diff --git a/Source/PluginGui.cpp b/Source/PluginGui.cpp
index d96caa0..d82703f 100644
--- a/Source/PluginGui.cpp
+++ b/Source/PluginGui.cpp
@@ -797,6 +797,11 @@ PluginGui::PluginGui (JuceOplvstiAudioProcessor* ownerFilter)
     keyscaleAttenuationComboBox->addItem ("-6.0", 4);
     keyscaleAttenuationComboBox->addListener (this);
 
+    addAndMakeVisible (groupComponent4 = new GroupComponent ("new group",
+                                                             "Channels"));
+    groupComponent4->setTextLabelPosition (Justification::centredLeft);
+    groupComponent4->setColour (GroupComponent::outlineColourId, Colour (0xff007f00));
+    groupComponent4->setColour (GroupComponent::textColourId, Colour (0xff007f00));
 
     //[UserPreSize]
 	frequencyComboBox->setColour (ComboBox::textColourId, Colour (COLOUR_MID));
@@ -908,13 +913,29 @@ PluginGui::PluginGui (JuceOplvstiAudioProcessor* ownerFilter)
 	vibratoButton2->setColour(TextButton::buttonColourId, Colour(COLOUR_MID));
 	keyscaleEnvButton2->setColour(TextButton::buttonColourId, Colour(COLOUR_MID));
 	sustainButton2->setColour(TextButton::buttonColourId, Colour(COLOUR_MID));
+
+	for (int i = 0; i < channels.size(); ++i)
+	{
+		ImageButton *channel=new ImageButton("new button");
+
+		addAndMakeVisible(channel);
+		channel->addListener(this);
+
+		channel->setImages(false, true, true,
+			ImageCache::getFromMemory(channeloff_png, channeloff_pngSize), 1.000f, Colour(0x00000000),
+			Image(), 1.000f, Colour(0x00000000),
+			ImageCache::getFromMemory(channelon_png, channelon_pngSize), 1.000f, Colour(0x00000000));
+
+		channels[i]=channel;
+	}
     //[/UserPreSize]
 
-    setSize (440, 810);
+    setSize (440, 874);
 
 
     //[Constructor] You can add your own custom stuff here..
 	processor = ownerFilter;
+	startTimer(1000/30);
     //[/Constructor]
 }
 
@@ -998,6 +1019,7 @@ PluginGui::~PluginGui()
     dbLabel4 = nullptr;
     keyscaleAttenuationComboBox2 = nullptr;
     keyscaleAttenuationComboBox = nullptr;
+    groupComponent4 = nullptr;
 
 
     //[Destructor]. You can add your own custom destruction code here..
@@ -1093,7 +1115,10 @@ void PluginGui::resized()
     dbLabel4->setBounds (336, 440, 72, 16);
     keyscaleAttenuationComboBox2->setBounds (264, 432, 72, 24);
     keyscaleAttenuationComboBox->setBounds (264, 88, 72, 24);
+    groupComponent4->setBounds (16, 800, 408, 64);
     //[UserResized] Add your own custom resize handling here..
+	for (int i = 0; i < channels.size(); ++i)
+		channels[i]->setBounds(32+24*i+4, 824+4, 16, 16);
     //[/UserResized]
 }
 
@@ -1431,6 +1456,12 @@ void PluginGui::buttonClicked (Button* buttonThatWasClicked)
 			processor->loadInstrumentFromFile(files[0]);
 		}
     }
+
+	void PluginGui::timerCallback()
+	{
+		for (int i = 0; i < Hiopl::CHANNELS; ++i)
+			channels[i]->setState(processor->isChannelActive(i+1) ? Button::buttonDown : Button::buttonNormal);
+	}
 //[/MiscUserCode]
 
 
@@ -1444,10 +1475,10 @@ void PluginGui::buttonClicked (Button* buttonThatWasClicked)
 BEGIN_JUCER_METADATA
 
 <JUCER_COMPONENT documentType="Component" className="PluginGui" componentName=""
-                 parentClasses="public AudioProcessorEditor, public FileDragAndDropTarget, public DragAndDropContainer"
+                 parentClasses="public AudioProcessorEditor, public FileDragAndDropTarget, public DragAndDropContainer, public Timer"
                  constructorParams="JuceOplvstiAudioProcessor* ownerFilter" variableInitialisers=" AudioProcessorEditor (ownerFilter)"
                  snapPixels="8" snapActive="1" snapShown="1" overlayOpacity="0.33"
-                 fixedSize="0" initialWidth="440" initialHeight="810">
+                 fixedSize="0" initialWidth="440" initialHeight="874">
   <BACKGROUND backgroundColour="ff000000"/>
   <GROUPCOMPONENT name="new group" id="d2c7c07bf2d78c30" memberName="groupComponent"
                   virtualName="" explicitFocusOrder="0" pos="16 8 408 336" outlinecol="ff007f00"
@@ -1829,6 +1860,9 @@ BEGIN_JUCER_METADATA
             virtualName="" explicitFocusOrder="0" pos="264 88 72 24" editable="0"
             layout="33" items="-0.0&#10;-3.0&#10;-1.5&#10;-6.0" textWhenNonSelected=""
             textWhenNoItems="(no choices)"/>
+  <GROUPCOMPONENT name="new group" id="52f9803abb342980" memberName="groupComponent4"
+                  virtualName="" explicitFocusOrder="0" pos="16 800 408 64" outlinecol="ff007f00"
+                  textcol="ff007f00" title="Channels" textpos="33"/>
 </JUCER_COMPONENT>
 
 END_JUCER_METADATA
@@ -1910,6 +1944,30 @@ static const unsigned char resource_PluginGui_logarithmic_saw_png[] = { 137,80,7
 const char* PluginGui::logarithmic_saw_png = (const char*) resource_PluginGui_logarithmic_saw_png;
 const int PluginGui::logarithmic_saw_pngSize = 206;
 
+// JUCER_RESOURCE: channeloff_png, 414, "../img/channeloff.png"
+static const unsigned char resource_PluginGui_channeloff_png[] = { 137,80,78,71,13,10,26,10,0,0,0,13,73,72,68,82,0,0,0,16,0,0,0,16,8,6,0,0,0,31,243,255,97,0,0,0,6,98,75,71,68,0,0,0,0,0,0,249,67,187,127,
+0,0,0,9,112,72,89,115,0,0,11,19,0,0,11,19,1,0,154,156,24,0,0,0,7,116,73,77,69,7,222,8,25,20,6,56,156,246,144,159,0,0,0,29,105,84,88,116,67,111,109,109,101,110,116,0,0,0,0,0,67,114,101,97,116,101,100,32,
+119,105,116,104,32,71,73,77,80,100,46,101,7,0,0,1,2,73,68,65,84,56,203,165,211,61,78,66,65,20,5,224,143,193,82,119,224,62,104,40,166,196,194,202,10,66,65,137,149,75,120,121,193,21,216,104,108,164,32,178,
+128,183,1,94,66,67,66,172,172,140,27,176,178,192,202,70,139,55,26,2,138,2,39,153,102,230,220,159,185,231,220,154,85,100,14,113,138,46,154,233,118,138,17,10,185,183,101,122,88,9,110,99,129,11,20,104,164,
+83,164,187,69,226,252,128,204,64,230,67,166,239,55,100,250,137,51,176,86,185,122,104,249,11,153,86,226,182,161,150,254,188,192,185,220,141,255,160,234,242,26,71,117,209,25,142,229,27,90,95,69,105,46,58,
+193,107,72,211,30,218,30,67,116,67,146,106,178,67,130,9,154,193,158,8,201,36,113,135,216,136,105,72,14,235,237,144,160,135,81,248,118,92,182,133,10,21,183,129,162,174,244,46,122,194,157,104,166,244,252,
+167,145,24,163,35,247,80,79,186,62,138,14,112,43,122,81,154,111,168,60,198,165,220,85,229,196,245,101,186,199,44,233,60,89,26,88,47,181,221,145,27,127,133,212,246,93,231,79,44,229,73,181,37,137,229,213,
+0,0,0,0,73,69,78,68,174,66,96,130,0,0};
+
+const char* PluginGui::channeloff_png = (const char*) resource_PluginGui_channeloff_png;
+const int PluginGui::channeloff_pngSize = 414;
+
+// JUCER_RESOURCE: channelon_png, 326, "../img/channelon.png"
+static const unsigned char resource_PluginGui_channelon_png[] = { 137,80,78,71,13,10,26,10,0,0,0,13,73,72,68,82,0,0,0,16,0,0,0,16,8,6,0,0,0,31,243,255,97,0,0,0,6,98,75,71,68,0,0,0,0,0,0,249,67,187,127,
+0,0,0,9,112,72,89,115,0,0,11,19,0,0,11,19,1,0,154,156,24,0,0,0,7,116,73,77,69,7,222,8,25,20,6,39,17,254,157,106,0,0,0,29,105,84,88,116,67,111,109,109,101,110,116,0,0,0,0,0,67,114,101,97,116,101,100,32,
+119,105,116,104,32,71,73,77,80,100,46,101,7,0,0,0,170,73,68,65,84,56,203,173,147,177,13,194,48,16,69,159,143,148,176,81,20,101,129,84,84,68,217,5,89,176,0,204,16,193,0,30,0,69,202,8,169,88,131,12,64,145,
+139,176,82,64,116,230,117,182,252,206,242,249,159,99,201,145,45,80,1,13,144,235,110,15,180,64,192,51,198,199,221,66,62,0,55,190,83,227,185,207,139,77,36,159,128,11,191,217,83,146,209,241,248,20,152,110,
+94,35,207,20,148,60,233,24,156,190,249,133,141,157,104,195,172,84,162,221,182,210,72,244,85,22,114,33,17,209,144,88,233,69,19,102,165,21,32,36,20,8,162,217,174,13,114,141,103,156,146,216,49,80,146,1,197,
+74,249,140,231,250,151,97,114,169,227,252,6,230,208,38,246,228,75,209,233,0,0,0,0,73,69,78,68,174,66,96,130,0,0};
+
+const char* PluginGui::channelon_png = (const char*) resource_PluginGui_channelon_png;
+const int PluginGui::channelon_pngSize = 326;
+
 
 //[EndFile] You can add extra defines here...
 //[/EndFile]
diff --git a/Source/PluginGui.h b/Source/PluginGui.h
index 6d7cc25..f53c958 100644
--- a/Source/PluginGui.h
+++ b/Source/PluginGui.h
@@ -21,6 +21,7 @@
 #define __JUCE_HEADER_450C07F5C14097B8__
 
 //[Headers]     -- You can add your own extra header files here --
+#include <array>
 #include "JuceHeader.h"
 #include "PluginProcessor.h"
 //[/Headers]
@@ -36,6 +37,7 @@
 class PluginGui  : public AudioProcessorEditor,
                    public FileDragAndDropTarget,
                    public DragAndDropContainer,
+                   public Timer,
                    public ComboBoxListener,
                    public SliderListener,
                    public ButtonListener
@@ -53,6 +55,7 @@ public:
     void fileDragMove (const StringArray& files, int x, int y);
     void fileDragExit (const StringArray& files);
     void filesDropped (const StringArray& files, int x, int y);
+	void timerCallback();
     //[/UserMethods]
 
     void paint (Graphics& g);
@@ -78,12 +81,17 @@ public:
     static const int square_pngSize;
     static const char* logarithmic_saw_png;
     static const int logarithmic_saw_pngSize;
+    static const char* channeloff_png;
+    static const int channeloff_pngSize;
+    static const char* channelon_png;
+    static const int channelon_pngSize;
 
 
 private:
     //[UserVariables]   -- You can add your own custom variables in this section.
 	static const uint32 COLOUR_MID = 0xff007f00;
 	JuceOplvstiAudioProcessor* processor;
+	std::array<ScopedPointer<ImageButton>, Hiopl::CHANNELS> channels;
     //[/UserVariables]
 
     //==============================================================================
@@ -162,6 +170,7 @@ private:
     ScopedPointer<Label> dbLabel4;
     ScopedPointer<ComboBox> keyscaleAttenuationComboBox2;
     ScopedPointer<ComboBox> keyscaleAttenuationComboBox;
+    ScopedPointer<GroupComponent> groupComponent4;
 
 
     //==============================================================================
diff --git a/Source/PluginProcessor.cpp b/Source/PluginProcessor.cpp
index 91f5b7e..a3146c7 100644
--- a/Source/PluginProcessor.cpp
+++ b/Source/PluginProcessor.cpp
@@ -122,6 +122,9 @@ JuceOplvstiAudioProcessor::JuceOplvstiAudioProcessor()
 		active_notes[i] = NO_NOTE;
 	}
 	currentScaledBend = 1.0f;
+
+	for (int i = 1; i <= Hiopl::CHANNELS; ++i)
+		available_channels.push_back(i);
 }
 
 void JuceOplvstiAudioProcessor::initPrograms()
@@ -381,7 +384,7 @@ void JuceOplvstiAudioProcessor::applyPitchBend()
 
 JuceOplvstiAudioProcessor::~JuceOplvstiAudioProcessor()
 {
-	for (int i = 0; i < params.size(); ++i)
+	for (int i=0; i < params.size(); ++i)
 		delete params[i];
 }
 
@@ -648,10 +651,22 @@ void JuceOplvstiAudioProcessor::processBlock (AudioSampleBuffer& buffer, MidiBuf
 			//the beginning of the current buffer
 			int n = midi_message.getNoteNumber();
 			float noteHz = (float)MidiMessage::getMidiNoteInHertz(n);
-			int ch = 1;
-			while (ch <= Hiopl::CHANNELS && NO_NOTE != active_notes[ch]) {
-				ch += 1;
+			int ch;
+
+			if (!available_channels.empty())
+			{
+				ch = available_channels.front();
+				available_channels.pop_front();
 			}
+			else
+			{
+				ch = used_channels.back(); // steal earliest/longest running active channel if out of free channels
+				used_channels.pop_back();
+				Opl->KeyOff(ch);
+			}
+
+			used_channels.push_front(ch);
+
 			switch (getEnumParameter("Carrier Velocity Sensitivity")) {
 				case 0:
 					Opl->SetAttenuation(ch, 2, getEnumParameter("Carrier Attenuation"));
@@ -684,9 +699,23 @@ void JuceOplvstiAudioProcessor::processBlock (AudioSampleBuffer& buffer, MidiBuf
 			while (ch <= Hiopl::CHANNELS && n != active_notes[ch]) {
 				ch += 1;
 			}
+			if (ch <= Hiopl::CHANNELS)
+			{
+				for (auto i = used_channels.begin(); i != used_channels.end(); ++i)
+				{
+					if (*i == ch)
+					{
+						used_channels.erase(i);
+						available_channels.push_back(ch);
+
+						break;
+					}
+				}
+
 				Opl->KeyOff(ch);
 				active_notes[ch]=NO_NOTE;
 			}
+		}
 		else if (midi_message.isPitchWheel()) {
 			int bend = midi_message.getPitchWheelValue() - 0x2000;	// range -8192 to 8191
 			// 1.05946309436 == (2^(1/1200))^100 == 1 semitone == 100 cents
@@ -714,7 +743,7 @@ AudioProcessorEditor* JuceOplvstiAudioProcessor::createEditor()
 template<class T>
 void push(char *&cursor, T value)
 {
-	*reinterpret_cast<T *>(cursor) = value;
+	*reinterpret_cast<T *>(cursor)=value;
 	cursor+=sizeof(T);
 }
 
@@ -777,6 +806,13 @@ void JuceOplvstiAudioProcessor::setStateInformation (const void* data, int sizeI
 	}
 }
 
+// @param idx 1-based channel index
+// @note since this is just reading off pod, "safe" to access without a mutex by other threads such as GUI
+int JuceOplvstiAudioProcessor::isChannelActive(int idx) const
+{
+	return active_notes[idx] != NO_NOTE;
+}
+
 //==============================================================================
 // This creates new instances of the plugin..
 AudioProcessor* JUCE_CALLTYPE createPluginFilter()
diff --git a/Source/PluginProcessor.h b/Source/PluginProcessor.h
index c7a95b2..508586f 100644
--- a/Source/PluginProcessor.h
+++ b/Source/PluginProcessor.h
@@ -10,6 +10,7 @@
 #ifndef PLUGINPROCESSOR_H_INCLUDED
 #define PLUGINPROCESSOR_H_INCLUDED
 
+#include <deque>
 #include "../JuceLibraryCode/JuceHeader.h"
 #include "hiopl.h"
 #include "FloatParameter.h"
@@ -53,6 +54,8 @@ public:
 	void loadInstrumentFromFile(String filename);
 	void setParametersByRegister(int register_base, int op, uint8 value);
 
+	int isChannelActive(int idx) const;
+
 	void updateGuiIfPresent();
 
     const String getParameterName (int index);
@@ -90,6 +93,8 @@ private:
 	static const int NO_NOTE=-1;
 	static const int CURRENT_VERSION = 0x09720100; // OPL2 v01.00 magic
 	int active_notes[Hiopl::CHANNELS+1];	// keyed by channel
+	std::deque<int> available_channels;		// most recently freed at end
+	std::deque<int> used_channels;			// most recently used at end
 	float currentScaledBend;
 
     //==============================================================================
diff --git a/img/channeloff.png b/img/channeloff.png
new file mode 100644
index 0000000..f73544a
Binary files /dev/null and b/img/channeloff.png differ
diff --git a/img/channelon.png b/img/channelon.png
new file mode 100644
index 0000000..dcd0e58
Binary files /dev/null and b/img/channelon.png differ