = voiceDescription.createUnitVoice();
                 }
-                PolyphonicInstrument instrument = new PolyphonicInstrument(voices);
+                instrument = new PolyphonicInstrument(voices);
                 synth.add(instrument);
                 instrument.usePreset(presetIndex, synth.createTimeStamp());
                 String title = voiceDescription.getVoiceClassName() + ": "
@@ -71,6 +139,19 @@ public class InstrumentTester extends JApplet {
         });
         add(browser, BorderLayout.NORTH);
 
+        try {
+            setupMidiKeyboard();
+        } catch (MidiUnavailableException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        } catch (IOException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        } catch (InterruptedException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+
         validate();
     }
 
diff --git a/src/com/jsyn/engine/MultiTable.java b/src/com/jsyn/engine/MultiTable.java
index 48b03cd..6606639 100644
--- a/src/com/jsyn/engine/MultiTable.java
+++ b/src/com/jsyn/engine/MultiTable.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -20,7 +20,7 @@ package com.jsyn.engine;
  * Multiple tables of sawtooth data.
  * organized by octaves below the Nyquist Rate.
  * used to generate band-limited Sawtooth, Impulse, Pulse, Square and Triangle BL waveforms
- * 
+ *
  <pre>
  Analysis of octave requirements for tables.
 
diff --git a/src/com/jsyn/engine/SynthesisEngine.java b/src/com/jsyn/engine/SynthesisEngine.java
index e966b30..ae16405 100644
--- a/src/com/jsyn/engine/SynthesisEngine.java
+++ b/src/com/jsyn/engine/SynthesisEngine.java
@@ -222,13 +222,6 @@ public class SynthesisEngine implements Synthesizer {
         this.frameRate = frameRate;
         this.framePeriod = 1.0 / frameRate;
 
-        // Set rate for any units that have already been added.
-        for (UnitGenerator ugen : allUnitList) {
-            ugen.setFrameRate(frameRate);
-        }
-
-        // this.numInputChannels = numInputChannels;
-        // this.numOutputChannels = numOutputChannels;
         setupAudioBuffers(numInputChannels, numOutputChannels);
 
         logger.info("Pure Java JSyn from www.softsynth.com, rate = " + frameRate + ", "
@@ -652,9 +645,6 @@ public class SynthesisEngine implements Synthesizer {
     public void add(UnitGenerator ugen) {
         ugen.setSynthesisEngine(this);
         allUnitList.add(ugen);
-        if (frameRate > 0) {
-            ugen.setFrameRate(frameRate);
-        }
     }
 
     @Override
diff --git a/src/com/jsyn/instruments/DualOscillatorSynthVoice.java b/src/com/jsyn/instruments/DualOscillatorSynthVoice.java
new file mode 100644
index 0000000..c81041f
--- /dev/null
+++ b/src/com/jsyn/instruments/DualOscillatorSynthVoice.java
@@ -0,0 +1,301 @@
+/*
+ * Copyright 2010 Phil Burk, Mobileer Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jsyn.instruments;
+
+import com.jsyn.ports.UnitInputPort;
+import com.jsyn.ports.UnitOutputPort;
+import com.jsyn.unitgen.Add;
+import com.jsyn.unitgen.Circuit;
+import com.jsyn.unitgen.EnvelopeDAHDSR;
+import com.jsyn.unitgen.FilterFourPoles;
+import com.jsyn.unitgen.MorphingOscillatorBL;
+import com.jsyn.unitgen.Multiply;
+import com.jsyn.unitgen.UnitVoice;
+import com.jsyn.util.VoiceDescription;
+import com.softsynth.math.AudioMath;
+import com.softsynth.shared.time.TimeStamp;
+
+/**
+ * Synthesizer voice with two morphing oscillators and a four-pole resonant filter.
+ * Modulate the amplitude and filter using DAHDSR envelopes.
+ */
+public class DualOscillatorSynthVoice extends Circuit implements UnitVoice {
+    private Multiply frequencyMultiplier;
+    private Multiply amplitudeMultiplier;
+    private Multiply detuneScaler1;
+    private Multiply detuneScaler2;
+    private Multiply amplitudeBoost;
+    private MorphingOscillatorBL osc1;
+    private MorphingOscillatorBL osc2;
+    private FilterFourPoles filter;
+    private EnvelopeDAHDSR ampEnv;
+    private EnvelopeDAHDSR filterEnv;
+    private Add cutoffAdder;
+
+    private static MyVoiceDescription voiceDescription;
+
+    public UnitInputPort amplitude;
+    public UnitInputPort frequency;
+    /**
+     * This scales the frequency value. You can use this to modulate a group of instruments using a
+     * shared LFO and they will stay in tune. Set to 1.0 for no modulation.
+     */
+    public UnitInputPort frequencyScaler;
+    public UnitInputPort oscShape1;
+    public UnitInputPort oscShape2;
+//    public UnitInputPort oscDetune1;
+//    public UnitInputPort oscDetune2;
+    public UnitInputPort cutoff;
+    public UnitInputPort filterEnvDepth;
+    public UnitInputPort Q;
+
+    public DualOscillatorSynthVoice() {
+        add(frequencyMultiplier = new Multiply());
+        add(amplitudeMultiplier = new Multiply());
+        add(amplitudeBoost = new Multiply());
+        add(detuneScaler1 = new Multiply());
+        add(detuneScaler2 = new Multiply());
+        // Add tone generators.
+        add(osc1 = new MorphingOscillatorBL());
+        add(osc2 = new MorphingOscillatorBL());
+
+        // Use an envelope to control the amplitude.
+        add(ampEnv = new EnvelopeDAHDSR());
+
+        // Use an envelope to control the filter cutoff.
+        add(filterEnv = new EnvelopeDAHDSR());
+        add(filter = new FilterFourPoles());
+        add(cutoffAdder = new Add());
+
+        filterEnv.output.connect(cutoffAdder.inputA);
+        cutoffAdder.output.connect(filter.frequency);
+        frequencyMultiplier.output.connect(detuneScaler1.inputA);
+        frequencyMultiplier.output.connect(detuneScaler2.inputA);
+        detuneScaler1.output.connect(osc1.frequency);
+        detuneScaler2.output.connect(osc2.frequency);
+        osc1.output.connect(amplitudeMultiplier.inputA); // mix oscillators
+        osc2.output.connect(amplitudeMultiplier.inputA);
+        amplitudeMultiplier.output.connect(filter.input);
+        filter.output.connect(amplitudeBoost.inputA);
+        amplitudeBoost.output.connect(ampEnv.amplitude);
+
+        addPort(amplitude = amplitudeMultiplier.inputB, PORT_NAME_AMPLITUDE);
+        addPort(frequency = frequencyMultiplier.inputA, PORT_NAME_FREQUENCY);
+        addPort(oscShape1 = osc1.shape, "OscShape1");
+        addPort(oscShape2 = osc2.shape, "OscShape2");
+//        addPort(oscDetune1 = osc1.shape, "OscDetune1");
+//        addPort(oscDetune2 = osc2.shape, "OscDetune2");
+        addPort(cutoff = cutoffAdder.inputB, PORT_NAME_CUTOFF);
+        addPortAlias(cutoff, PORT_NAME_TIMBRE);
+        addPort(Q = filter.Q);
+        addPort(frequencyScaler = frequencyMultiplier.inputB, PORT_NAME_FREQUENCY_SCALER);
+        addPort(filterEnvDepth = filterEnv.amplitude, "FilterEnvDepth");
+
+        filterEnv.export(this, "Filter");
+        ampEnv.export(this, "Amp");
+
+        frequency.setup(osc1.frequency);
+        frequencyScaler.setup(0.2, 1.0, 4.0);
+        cutoff.setup(filter.frequency);
+        // Allow negative filter sweeps
+        filterEnvDepth.setup(-4000.0, 2000.0, 4000.0);
+
+        // set amplitudes slightly different so that they never entirely cancel
+        osc1.amplitude.set(0.5);
+        osc2.amplitude.set(0.4);
+        // Make the circuit turn off when the envelope finishes to reduce CPU load.
+        ampEnv.setupAutoDisable(this);
+        // Add named port for mapping pressure.
+        amplitudeBoost.inputB.setup(1.0, 1.0, 4.0);
+        addPortAlias(amplitudeBoost.inputB, PORT_NAME_PRESSURE);
+
+        usePreset(0);
+    }
+
+    /**
+     * The first oscillator will be tuned UP by semitoneOffset/2.
+     * The second oscillator will be tuned DOWN by semitoneOffset/2.
+     * @param semitoneOffset
+     */
+    private void setDetunePitch(double semitoneOffset) {
+        double halfOffset = semitoneOffset * 0.5;
+        setDetunePitch1(halfOffset);
+        setDetunePitch2(-halfOffset);
+    }
+
+    /**
+     * Set the detuning for osc1 in semitones.
+     * @param semitoneOffset
+     */
+    private void setDetunePitch1(double semitoneOffset) {
+        double scale = AudioMath.semitonesToFrequencyScaler(semitoneOffset);
+        detuneScaler1.inputB.set(scale);
+    }
+
+    /**
+     * Set the detuning for osc2 in semitones.
+     * @param semitoneOffset
+     */
+    private void setDetunePitch2(double semitoneOffset) {
+        double scale = AudioMath.semitonesToFrequencyScaler(semitoneOffset);
+        detuneScaler2.inputB.set(scale);
+    }
+
+    @Override
+    public void noteOff(TimeStamp timeStamp) {
+        ampEnv.input.off(timeStamp);
+        filterEnv.input.off(timeStamp);
+    }
+
+    @Override
+    public void noteOn(double freq, double ampl, TimeStamp timeStamp) {
+        frequency.set(freq, timeStamp);
+        amplitude.set(ampl, timeStamp);
+        ampEnv.input.on(timeStamp);
+        filterEnv.input.on(timeStamp);
+    }
+
+    @Override
+    public UnitOutputPort getOutput() {
+        return ampEnv.output;
+    }
+
+    // Reset to basic voice.
+    public void reset() {
+        osc1.shape.set(0.0);
+        osc2.shape.set(0.0);
+        ampEnv.attack.set(0.005);
+        ampEnv.decay.set(0.2);
+        ampEnv.sustain.set(0.5);
+        ampEnv.release.set(1.0);
+        filterEnv.attack.set(0.01);
+        filterEnv.decay.set(0.6);
+        filterEnv.sustain.set(0.4);
+        filterEnv.release.set(1.0);
+        cutoff.set(500.0);
+        filterEnvDepth.set(3000.0);
+        filter.reset();
+        filter.Q.set(3.9);
+        setDetunePitch(0.02);
+    }
+
+    @Override
+    public void usePreset(int presetIndex) {
+        reset(); // start from known configuration
+        int n = presetIndex % presetNames.length;
+        switch (n) {
+            case 0:
+                break;
+            case 1:
+                ampEnv.attack.set(0.1);
+                ampEnv.decay.set(0.9);
+                ampEnv.sustain.set(0.1);
+                ampEnv.release.set(0.1);
+                cutoff.set(500.0);
+                filterEnvDepth.set(500.0);
+                filter.Q.set(3.0);
+                break;
+            case 2:
+                ampEnv.attack.set(0.1);
+                ampEnv.decay.set(0.3);
+                ampEnv.release.set(0.5);
+                cutoff.set(2000.0);
+                filterEnvDepth.set(500.0);
+                filter.Q.set(2.0);
+                break;
+            case 3:
+                osc1.shape.set(-0.9);
+                osc2.shape.set(-0.8);
+                ampEnv.attack.set(0.3);
+                ampEnv.decay.set(0.8);
+                ampEnv.release.set(0.2);
+                filterEnv.sustain.set(0.7);
+                cutoff.set(500.0);
+                filterEnvDepth.set(500.0);
+                filter.Q.set(3.0);
+                break;
+            case 4:
+                osc1.shape.set(1.0);
+                osc2.shape.set(0.0);
+                break;
+            case 5:
+                osc1.shape.set(1.0);
+                setDetunePitch1(0.0);
+                osc2.shape.set(0.9);
+                setDetunePitch1(7.0);
+                break;
+            case 6:
+                osc1.shape.set(0.6);
+                osc2.shape.set(-0.2);
+                setDetunePitch1(0.01);
+                ampEnv.attack.set(0.005);
+                ampEnv.decay.set(0.09);
+                ampEnv.sustain.set(0.0);
+                ampEnv.release.set(1.0);
+                filterEnv.attack.set(0.005);
+                filterEnv.decay.set(0.1);
+                filterEnv.sustain.set(0.4);
+                filterEnv.release.set(1.0);
+                cutoff.set(2000.0);
+                filterEnvDepth.set(5000.0);
+                filter.Q.set(7.02);
+                break;
+            default:
+                break;
+        }
+    }
+
+    private static final String[] presetNames = {
+            "FastSaw", "SlowSaw", "BrightSaw",
+            "SoftSine", "SquareSaw", "SquareFifth",
+            "Blip"
+    };
+
+    static class MyVoiceDescription extends VoiceDescription {
+        String[] tags = {
+                "electronic", "filter", "analog", "subtractive"
+        };
+
+        public MyVoiceDescription() {
+            super(DualOscillatorSynthVoice.class.getName(), presetNames);
+        }
+
+        @Override
+        public UnitVoice createUnitVoice() {
+            return new DualOscillatorSynthVoice();
+        }
+
+        @Override
+        public String[] getTags(int presetIndex) {
+            return tags;
+        }
+
+        @Override
+        public String getVoiceClassName() {
+            return DualOscillatorSynthVoice.class.getName();
+        }
+    }
+
+    public static VoiceDescription getVoiceDescription() {
+        if (voiceDescription == null) {
+            voiceDescription = new MyVoiceDescription();
+        }
+        return voiceDescription;
+    }
+
+
+}
diff --git a/src/com/jsyn/instruments/JSynInstrumentLibrary.java b/src/com/jsyn/instruments/JSynInstrumentLibrary.java
index c5ed91e..9f111c3 100644
--- a/src/com/jsyn/instruments/JSynInstrumentLibrary.java
+++ b/src/com/jsyn/instruments/JSynInstrumentLibrary.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -22,15 +22,18 @@ import com.jsyn.util.VoiceDescription;
 
 /**
  * Stock instruments provided with the JSyn distribution.
- * 
+ *
  * @author Phil Burk (C) 2011 Mobileer Inc
  * @see InstrumentBrowser
  */
 
 public class JSynInstrumentLibrary implements InstrumentLibrary {
     static VoiceDescription[] descriptions = {
-            WaveShapingVoice.getVoiceDescription(), SubtractiveSynthVoice.getVoiceDescription(),
-            NoiseHit.getVoiceDescription(), DrumWoodFM.getVoiceDescription()
+            WaveShapingVoice.getVoiceDescription(),
+            SubtractiveSynthVoice.getVoiceDescription(),
+            DualOscillatorSynthVoice.getVoiceDescription(),
+            NoiseHit.getVoiceDescription(),
+            DrumWoodFM.getVoiceDescription()
     };
 
     @Override
diff --git a/src/com/jsyn/instruments/SubtractiveSynthVoice.java b/src/com/jsyn/instruments/SubtractiveSynthVoice.java
index af3329e..5cfc4b9 100644
--- a/src/com/jsyn/instruments/SubtractiveSynthVoice.java
+++ b/src/com/jsyn/instruments/SubtractiveSynthVoice.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -30,13 +30,12 @@ import com.jsyn.util.VoiceDescription;
 import com.softsynth.shared.time.TimeStamp;
 
 /**
- * Typical synthesizer voice with an oscillator and resonant filter. Modulate the amplitude and
+ * Typical synthesizer voice with one oscillator and a biquad resonant filter. Modulate the amplitude and
  * filter using DAHDSR envelopes.
- * 
+ *
  * @author Phil Burk (C) 2010 Mobileer Inc
  */
 public class SubtractiveSynthVoice extends Circuit implements UnitVoice {
-    private static final long serialVersionUID = -2704222221111608377L;
     private UnitOscillator osc;
     private FilterLowPass filter;
     private EnvelopeDAHDSR ampEnv;
diff --git a/src/com/jsyn/midi/MessageParser.java b/src/com/jsyn/midi/MessageParser.java
index 43d10c8..d0f5d4d 100644
--- a/src/com/jsyn/midi/MessageParser.java
+++ b/src/com/jsyn/midi/MessageParser.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -18,10 +18,15 @@ package com.jsyn.midi;
 
 /**
  * Parse the message and call the appropriate method to handle it.
- * 
+ *
  * @author Phil Burk (C) 2010 Mobileer Inc
  */
 public class MessageParser {
+    private int[] parameterIndices = new int[MidiConstants.MAX_CHANNELS];
+    private int[] parameterValues = new int[MidiConstants.MAX_CHANNELS];
+    private int BIT_NON_RPM = 1 << 14;
+    private int MASK_14BIT = (1 << 14) - 1;
+
     public void parse(byte[] message) {
         int status = message[0];
         int command = status & 0xF0;
@@ -41,27 +46,102 @@ public class MessageParser {
                 noteOff(channel, message[1], message[2]);
                 break;
 
+            case MidiConstants.POLYPHONIC_AFTERTOUCH:
+                polyphonicAftertouch(channel, message[1], message[2]);
+                break;
+
+            case MidiConstants.CHANNEL_PRESSURE:
+                channelPressure(channel, message[1]);
+                break;
+
             case MidiConstants.CONTROL_CHANGE:
-                controlChange(channel, message[1], message[2]);
+                rawControlChange(channel, message[1], message[2]);
+                break;
+
+            case MidiConstants.PROGRAM_CHANGE:
+                programChange(channel, message[1]);
                 break;
 
             case MidiConstants.PITCH_BEND:
-                int bend = (((message[2]) & 0x007F) << 7) + ((message[1]) & 0x007F);
+                int bend = (message[2] << 7) + message[1];
                 pitchBend(channel, bend);
                 break;
         }
 
     }
 
+    public void rawControlChange(int channel, int index, int value) {
+        int paramIndex;
+        int paramValue;
+        switch(index) {
+            case MidiConstants.CONTROLLER_DATA_ENTRY:
+                parameterValues[channel] = value << 7;
+                fireParameterChange(channel);
+                break;
+            case MidiConstants.CONTROLLER_DATA_ENTRY_LSB:
+                paramValue = parameterValues[channel] & ~0x7F;
+                paramValue |= value;
+                parameterValues[channel] = paramValue;
+                fireParameterChange(channel);
+                break;
+            case MidiConstants.CONTROLLER_NRPN_LSB:
+                paramIndex = parameterIndices[channel] & ~0x7F;
+                paramIndex |= value | BIT_NON_RPM;
+                parameterIndices[channel] = paramIndex;
+                break;
+            case MidiConstants.CONTROLLER_NRPN_MSB:
+                parameterIndices[channel] = (value << 7) | BIT_NON_RPM;;
+                break;
+            case MidiConstants.CONTROLLER_RPN_LSB:
+                paramIndex = parameterIndices[channel] & ~0x7F;
+                paramIndex |= value;
+                parameterIndices[channel] = paramIndex;
+                break;
+            case MidiConstants.CONTROLLER_RPN_MSB:
+                parameterIndices[channel] = value << 7;
+                break;
+            default:
+                controlChange(channel, index, value);
+                break;
+
+        }
+    }
+
+    private void fireParameterChange(int channel) {
+        int paramIndex;
+        paramIndex = parameterIndices[channel];
+        if ((paramIndex & BIT_NON_RPM) == 0) {
+            registeredParameter(channel, paramIndex, parameterValues[channel]);
+        } else {
+            nonRegisteredParameter(channel, paramIndex & MASK_14BIT, parameterValues[channel]);
+        }
+    }
+
+    public void nonRegisteredParameter(int channel, int index14, int value14) {
+    }
+
+    public void registeredParameter(int channel, int index14, int value14) {
+    }
+
     public void pitchBend(int channel, int bend) {
     }
 
+    public void programChange(int channel, int program) {
+    }
+
+    public void polyphonicAftertouch(int channel, int pitch, int pressure) {
+    }
+
+    public void channelPressure(int channel, int pressure) {
+    }
+
     public void controlChange(int channel, int index, int value) {
     }
 
     public void noteOn(int channel, int pitch, int velocity) {
     }
 
+    // If a NOTE_ON with zero velocity is received then noteOff will be called.
     public void noteOff(int channel, int pitch, int velocity) {
     }
 }
diff --git a/src/com/jsyn/midi/MidiConstants.java b/src/com/jsyn/midi/MidiConstants.java
index dae9390..8c92119 100644
--- a/src/com/jsyn/midi/MidiConstants.java
+++ b/src/com/jsyn/midi/MidiConstants.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -18,10 +18,12 @@ package com.jsyn.midi;
 
 /**
  * Constants that define the MIDI standard.
- * 
+ *
  * @author Phil Burk (C) 2010 Mobileer Inc
  */
 public class MidiConstants {
+
+    public static final int MAX_CHANNELS = 16;
     // Basic commands.
     public static final int NOTE_OFF = 0x80;
     public static final int NOTE_ON = 0x90;
@@ -29,10 +31,33 @@ public class MidiConstants {
     public static final int CONTROL_CHANGE = 0xB0;
     public static final int PROGRAM_CHANGE = 0xC0;
     public static final int CHANNEL_AFTERTOUCH = 0xD0;
+    public static final int CHANNEL_PRESSURE = CHANNEL_AFTERTOUCH;
     public static final int PITCH_BEND = 0xE0;
     public static final int SYSTEM_COMMON = 0xF0;
 
-    public static final int PITCH_BEND_CENTER = 8192;
+    public static final int PITCH_BEND_CENTER = 0x2000;
+
+    public static final int CONTROLLER_BANK_SELECT = 0;
+    public static final int CONTROLLER_MOD_WHEEL = 1;
+    public static final int CONTROLLER_BREATH = 2;
+    public static final int CONTROLLER_DATA_ENTRY = 6;
+    public static final int CONTROLLER_VOLUME = 7;
+    public static final int CONTROLLER_PAN = 10;
+
+    public static final int CONTROLLER_LSB_OFFSET = 32;
+    public static final int CONTROLLER_DATA_ENTRY_LSB = CONTROLLER_DATA_ENTRY + CONTROLLER_LSB_OFFSET;
+
+    public static final int CONTROLLER_TIMBRE = 74; // Often used by MPE for Y axis control.
+
+    public static final int CONTROLLER_DATA_INCREMENT = 96;
+    public static final int CONTROLLER_DATA_DECREMENT = 97;
+    public static final int CONTROLLER_NRPN_LSB = 98;
+    public static final int CONTROLLER_NRPN_MSB = 99;
+    public static final int CONTROLLER_RPN_LSB = 100;
+    public static final int CONTROLLER_RPN_MSB = 101;
+
+    public static final int RPN_BEND_RANGE = 0;
+    public static final int RPN_FINE_TUNING = 1;
 
     public static final String PITCH_NAMES[] = {
             "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"
diff --git a/src/com/jsyn/midi/MidiSynthesizer.java b/src/com/jsyn/midi/MidiSynthesizer.java
new file mode 100644
index 0000000..e011430
--- /dev/null
+++ b/src/com/jsyn/midi/MidiSynthesizer.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright 2016 Phil Burk, Mobileer Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jsyn.midi;
+
+import com.jsyn.util.MultiChannelSynthesizer;
+
+public class MidiSynthesizer extends MessageParser {
+
+    private MultiChannelSynthesizer multiSynth;
+
+    public MidiSynthesizer(MultiChannelSynthesizer multiSynth) {
+        this.multiSynth = multiSynth;
+    }
+
+    @Override
+    public void controlChange(int channel, int index, int value) {
+        //System.out.println("controlChange(" + channel + ", " + index + ", " + value + ")");
+        double normalized = value * (1.0 / 127.0);
+        switch (index) {
+            case MidiConstants.CONTROLLER_MOD_WHEEL:
+                double vibratoDepth = 0.1 * normalized;
+                System.out.println( "vibratoDepth = " + vibratoDepth );
+                multiSynth.setVibratoDepth(channel, vibratoDepth);
+                break;
+            case MidiConstants.CONTROLLER_TIMBRE:
+                multiSynth.setTimbre(channel, normalized);
+                break;
+            case MidiConstants.CONTROLLER_VOLUME:
+                multiSynth.setVolume(channel, normalized);
+                break;
+            case MidiConstants.CONTROLLER_PAN:
+                // convert to -1 to +1 range
+                multiSynth.setPan(channel, (normalized * 2.0) - 1.0);
+                break;
+        }
+    }
+
+    @Override
+    public void registeredParameter(int channel, int index14, int value14) {
+        switch(index14) {
+            case MidiConstants.RPN_BEND_RANGE:
+                int semitones = value14 >> 7;
+                int cents = value14 & 0x7F;
+                double bendRange = semitones + (cents * 0.01);
+                multiSynth.setBendRange(channel, bendRange);
+                break;
+            default:
+                break;
+        }
+    }
+
+    @Override
+    public void programChange(int channel, int program) {
+        multiSynth.programChange(channel, program);
+    }
+
+    @Override
+    public void channelPressure(int channel, int value) {
+        double normalized = value * (1.0 / 127.0);
+        multiSynth.setPressure(channel, normalized);
+    }
+
+    @Override
+    public void noteOff(int channel, int noteNumber, int velocity) {
+        multiSynth.noteOff(channel, noteNumber, velocity);
+    }
+
+    @Override
+    public void noteOn(int channel, int noteNumber, int velocity) {
+        multiSynth.noteOn(channel, noteNumber, velocity);
+    }
+
+    @Override
+    public void pitchBend(int channel, int bend) {
+        double offset = (bend - MidiConstants.PITCH_BEND_CENTER)
+                * (1.0 / (MidiConstants.PITCH_BEND_CENTER));
+        multiSynth.setPitchBend(channel, offset);
+    }
+
+    public void onReceive(byte[] bytes, int i, int length) {
+        parse(bytes); // TODO
+    }
+
+}
diff --git a/src/com/jsyn/ports/InputMixingBlockPart.java b/src/com/jsyn/ports/InputMixingBlockPart.java
index 3211342..5b54b99 100644
--- a/src/com/jsyn/ports/InputMixingBlockPart.java
+++ b/src/com/jsyn/ports/InputMixingBlockPart.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -23,16 +23,18 @@ import com.jsyn.unitgen.UnitGenerator;
 
 /**
  * A UnitInputPort has an array of these, one for each part.
- * 
+ *
  * @author Phil Burk 2009 Mobileer Inc
  */
 
 public class InputMixingBlockPart extends PortBlockPart {
     private double[] mixer = new double[Synthesizer.FRAMES_PER_BLOCK];
     private double current;
+    private UnitInputPort unitInputPort;
 
-    InputMixingBlockPart(UnitBlockPort unitBlockPort, double defaultValue) {
-        super(unitBlockPort, defaultValue);
+    InputMixingBlockPart(UnitInputPort unitInputPort, double defaultValue) {
+        super(unitInputPort, defaultValue);
+        this.unitInputPort = unitInputPort;
     }
 
     @Override
@@ -52,30 +54,32 @@ public class InputMixingBlockPart extends PortBlockPart {
         int numConnections = getConnectionCount();
         // System.out.println("numConnection = " + numConnections + " for " +
         // this );
-        if (numConnections == 0)
-        // No connection so just use our own data.
-        {
+        if (numConnections == 0) {
+            // No connection so just use our own data.
             result = super.getValues();
-        } else if (numConnections == 1)
-        // Grab values from one connected port.
-        {
-            PortBlockPart otherPart = getConnection(0);
-            result = otherPart.getValues();
-        } else
-        // Mix all of the inputs.
-        {
-            PortBlockPart otherPart = getConnection(0);
-            double[] inputs = otherPart.getValues();
+        } else {
+            // Mix all of the connected ports.
+            double[] inputs;
+            int jCon = 0;
+            PortBlockPart otherPart;
+            // Choose value to initialize the mixer array.
+            if (unitInputPort.isValueAdded()) {
+                inputs = super.getValues();  // prime mixer with the set() values
+                jCon = 0;
+            } else {
+                otherPart = getConnection(jCon);
+                inputs = otherPart.getValues(); // prime mixer with first connected
+                jCon = 1;
+            }
             for (int i = 0; i < mixer.length; i++) {
-                mixer[i] = inputs[i]; // set directly instead of zeroing first
+                mixer[i] = inputs[i];
             }
             // Now mix in the remaining inputs.
-            for (int jCon = 1; jCon < numConnections; jCon++) {
+            for (; jCon < numConnections; jCon++) {
                 otherPart = getConnection(jCon);
-
                 inputs = otherPart.getValues();
                 for (int i = 0; i < mixer.length; i++) {
-                    mixer[i] += inputs[i]; // mix with previous inputs
+                    mixer[i] += inputs[i];
                 }
             }
             result = mixer;
diff --git a/src/com/jsyn/ports/UnitGatePort.java b/src/com/jsyn/ports/UnitGatePort.java
index 43d5e7f..700aef8 100644
--- a/src/com/jsyn/ports/UnitGatePort.java
+++ b/src/com/jsyn/ports/UnitGatePort.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -97,7 +97,7 @@ public class UnitGatePort extends UnitInputPort {
 
     /**
      * This is called by UnitGenerators. It sets the off value that can be tested using isOff().
-     * 
+     *
      * @param i
      * @return true if triggered by a positive edge.
      */
@@ -129,7 +129,7 @@ public class UnitGatePort extends UnitInputPort {
     /**
      * Request the containing UnitGenerator be disabled when checkAutoDisabled() is called. This can
      * be used to reduce CPU load.
-     * 
+     *
      * @param autoDisableEnabled
      */
     public void setAutoDisableEnabled(boolean autoDisableEnabled) {
diff --git a/src/com/jsyn/ports/UnitInputPort.java b/src/com/jsyn/ports/UnitInputPort.java
index 93a7f7a..3eda1f6 100644
--- a/src/com/jsyn/ports/UnitInputPort.java
+++ b/src/com/jsyn/ports/UnitInputPort.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -23,15 +23,15 @@ import com.softsynth.shared.time.TimeStamp;
 
 /**
  * A port that is used to pass values into a UnitGenerator.
- * 
+ *
  * @author Phil Burk 2009 Mobileer Inc
  */
 public class UnitInputPort extends UnitBlockPort implements ConnectableInput, SettablePort {
     private double minimum = 0.0;
     private double maximum = 1.0;
     private double defaultValue = 0.0;
-
     private double[] setValues;
+    private boolean valueAdded = false;
 
     /**
      * @param numParts typically 1, use 2 for stereo ports
@@ -69,7 +69,7 @@ public class UnitInputPort extends UnitBlockPort implements ConnectableInput, Se
 
     /**
      * This is used internally by the SynthesisEngine to execute units based on their connections.
-     * 
+     *
      * @param frameCount
      * @param start
      * @param limit
@@ -128,7 +128,7 @@ public class UnitInputPort extends UnitBlockPort implements ConnectableInput, Se
 
     /**
      * Value of a port based on the set() calls. Not affected by connected ports.
-     * 
+     *
      * @param partNum
      * @return value as set
      */
@@ -144,7 +144,7 @@ public class UnitInputPort extends UnitBlockPort implements ConnectableInput, Se
     /**
      * The minimum and maximum are only used when setting up knobs or other control systems. The
      * internal values are not clipped to this range.
-     * 
+     *
      * @param maximum
      */
     public void setMaximum(double maximum) {
@@ -170,7 +170,7 @@ public class UnitInputPort extends UnitBlockPort implements ConnectableInput, Se
     /**
      * Convenience function for setting limits on a port. These limits are recommended values when
      * setting up a GUI. It is possible to set a port to a value outside these limits.
-     * 
+     *
      * @param minimum
      * @param value default value, will be clipped to min/max
      * @param maximum
@@ -187,6 +187,25 @@ public class UnitInputPort extends UnitBlockPort implements ConnectableInput, Se
         setup(other.getMinimum(), other.getDefault(), other.getMaximum());
     }
 
+    public boolean isValueAdded() {
+        return valueAdded;
+    }
+
+    /**
+     * If set false then the set() value will be ignored when other ports are connected to this port.
+     * The sum of the connected port values will be used instead.
+     *
+     * If set true then the set() value will be added to the sum of the connected port values.
+     * This is useful when you want to modulate the set value.
+     *
+     * The default is false.
+     *
+     * @param valueAdded
+     */
+    public void setValueAdded(boolean valueAdded) {
+        this.valueAdded = valueAdded;
+    }
+
     public void connect(int thisPartNum, UnitOutputPort otherPort, int otherPartNum,
             TimeStamp timeStamp) {
         otherPort.connect(otherPartNum, this, thisPartNum, timeStamp);
diff --git a/src/com/jsyn/scope/AudioScope.java b/src/com/jsyn/scope/AudioScope.java
index 32268cd..9ab4a73 100644
--- a/src/com/jsyn/scope/AudioScope.java
+++ b/src/com/jsyn/scope/AudioScope.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -27,7 +27,7 @@ import com.jsyn.scope.swing.AudioScopeView;
 // TODO Continuous capture
 /**
  * Digital oscilloscope for JSyn.
- * 
+ *
  * @author Phil Burk (C) 2010 Mobileer Inc
  */
 public class AudioScope {
@@ -90,7 +90,11 @@ public class AudioScope {
         return getModel().getTriggerModel().getLevelModel().getDoubleValue();
     }
 
-    public void setViewMode(ViewMode waveform) {
+    /**
+     * Not yet implemented.
+     * @param waveform
+     */
+    public void setViewMode(ViewMode viewMode) {
         // TODO Auto-generated method stub
 
     }
diff --git a/src/com/jsyn/scope/TriggerModel.java b/src/com/jsyn/scope/TriggerModel.java
index 7081b2c..0367d71 100644
--- a/src/com/jsyn/scope/TriggerModel.java
+++ b/src/com/jsyn/scope/TriggerModel.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -16,7 +16,6 @@
 
 package com.jsyn.scope;
 
-import javax.swing.ComboBoxModel;
 import javax.swing.DefaultComboBoxModel;
 
 import com.jsyn.scope.AudioScope.TriggerMode;
diff --git a/src/com/jsyn/scope/swing/AudioScopeView.java b/src/com/jsyn/scope/swing/AudioScopeView.java
index 31f1264..ec1afa3 100644
--- a/src/com/jsyn/scope/swing/AudioScopeView.java
+++ b/src/com/jsyn/scope/swing/AudioScopeView.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -77,7 +77,7 @@ public class AudioScopeView extends JPanel {
         setMaximumSize(new Dimension(1200, 300));
     }
 
-    /** @deprecated */
+    /** @deprecated Use setControlsVisible() instead. */
     @Deprecated
     public void setShowControls(boolean show) {
         setControlsVisible(show);
diff --git a/src/com/jsyn/scope/swing/ScopeTriggerPanel.java b/src/com/jsyn/scope/swing/ScopeTriggerPanel.java
index a5f1541..9c22aa1 100644
--- a/src/com/jsyn/scope/swing/ScopeTriggerPanel.java
+++ b/src/com/jsyn/scope/swing/ScopeTriggerPanel.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -18,7 +18,6 @@ package com.jsyn.scope.swing;
 
 import java.awt.BorderLayout;
 
-import javax.swing.ComboBoxModel;
 import javax.swing.DefaultComboBoxModel;
 import javax.swing.JComboBox;
 import javax.swing.JPanel;
diff --git a/src/com/jsyn/swing/EnvelopeEditorBox.java b/src/com/jsyn/swing/EnvelopeEditorBox.java
index 44fe53c..aab5762 100644
--- a/src/com/jsyn/swing/EnvelopeEditorBox.java
+++ b/src/com/jsyn/swing/EnvelopeEditorBox.java
@@ -282,7 +282,7 @@ public class EnvelopeEditorBox extends XYController implements MouseListener, Mo
             {
                 dragIndex = pnt;
                 if (dragIndex <= 0)
-                    dragLowLimit = 0.0; // FIXME
+                    dragLowLimit = 0.0; // FIXME envelope drag limit
                 else
                     dragLowLimit = xPicked - points.getPoint(dragIndex)[0];
                 dragHighLimit = xPicked + (maximumXRange - points.getTotalDuration());
diff --git a/src/com/jsyn/swing/SoundTweaker.java b/src/com/jsyn/swing/SoundTweaker.java
index d41946d..043677e 100644
--- a/src/com/jsyn/swing/SoundTweaker.java
+++ b/src/com/jsyn/swing/SoundTweaker.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -45,13 +45,12 @@ public class SoundTweaker extends JPanel {
         this.synth = synth;
         this.source = source;
 
-        setLayout(new GridLayout(0, 1));
+        setLayout(new GridLayout(0, 2));
 
         UnitGenerator ugen = source.getUnitGenerator();
         ArrayList<Component> sliders = new ArrayList<Component>();
 
         add(new JLabel(title));
-        // Arrange the faders in a stack.
 
         if (source instanceof Instrument) {
             add(keyboard = createPolyphonicKeyboard());
@@ -59,6 +58,7 @@ public class SoundTweaker extends JPanel {
             add(keyboard = createMonophonicKeyboard());
         }
 
+        // Arrange the faders in a stack.
         // Iterate through the ports.
         for (UnitPort port : ugen.getPorts()) {
             if (port instanceof UnitInputPort) {
@@ -90,13 +90,11 @@ public class SoundTweaker extends JPanel {
         ASCIIMusicKeyboard keyboard = new ASCIIMusicKeyboard() {
             @Override
             public void keyOff(int pitch) {
-                logger.info("-------------- keyOff " + pitch);
                 ((Instrument) source).noteOff(pitch, synth.createTimeStamp());
             }
 
             @Override
             public void keyOn(int pitch) {
-                logger.info("-------------- keyOn " + pitch);
                 double freq = AudioMath.pitchToFrequency(pitch);
                 ((Instrument) source).noteOn(pitch, freq, 0.5, synth.createTimeStamp());
             }
diff --git a/src/com/jsyn/unitgen/Circuit.java b/src/com/jsyn/unitgen/Circuit.java
index a501600..c5a1dcf 100644
--- a/src/com/jsyn/unitgen/Circuit.java
+++ b/src/com/jsyn/unitgen/Circuit.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -17,17 +17,21 @@
 package com.jsyn.unitgen;
 
 import java.util.ArrayList;
+import java.util.LinkedHashMap;
 
 import com.jsyn.engine.SynthesisEngine;
+import com.jsyn.ports.UnitPort;
 
 /**
  * Contains a list of units that are executed together.
- * 
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc
  */
 public class Circuit extends UnitGenerator {
     private ArrayList<UnitGenerator> units = new ArrayList<UnitGenerator>();
 
+    private final LinkedHashMap<String, UnitPort> portAliases = new LinkedHashMap<String, UnitPort>();
+
     @Override
     public void generate(int start, int limit) {
         for (UnitGenerator unit : units) {
@@ -57,6 +61,11 @@ public class Circuit extends UnitGenerator {
         }
     }
 
+    /**
+     * @deprecated ignored, frameRate comes from the SynthesisEngine
+     * @param rate
+     */
+    @Deprecated
     @Override
     public void setFrameRate(int frameRate) {
         super.setFrameRate(frameRate);
@@ -83,4 +92,31 @@ public class Circuit extends UnitGenerator {
 
     public void usePreset(int presetIndex) {
     }
+
+
+    /**
+     * Add an alternate name for looking up a port.
+     * @param port
+     * @param alias
+     */
+    public void addPortAlias(UnitPort port, String alias) {
+        // Store in a hash table by an alternate name.
+        portAliases.put(alias.toLowerCase(), port);
+    }
+
+
+    /**
+     * Case-insensitive search for a port by its name or alias.
+     * @param portName
+     * @return matching port or null
+     */
+    @Override
+    public UnitPort getPortByName(String portName) {
+        UnitPort port = super.getPortByName(portName);
+        if (port == null) {
+            port = portAliases.get(portName.toLowerCase());
+        }
+        return port;
+    }
+
 }
diff --git a/src/com/jsyn/unitgen/EnvelopeDAHDSR.java b/src/com/jsyn/unitgen/EnvelopeDAHDSR.java
index 6acd763..c5ebe83 100644
--- a/src/com/jsyn/unitgen/EnvelopeDAHDSR.java
+++ b/src/com/jsyn/unitgen/EnvelopeDAHDSR.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -30,7 +30,7 @@ import com.jsyn.ports.UnitOutputPort;
  * exponential Release will never reach 0.0. But when it reaches -96 dB the DAHDSR just sets its
  * output to 0.0 and stops. There is an example program in the ZIP archive called HearDAHDSR. It
  * drives a DAHDSR with a square wave.
- * 
+ *
  * @author Phil Burk (C) 2010 Mobileer Inc
  * @see SegmentedEnvelope
  */
diff --git a/src/com/jsyn/unitgen/FilterFourPoles.java b/src/com/jsyn/unitgen/FilterFourPoles.java
index d4f80f4..39a47c7 100644
--- a/src/com/jsyn/unitgen/FilterFourPoles.java
+++ b/src/com/jsyn/unitgen/FilterFourPoles.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -20,13 +20,13 @@ import com.jsyn.ports.UnitInputPort;
 
 /**
  * Resonant filter in the style of the Moog ladder filter. This implementation is loosely based on:
- * http://www.musicdsp.org/archive.php?classid=3#26 
+ * http://www.musicdsp.org/archive.php?classid=3#26
  * More interesting reading:
  * http://dafx04.na.infn.it/WebProc/Proc/P_061.pdf
  * http://www.acoustics.ed.ac.uk/wp-content/uploads/AMT_MSc_FinalProjects
  * /2012__Daly__AMT_MSc_FinalProject_MoogVCF.pdf
  * http://www.music.mcgill.ca/~ich/research/misc/papers/cr1071.pdf
- * 
+ *
  * @author Phil Burk (C) 2014 Mobileer Inc
  * @see FilterLowPass
  */
@@ -37,6 +37,14 @@ public class FilterFourPoles extends TunableFilter {
     private static final double MINIMUM_FREQUENCY = 1.0; // blows up if near 0.01
     private static final double MINIMUM_Q = 0.00001;
 
+    //private static final double SATURATION_COEFFICIENT = 0.1666667;
+    private static final double SATURATION_COEFFICIENT = 0.2;
+    // Inflection point where slope is zero.
+    private static final double SATURATION_UPPER_INPUT = 1.0 / Math.sqrt(3.0 * SATURATION_COEFFICIENT);
+    private static final double SATURATION_LOWER_INPUT = 0.0 - SATURATION_UPPER_INPUT;
+    private static final double SATURATION_UPPER_OUTPUT = cubicPolynomial(SATURATION_UPPER_INPUT);
+    private static final double SATURATION_LOWER_OUTPUT = cubicPolynomial(SATURATION_LOWER_INPUT);
+
     private double x1;
     private double x2;
     private double x3;
@@ -57,6 +65,7 @@ public class FilterFourPoles extends TunableFilter {
 
     public FilterFourPoles() {
         addPort(Q = new UnitInputPort("Q"));
+        frequency.setup(40.0, DEFAULT_FREQUENCY, 4000.0);
         Q.setup(0.1, 2.0, 10.0);
     }
 
@@ -111,7 +120,6 @@ public class FilterFourPoles extends TunableFilter {
                 oneSample(0.0);
             }
             oneSample(x0);
-
             outputs[i] = y4;
         }
 
@@ -143,8 +151,35 @@ public class FilterFourPoles extends TunableFilter {
         this.oversampled = oversampled;
     }
 
-    private double clip(double x) {
-        return x - (x * x * x * 0.1666667);
+    // Soft saturation. This used to blow up the filter!
+    private static double cubicPolynomial(double x) {
+        return x - (x * x * x * SATURATION_COEFFICIENT);
     }
 
+    private static double clip(double x) {
+        if (x > SATURATION_UPPER_INPUT) {
+            return SATURATION_UPPER_OUTPUT;
+        } else if (x < SATURATION_LOWER_INPUT) {
+            return SATURATION_LOWER_OUTPUT;
+        } else {
+            return cubicPolynomial(x);
+        }
+    }
+
+    public void reset() {
+        x1 = 0.0;
+        x2 = 0.0;
+        x3 = 0.0;
+        x4 = 0.0;
+        y1 = 0.0;
+        y2 = 0.0;
+        y3 = 0.0;
+        y4 = 0.0;
+
+        previousFrequency = 0.0;
+        previousQ = 0.0;
+        f = 0.0;
+        fTo4th = 0.0;
+        feedback = 0.0;
+    }
 }
diff --git a/src/com/jsyn/unitgen/LineOut.java b/src/com/jsyn/unitgen/LineOut.java
index 489033e..d58f211 100644
--- a/src/com/jsyn/unitgen/LineOut.java
+++ b/src/com/jsyn/unitgen/LineOut.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -20,7 +20,7 @@ import com.jsyn.ports.UnitInputPort;
 
 /**
  * Input audio is sent to the external audio output device.
- * 
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc
  */
 public class LineOut extends UnitGenerator implements UnitSink {
diff --git a/src/com/jsyn/unitgen/LinearRamp.java b/src/com/jsyn/unitgen/LinearRamp.java
index 438adf6..cad53d5 100644
--- a/src/com/jsyn/unitgen/LinearRamp.java
+++ b/src/com/jsyn/unitgen/LinearRamp.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -26,7 +26,7 @@ import com.jsyn.ports.UnitVariablePort;
  * value toward the value of input. An internal phase value will go from 0.0 to 1.0 at a rate
  * controlled by time. When the internal phase reaches 1.0, the output will equal input.
  * <P>
- * 
+ *
  * @author (C) 1997 Phil Burk, SoftSynth.com
  * @see ExponentialRamp
  * @see AsymptoticRamp
@@ -52,33 +52,41 @@ public class LinearRamp extends UnitFilter {
     public void generate(int start, int limit) {
         double[] outputs = output.getValues();
         double currentInput = input.getValues()[0];
-        double currentTime = time.getValues()[0];
         double currentValue = current.getValue();
 
-        if (currentTime != timeHeld) {
-            rate = convertTimeToRate(currentTime);
-            timeHeld = currentTime;
-        }
-
-        /* If input has changed, start new segment */
-        if (currentInput != target) /*
-                                     * Equality check is OK because we set them exactly equal below.
-                                     */
+        // If input has changed, start new segment.
+        // Equality check is OK because we set them exactly equal below.
+        if (currentInput != target)
         {
             source = currentValue;
             phase = 0.0;
             target = currentInput;
         }
 
-        for (int i = start; i < limit; i++) {
-            if (phase < 1.0) {
-                /* Interpolate current. */
-                currentValue = source + (phase * (target - source));
-                phase += rate;
-            } else {
-                currentValue = target;
+        if (currentValue == target) {
+            // at end of ramp
+            for (int i = start; i < limit; i++) {
+                outputs[i] = currentValue;
+            }
+        } else {
+            // in middle of ramp
+            double currentTime = time.getValues()[0];
+            // Has time changed?
+            if (currentTime != timeHeld) {
+                rate = convertTimeToRate(currentTime);
+                timeHeld = currentTime;
+            }
+
+            for (int i = start; i < limit; i++) {
+                if (phase < 1.0) {
+                    /* Interpolate current. */
+                    currentValue = source + (phase * (target - source));
+                    phase += rate;
+                } else {
+                    currentValue = target;
+                }
+                outputs[i] = currentValue;
             }
-            outputs[i] = currentValue;
         }
 
         current.setValue(currentValue);
diff --git a/src/com/jsyn/unitgen/MorphingOscillatorBL.java b/src/com/jsyn/unitgen/MorphingOscillatorBL.java
new file mode 100644
index 0000000..7ca440d
--- /dev/null
+++ b/src/com/jsyn/unitgen/MorphingOscillatorBL.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2009 Phil Burk, Mobileer Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jsyn.unitgen;
+
+import com.jsyn.engine.MultiTable;
+import com.jsyn.ports.UnitInputPort;
+
+/**
+ * Oscillator that can change its shape from sine to sawtooth to pulse.
+ *
+ * @author Phil Burk (C) 2016 Mobileer Inc
+ */
+public class MorphingOscillatorBL extends PulseOscillatorBL {
+    /**
+     * Controls the shape of the waveform.
+     * The shape varies continuously from a sine wave at -1.0,
+     * to a sawtooth at 0.0 to a pulse wave at 1.0.
+     */
+    public UnitInputPort shape;
+
+    public MorphingOscillatorBL() {
+        addPort(shape = new UnitInputPort("Shape"));
+        shape.setMinimum(-1.0);
+        shape.setMaximum(1.0);
+    }
+
+    @Override
+    protected double generateBL(MultiTable multiTable, double currentPhase,
+            double positivePhaseIncrement, double flevel, int i) {
+        double[] shapes = shape.getValues();
+        double shape = shapes[i];
+
+        if (shape < 0.0) {
+            // Squeeze flevel towards the pure sine table.
+            flevel += flevel * shape;
+            return multiTable.calculateSawtooth(currentPhase, positivePhaseIncrement, flevel);
+        } else {
+            double[] widths = width.getValues();
+            double width = widths[i];
+            width = (width > 0.999) ? 0.999 : ((width < -0.999) ? -0.999 : width);
+
+            double val1 = multiTable.calculateSawtooth(currentPhase, positivePhaseIncrement, flevel);
+            // Generate second sawtooth so we can add them together.
+            double phase2 = currentPhase + 1.0 - width; // 180 degrees out of phase
+            if (phase2 >= 1.0) {
+                phase2 -= 2.0;
+            }
+            double val2 = multiTable.calculateSawtooth(phase2, positivePhaseIncrement, flevel);
+
+            /*
+             * Need to adjust amplitude based on positive phaseInc. little less than half at
+             * Nyquist/2.0!
+             */
+            double scale = 1.0 - positivePhaseIncrement;
+            return scale * (val1 - ((val2 + width) * shape)); // apply shape morphing
+        }
+    }
+}
diff --git a/src/com/jsyn/unitgen/PitchToFrequency.java b/src/com/jsyn/unitgen/PitchToFrequency.java
new file mode 100644
index 0000000..9086749
--- /dev/null
+++ b/src/com/jsyn/unitgen/PitchToFrequency.java
@@ -0,0 +1,26 @@
+package com.jsyn.unitgen;
+
+import com.softsynth.math.AudioMath;
+
+public class PitchToFrequency extends PowerOfTwo {
+
+    public PitchToFrequency() {
+        input.setup(0.0, 60.0, 127.0);
+    }
+
+    /**
+     * Convert from MIDI pitch to an octave offset from Concert A.
+     */
+    @Override
+    public double adjustInput(double in) {
+        return (in - AudioMath.CONCERT_A_PITCH) * (1.0/12.0);
+    }
+
+    /**
+     * Convert scaler to a frequency relative to Concert A.
+     */
+    @Override
+    public double adjustOutput(double out) {
+        return out * AudioMath.getConcertAFrequency();
+    }
+}
diff --git a/src/com/jsyn/unitgen/PowerOfTwo.java b/src/com/jsyn/unitgen/PowerOfTwo.java
index 5f1b4cd..5916860 100644
--- a/src/com/jsyn/unitgen/PowerOfTwo.java
+++ b/src/com/jsyn/unitgen/PowerOfTwo.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -22,18 +22,23 @@ import com.jsyn.ports.UnitOutputPort;
 /**
  * output = (2.0^input) This is useful for converting a pitch modulation value into a frequency
  * scaler. An input value of +1.0 will output 2.0 for an octave increase. An input value of -1.0
- * will output 0.5 for an octave decrease. This implementation uses a table lookup to optimize for
+ * will output 0.5 for an octave decrease.
+ *
+ * This implementation uses a table lookup to optimize for
  * speed. It is accurate enough for tuning. It also checks to see if the current input value is the
  * same as the previous input value. If so then it reuses the previous computed value.
- * 
+ *
  * @author Phil Burk (C) 2010 Mobileer Inc
  */
 public class PowerOfTwo extends UnitGenerator {
+    /**
+     * Offset in octaves.
+     */
     public UnitInputPort input;
     public UnitOutputPort output;
 
     private static double[] table;
-    private static final int NUM_VALUES = 1024;
+    private static final int NUM_VALUES = 2048;
     // Cached computation.
     private double lastInput = 0.0;
     private double lastOutput = 1.0;
@@ -61,39 +66,43 @@ public class PowerOfTwo extends UnitGenerator {
         double[] inputs = input.getValues();
         double[] outputs = output.getValues();
 
-        if (true) {
-            for (int i = start; i < limit; i++) {
-                double in = inputs[i];
-                // Can we reuse a previously computed value?
-                if (in == lastInput) {
-                    outputs[i] = lastOutput;
-                } else {
-                    int octave = (int) Math.floor(in);
-                    double normal = in - octave;
-                    // Do table lookup.
-                    double findex = normal * NUM_VALUES;
-                    int index = (int) findex;
-                    double fraction = findex - index;
-                    double value = table[index] + (fraction * (table[index + 1] - table[index]));
+        for (int i = start; i < limit; i++) {
+            double in = inputs[i];
+            // Can we reuse a previously computed value?
+            if (in == lastInput) {
+                outputs[i] = lastOutput;
+            } else {
+                lastInput = in;
+                double adjustedInput = adjustInput(in);
+                int octave = (int) Math.floor(adjustedInput);
+                double normal = adjustedInput - octave;
+                // Do table lookup.
+                double findex = normal * NUM_VALUES;
+                int index = (int) findex;
+                double fraction = findex - index;
+                double value = table[index] + (fraction * (table[index + 1] - table[index]));
 
-                    // Adjust for octave.
-                    while (octave > 0) {
-                        octave -= 1;
-                        value *= 2.0;
-                    }
-                    while (octave < 0) {
-                        octave += 1;
-                        value *= 0.5;
-                    }
-                    outputs[i] = value;
-                    lastInput = in;
-                    lastOutput = value;
+                // Adjust for octave.
+                while (octave > 0) {
+                    octave -= 1;
+                    value *= 2.0;
                 }
-            }
-        } else {
-            for (int i = start; i < limit; i++) {
-                outputs[i] = Math.pow(2.0, inputs[i]);
+                while (octave < 0) {
+                    octave += 1;
+                    value *= 0.5;
+                }
+                double adjustedOutput = adjustOutput(value);
+                outputs[i] = adjustedOutput;
+                lastOutput = adjustedOutput;
             }
         }
     }
+
+    public double adjustInput(double in) {
+        return in;
+    }
+
+    public double adjustOutput(double out) {
+        return out;
+    }
 }
diff --git a/src/com/jsyn/unitgen/PulseOscillatorBL.java b/src/com/jsyn/unitgen/PulseOscillatorBL.java
index 43fe27b..c0e234c 100644
--- a/src/com/jsyn/unitgen/PulseOscillatorBL.java
+++ b/src/com/jsyn/unitgen/PulseOscillatorBL.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -20,11 +20,15 @@ import com.jsyn.engine.MultiTable;
 import com.jsyn.ports.UnitInputPort;
 
 /**
- * Pulse oscillator that uses two band limited sawtooth oscillators.
- * 
+ * Pulse oscillator that uses two band limited sawtooth waveforms.
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc
  */
 public class PulseOscillatorBL extends SawtoothOscillatorBL {
+    /** Controls the duty cycle of the pulse waveform.
+     * The width varies from -1.0 to +1.0.
+     * When width is zero the output is a square wave.
+     */
     public UnitInputPort width;
 
     public PulseOscillatorBL() {
@@ -48,7 +52,7 @@ public class PulseOscillatorBL extends SawtoothOscillatorBL {
         double val2 = multiTable.calculateSawtooth(phase2, positivePhaseIncrement, flevel);
 
         /*
-         * Need to adjust amplitude based on positive phaseInc. little less than half at
+         * Need to adjust amplitude based on positive phaseInc and width. little less than half at
          * Nyquist/2.0!
          */
         double scale = 1.0 - positivePhaseIncrement;
diff --git a/src/com/jsyn/unitgen/SawtoothOscillatorDPW.java b/src/com/jsyn/unitgen/SawtoothOscillatorDPW.java
index 6868c15..27d0c5a 100644
--- a/src/com/jsyn/unitgen/SawtoothOscillatorDPW.java
+++ b/src/com/jsyn/unitgen/SawtoothOscillatorDPW.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -20,7 +20,7 @@ package com.jsyn.unitgen;
  * Sawtooth DPW oscillator (a sawtooth with reduced aliasing).
  * Based on a paper by Antti Huovilainen and Vesa Valimaki:
  * http://www.scribd.com/doc/33863143/New-Approaches-to-Digital-Subtractive-Synthesis
- * 
+ *
  * @author Phil Burk and Lisa Tolentino (C) 2009 Mobileer Inc
  */
 public class SawtoothOscillatorDPW extends UnitOscillator {
diff --git a/src/com/jsyn/unitgen/SquareOscillatorBL.java b/src/com/jsyn/unitgen/SquareOscillatorBL.java
index cfe8541..cb9e141 100644
--- a/src/com/jsyn/unitgen/SquareOscillatorBL.java
+++ b/src/com/jsyn/unitgen/SquareOscillatorBL.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -21,7 +21,7 @@ import com.jsyn.engine.MultiTable;
 /**
  * Band-limited square wave oscillator. This requires more CPU than a SquareOscillator but is less
  * noisy at high frequencies.
- * 
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc
  */
 public class SquareOscillatorBL extends SawtoothOscillatorBL {
@@ -32,8 +32,9 @@ public class SquareOscillatorBL extends SawtoothOscillatorBL {
 
         /* Generate second sawtooth so we can add them together. */
         double phase2 = currentPhase + 1.0; /* 180 degrees out of phase. */
-        if (phase2 >= 1.0)
+        if (phase2 >= 1.0) {
             phase2 -= 2.0;
+        }
         double val2 = multiTable.calculateSawtooth(phase2, positivePhaseIncrement, flevel);
 
         /*
diff --git a/src/com/jsyn/unitgen/TunableFilter.java b/src/com/jsyn/unitgen/TunableFilter.java
index 1724ec1..31f6631 100644
--- a/src/com/jsyn/unitgen/TunableFilter.java
+++ b/src/com/jsyn/unitgen/TunableFilter.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -15,7 +15,7 @@
  */
 /**
  * Aug 26, 2009
- * com.jsyn.engine.units.TunableFilter.java 
+ * com.jsyn.engine.units.TunableFilter.java
  */
 
 package com.jsyn.unitgen;
@@ -24,13 +24,13 @@ import com.jsyn.ports.UnitInputPort;
 
 /**
  * A UnitFilter with a frequency port.
- * 
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc Translated from 'C' to Java by Lisa
  *         Tolenti.
  */
 public abstract class TunableFilter extends UnitFilter {
 
-    private static final double DEFAULT_FREQUENCY = 400;
+    static final double DEFAULT_FREQUENCY = 400;
     public UnitInputPort frequency;
 
     public TunableFilter() {
diff --git a/src/com/jsyn/unitgen/UnitGenerator.java b/src/com/jsyn/unitgen/UnitGenerator.java
index a9a7459..f8278ae 100644
--- a/src/com/jsyn/unitgen/UnitGenerator.java
+++ b/src/com/jsyn/unitgen/UnitGenerator.java
@@ -36,6 +36,20 @@ import com.softsynth.shared.time.TimeStamp;
  */
 public abstract class UnitGenerator {
     protected static final double VERY_SMALL_FLOAT = 1.0e-26;
+
+    // Some common port names.
+    public static final String PORT_NAME_INPUT = "Input";
+    public static final String PORT_NAME_OUTPUT = "Output";
+    public static final String PORT_NAME_PHASE = "Phase";
+    public static final String PORT_NAME_FREQUENCY = "Frequency";
+    public static final String PORT_NAME_FREQUENCY_SCALER = "FreqScaler";
+    public static final String PORT_NAME_AMPLITUDE = "Amplitude";
+    public static final String PORT_NAME_PAN = "Pan";
+    public static final String PORT_NAME_TIME = "Time";
+    public static final String PORT_NAME_CUTOFF = "Cutoff";
+    public static final String PORT_NAME_PRESSURE = "Pressure";
+    public static final String PORT_NAME_TIMBRE = "Timbre";
+
     public static final double FALSE = 0.0;
     public static final double TRUE = 1.0;
     protected SynthesisEngine synthesisEngine;
@@ -75,6 +89,11 @@ public abstract class UnitGenerator {
         addPort(port);
     }
 
+    /**
+     * Case-insensitive search for a port by name.
+     * @param portName
+     * @return matching port or null
+     */
     public UnitPort getPortByName(String portName) {
         return ports.get(portName.toLowerCase());
     }
@@ -141,8 +160,7 @@ public abstract class UnitGenerator {
         if (halfLife < (2.0 * getFramePeriod())) {
             return 1.0;
         } else {
-            // Strangely enough, this code is valid for both PeakFollower
-            // and AsymptoticRamp.
+            // Oddly enough, this code is valid for both PeakFollower and AsymptoticRamp.
             return 1.0 - Math.pow(0.5, 1.0 / (halfLife * getSynthesisEngine().getFrameRate()));
         }
     }
@@ -150,10 +168,11 @@ public abstract class UnitGenerator {
     protected double incrementWrapPhase(double currentPhase, double phaseIncrement) {
         currentPhase += phaseIncrement;
 
-        if (currentPhase >= 1.0)
+        if (currentPhase >= 1.0) {
             currentPhase -= 2.0;
-        else if (currentPhase < -1.0)
+        } else if (currentPhase < -1.0) {
             currentPhase += 2.0;
+        }
         return currentPhase;
     }
 
@@ -285,6 +304,11 @@ public abstract class UnitGenerator {
         getSynthesisEngine().stopUnit(this, timeStamp);
     }
 
+    /**
+     * @deprecated ignored, frameRate comes from the SynthesisEngine
+     * @param rate
+     */
+    @Deprecated
     public void setFrameRate(int rate) {
         this.frameRate = rate;
         this.framePeriod = 1.0 / rate;
diff --git a/src/com/jsyn/unitgen/UnitOscillator.java b/src/com/jsyn/unitgen/UnitOscillator.java
index 4c02f09..5d4c6fa 100644
--- a/src/com/jsyn/unitgen/UnitOscillator.java
+++ b/src/com/jsyn/unitgen/UnitOscillator.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -23,7 +23,7 @@ import com.softsynth.shared.time.TimeStamp;
 
 /**
  * Base class for all oscillators.
- * 
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc
  */
 public abstract class UnitOscillator extends UnitGenerator implements UnitVoice {
@@ -34,15 +34,15 @@ public abstract class UnitOscillator extends UnitGenerator implements UnitVoice
     public UnitOutputPort output;
 
     public static final double DEFAULT_FREQUENCY = 440.0;
-    public static final double DEFAULT_AMPLITUDE = 0x7FFF / (double) 0x8000;
+    public static final double DEFAULT_AMPLITUDE = 1.0;
 
     /* Define Unit Ports used by connect() and set(). */
     public UnitOscillator() {
-        addPort(frequency = new UnitInputPort("Frequency"));
+        addPort(frequency = new UnitInputPort(PORT_NAME_FREQUENCY));
         frequency.setup(40.0, DEFAULT_FREQUENCY, 8000.0);
-        addPort(amplitude = new UnitInputPort("Amplitude", DEFAULT_AMPLITUDE));
-        addPort(phase = new UnitVariablePort("Phase"));
-        addPort(output = new UnitOutputPort("Output"));
+        addPort(amplitude = new UnitInputPort(PORT_NAME_AMPLITUDE, DEFAULT_AMPLITUDE));
+        addPort(phase = new UnitVariablePort(PORT_NAME_PHASE));
+        addPort(output = new UnitOutputPort(PORT_NAME_OUTPUT));
     }
 
     /**
diff --git a/src/com/jsyn/util/MultiChannelSynthesizer.java b/src/com/jsyn/util/MultiChannelSynthesizer.java
new file mode 100644
index 0000000..c2d0e86
--- /dev/null
+++ b/src/com/jsyn/util/MultiChannelSynthesizer.java
@@ -0,0 +1,303 @@
+/*
+ * Copyright 2016 Phil Burk, Mobileer Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jsyn.util;
+
+import com.jsyn.Synthesizer;
+import com.jsyn.engine.SynthesisEngine;
+import com.jsyn.midi.MidiConstants;
+import com.jsyn.ports.UnitInputPort;
+import com.jsyn.ports.UnitOutputPort;
+import com.jsyn.unitgen.ExponentialRamp;
+import com.jsyn.unitgen.Multiply;
+import com.jsyn.unitgen.Pan;
+import com.jsyn.unitgen.LinearRamp;
+import com.jsyn.unitgen.PowerOfTwo;
+import com.jsyn.unitgen.SineOscillator;
+import com.jsyn.unitgen.TwoInDualOut;
+import com.jsyn.unitgen.UnitGenerator;
+import com.jsyn.unitgen.UnitOscillator;
+import com.jsyn.unitgen.UnitVoice;
+import com.softsynth.math.AudioMath;
+import com.softsynth.shared.time.TimeStamp;
+
+/**
+ * General purpose synthesizer with "channels"
+ * that could be used to implement a MIDI synthesizer.
+ *
+ * Each channel has:
+ * <pre><code>
+ * lfo -> pitchToLinear -> [VOICES] -> volume* -> panner
+ * bend --/
+ * </code></pre>
+ *
+ * Note: this class is experimental and subject to change.
+ *
+ * @author Phil Burk (C) 2016 Mobileer Inc
+ */
+public class MultiChannelSynthesizer {
+    private Synthesizer synth;
+    private TwoInDualOut outputUnit;
+    private ChannelContext[] channels;
+
+    private class ChannelContext {
+        private VoiceDescription voiceDescription;
+        private UnitVoice[] voices;
+        private VoiceAllocator allocator;
+        private UnitOscillator lfo;
+        private PowerOfTwo pitchToLinear;
+        private LinearRamp timbreRamp;
+        private LinearRamp pressureRamp;
+        private ExponentialRamp volumeRamp;
+        private Multiply volumeMultiplier;
+        private Pan panner;
+        private double vibratoRate = 5.0;
+        private double bendRangeOctaves = 24.0 / 12.0;
+//        private double bendRangeOctaves = 0.0 / 12.0;
+        private int presetIndex;
+
+        void setup(int numVoices, VoiceDescription voiceDescription) {
+            this.voiceDescription = voiceDescription;
+            synth.add(pitchToLinear = new PowerOfTwo());
+            synth.add(lfo = new SineOscillator()); // TODO use a MorphingOscillator or switch
+                                                   // between S&H etc.
+            // Use a ramp to smooth out the timbre changes.
+            // This helps reduce pops from changing filter cutoff too abruptly.
+            synth.add(timbreRamp = new LinearRamp());
+            timbreRamp.time.set(0.02);
+            synth.add(pressureRamp = new LinearRamp());
+            pressureRamp.time.set(0.02);
+            synth.add(volumeRamp = new ExponentialRamp());
+            volumeRamp.input.set(1.0);
+            volumeRamp.time.set(0.02);
+            synth.add(volumeMultiplier = new Multiply());
+            synth.add(panner = new Pan());
+
+            pitchToLinear.input.setValueAdded(true); // so we can sum pitch bend
+            lfo.output.connect(pitchToLinear.input);
+            lfo.amplitude.set(0.0);
+            lfo.frequency.set(vibratoRate);
+
+            voices = new UnitVoice[numVoices];
+            for (int i = 0; i < numVoices; i++) {
+                UnitVoice voice = voiceDescription.createUnitVoice();
+                UnitGenerator ugen = voice.getUnitGenerator();
+                synth.add(ugen);
+
+                // Hook up some channel controllers to standard ports on the voice.
+                UnitInputPort freqMod = (UnitInputPort) ugen
+                        .getPortByName(UnitGenerator.PORT_NAME_FREQUENCY_SCALER);
+                if (freqMod != null) {
+                    pitchToLinear.output.connect(freqMod);
+                }
+                UnitInputPort timbrePort = (UnitInputPort) ugen
+                        .getPortByName(UnitGenerator.PORT_NAME_TIMBRE);
+                if (timbrePort != null) {
+                    timbreRamp.output.connect(timbrePort);
+                    timbreRamp.input.setup(timbrePort);
+                }
+                UnitInputPort pressurePort = (UnitInputPort) ugen
+                        .getPortByName(UnitGenerator.PORT_NAME_PRESSURE);
+                if (pressurePort != null) {
+                    pressureRamp.output.connect(pressurePort);
+                    pressureRamp.input.setup(pressurePort);
+                }
+                voice.getOutput().connect(volumeMultiplier.inputA); // mono mix all the voices
+                voices[i] = voice;
+            }
+
+            volumeRamp.output.connect(volumeMultiplier.inputB);
+            volumeMultiplier.output.connect(panner.input);
+            panner.output.connect(0, outputUnit.inputA, 0); // Use MultiPassthrough
+            panner.output.connect(1, outputUnit.inputB, 0);
+
+            allocator = new VoiceAllocator(voices);
+        }
+
+        void programChange(int program) {
+            int programWrapped = program % voiceDescription.getPresetCount();
+            String name = voiceDescription.getPresetNames()[programWrapped];
+            System.out.println("Preset[" + program + "] = " + name);
+            presetIndex = programWrapped;
+        }
+
+        void noteOff(int noteNumber, int velocity) {
+            allocator.noteOff(noteNumber, synth.createTimeStamp());
+        }
+
+        void noteOn(int noteNumber, int velocity) {
+            double frequency = AudioMath.pitchToFrequency(noteNumber);
+            double amplitude = velocity / (4 * 128.0);
+            TimeStamp timeStamp = synth.createTimeStamp();
+            allocator.usePreset(presetIndex, timeStamp);
+            // System.out.println("noteOn(noteNumber) -> " + frequency + " Hz");
+            allocator.noteOn(noteNumber, frequency, amplitude, timeStamp);
+        }
+
+        public void setPitchBend(double offset) {
+            pitchToLinear.input.set(bendRangeOctaves * offset);
+        }
+
+        public void setBendRange(double semitones) {
+            bendRangeOctaves = semitones / 12.0;
+        }
+
+        public void setVibratoDepth(double semitones) {
+            lfo.amplitude.set(semitones);
+        }
+
+        public void setVolume(double volume) {
+            double min = SynthesisEngine.DB96;
+            double max = 1.0;
+            double ratio = max / min;
+            double value = min * Math.pow(ratio, volume);
+            volumeRamp.input.set(value);
+        }
+
+        public void setPan(double pan) {
+            panner.pan.set(pan);
+        }
+
+        /*
+         * @param timbre normalized 0 to 1
+         */
+        public void setTimbre(double timbre) {
+            double min = timbreRamp.input.getMinimum();
+            double max = timbreRamp.input.getMaximum();
+            double value = min + (timbre * (max - min));
+            timbreRamp.input.set(value);
+        }
+
+        /*
+         * @param pressure normalized 0 to 1
+         */
+        public void setPressure(double pressure) {
+            double min = pressureRamp.input.getMinimum();
+            double max = pressureRamp.input.getMaximum();
+            double ratio = max / min;
+            double value = min * Math.pow(ratio, pressure);
+            pressureRamp.input.set(value);
+        }
+    }
+
+    /**
+     * Construct a synthesizer with a maximum of 16 channels like MIDI.
+     */
+    public MultiChannelSynthesizer() {
+        this(MidiConstants.MAX_CHANNELS);
+    }
+
+
+    public MultiChannelSynthesizer(int maxChannels) {
+        channels = new ChannelContext[maxChannels];
+        for (int i = 0; i < channels.length; i++) {
+            channels[i] = new ChannelContext();
+        }
+    }
+
+    /**
+     * Specify a VoiceDescription to use with multiple channels.
+     *
+     * @param synth
+     * @param startChannel channel index is zero based
+     * @param numChannels
+     * @param voicesPerChannel
+     * @param voiceDescription
+     */
+    public void setup(Synthesizer synth, int startChannel, int numChannels, int voicesPerChannel,
+            VoiceDescription voiceDescription) {
+        this.synth = synth;
+        if (outputUnit == null) {
+            synth.add(outputUnit = new TwoInDualOut());
+        }
+        for (int i = 0; i < numChannels; i++) {
+            channels[startChannel + i].setup(voicesPerChannel, voiceDescription);
+        }
+    }
+
+    public void programChange(int channel, int program) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.programChange(program);
+    }
+
+    public void noteOff(int channel, int noteNumber, int velocity) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.noteOff(noteNumber, velocity);
+    }
+
+    public void noteOn(int channel, int noteNumber, int velocity) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.noteOn(noteNumber, velocity);
+    }
+
+    /**
+     * Set a pitch offset that will be scaled by the range for the channel.
+     *
+     * @param channel
+     * @param offset ranges from -1.0 to +1.0
+     */
+    public void setPitchBend(int channel, double offset) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setPitchBend(offset);
+    }
+
+    public void setBendRange(int channel, double semitones) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setBendRange(semitones);
+    }
+
+    public void setPressure(int channel, double pressure) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setPressure(pressure);
+    }
+
+    public void setVibratoDepth(int channel, double semitones) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setVibratoDepth(semitones);
+    }
+
+    public void setTimbre(int channel, double timbre) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setTimbre(timbre);
+    }
+
+    /**
+     * Set volume for entire channel.
+     *
+     * @param channel
+     * @param volume normalized between 0.0 and 1.0
+     */
+    public void setVolume(int channel, double volume) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setVolume(volume);
+    }
+
+    /**
+     * Pan from left to right.
+     *
+     * @param channel
+     * @param offset ranges from -1.0 to +1.0
+     */
+    public void setPan(int channel, double pan) {
+        ChannelContext channelContext = channels[channel];
+        channelContext.setPan(pan);
+    }
+
+    public UnitOutputPort getOutput() {
+        return outputUnit.output;
+    }
+
+}
diff --git a/src/com/jsyn/util/PolyphonicInstrument.java b/src/com/jsyn/util/PolyphonicInstrument.java
index 8501554..2cba78f 100644
--- a/src/com/jsyn/util/PolyphonicInstrument.java
+++ b/src/com/jsyn/util/PolyphonicInstrument.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -29,7 +29,7 @@ import com.softsynth.shared.time.TimeStamp;
 
 /**
  * The API for this class is likely to change. Please comment on its usefulness.
- * 
+ *
  * @author Phil Burk (C) 2011 Mobileer Inc
  */
 
@@ -56,6 +56,7 @@ public class PolyphonicInstrument extends Circuit implements UnitSource, Instrum
 
         addPort(amplitude = mixer.inputB, "Amplitude");
         amplitude.setup(0.0001, 0.4, 2.0);
+        exportAllInputPorts();
     }
 
     /**
@@ -81,11 +82,11 @@ public class PolyphonicInstrument extends Circuit implements UnitSource, Instrum
     /**
      * Create a UnitInputPort for the circuit that is connected to the named port on each voice
      * through a PassThrough unit. This allows you to control all of the voices at once.
-     * 
+     *
      * @param portName
      * @see exportAllInputPorts
      */
-    public void exportNamedInputPort(String portName) {
+    void exportNamedInputPort(String portName) {
         UnitInputPort voicePort = null;
         PassThrough fanout = new PassThrough();
         for (UnitVoice voice : voices) {
@@ -103,7 +104,6 @@ public class PolyphonicInstrument extends Circuit implements UnitSource, Instrum
         return mixer.output;
     }
 
-    // FIXME - no timestamp on UnitVoice
     @Override
     public void usePreset(int presetIndex) {
         usePreset(presetIndex, getSynthesisEngine().createTimeStamp());
diff --git a/src/com/jsyn/util/VoiceAllocator.java b/src/com/jsyn/util/VoiceAllocator.java
index af37b91..f20f7a5 100644
--- a/src/com/jsyn/util/VoiceAllocator.java
+++ b/src/com/jsyn/util/VoiceAllocator.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -25,7 +25,7 @@ import com.softsynth.shared.time.TimeStamp;
  * Allocate voices based on an integer tag. The tag could, for example, be a MIDI note number. Or a
  * tag could be an int that always increments. Use the same tag to refer to a voice for noteOn() and
  * noteOff(). If no new voices are available then a voice in use will be stolen.
- * 
+ *
  * @author Phil Burk (C) 2011 Mobileer Inc
  */
 public class VoiceAllocator implements Instrument {
@@ -33,12 +33,13 @@ public class VoiceAllocator implements Instrument {
     private VoiceTracker[] trackers;
     private long tick;
     private Synthesizer synthesizer;
-    private int presetIndex = -1;
+    private static final int UNASSIGNED_PRESET = -1;
+    private int mPresetIndex = UNASSIGNED_PRESET;
 
     /**
      * Create an allocator for the array of UnitVoices. The array must be full of instantiated
      * UnitVoices that are connected to some kind of mixer.
-     * 
+     *
      * @param voices
      */
     public VoiceAllocator(UnitVoice[] voices) {
@@ -60,7 +61,7 @@ public class VoiceAllocator implements Instrument {
     private class VoiceTracker {
         UnitVoice voice;
         int tag = -1;
-        int presetIndex = -1;
+        int presetIndex = UNASSIGNED_PRESET;
         long when;
         boolean on;
 
@@ -121,7 +122,7 @@ public class VoiceAllocator implements Instrument {
      * that tag. Next it will pick the oldest voice that is off. Next it will pick the oldest voice
      * that is on. If you are using timestamps to play the voice in the future then you should use
      * the noteOn() noteOff() and setPort() methods.
-     * 
+     *
      * @param tag
      * @return Voice that is most available.
      */
@@ -185,14 +186,35 @@ public class VoiceAllocator implements Instrument {
             @Override
             public void run() {
                 VoiceTracker voiceTracker = allocateTracker(tag);
-                if (presetIndex != voiceTracker.presetIndex) {
-                    voiceTracker.voice.usePreset(presetIndex);
+                if (voiceTracker.presetIndex != mPresetIndex) {
+                    voiceTracker.voice.usePreset(mPresetIndex);
+                    voiceTracker.presetIndex = mPresetIndex;
                 }
                 voiceTracker.voice.noteOn(frequency, amplitude, getSynthesizer().createTimeStamp());
             }
         });
     }
 
+    /**
+     * Play a note on the voice and associate it with the given tag. if needed a new voice will be
+     * allocated and an old voice may be turned off.
+     * Apply an operation to the voice.
+     */
+    public void noteOn(final int tag,
+            final double frequency,
+            final double amplitude,
+            final VoiceOperation operation,
+            TimeStamp timeStamp) {
+        getSynthesizer().scheduleCommand(timeStamp, new ScheduledCommand() {
+            @Override
+            public void run() {
+                VoiceTracker voiceTracker = allocateTracker(tag);
+                operation.operate(voiceTracker.voice);
+                voiceTracker.voice.noteOn(frequency, amplitude, getSynthesizer().createTimeStamp());
+            }
+        });
+    }
+
     /** Turn off the voice associated with the given tag if allocated. */
     @Override
     public void noteOff(final int tag, TimeStamp timeStamp) {
@@ -228,9 +250,7 @@ public class VoiceAllocator implements Instrument {
         getSynthesizer().scheduleCommand(timeStamp, new ScheduledCommand() {
             @Override
             public void run() {
-                for (VoiceTracker tracker : trackers) {
-                    tracker.voice.usePreset(presetIndex);
-                }
+                mPresetIndex = presetIndex;
             }
         });
     }
diff --git a/src/com/jsyn/util/VoiceOperation.java b/src/com/jsyn/util/VoiceOperation.java
new file mode 100644
index 0000000..cd3b48e
--- /dev/null
+++ b/src/com/jsyn/util/VoiceOperation.java
@@ -0,0 +1,7 @@
+package com.jsyn.util;
+
+import com.jsyn.unitgen.UnitVoice;
+
+public interface VoiceOperation {
+    public void operate(UnitVoice voice);
+}