diff --git a/images/apple/DHGR-BIGSHOW.PO b/images/apple/DHGR-BIGSHOW.PO
index 0f3b351..2c1c74a 100644
Binary files a/images/apple/DHGR-BIGSHOW.PO and b/images/apple/DHGR-BIGSHOW.PO differ
diff --git a/src/dhgr.tk/utils/dhgrrgb.pla b/src/dhgr.tk/utils/dhgrrgb.pla
index 6749c7c..5f4f88d 100644
--- a/src/dhgr.tk/utils/dhgrrgb.pla
+++ b/src/dhgr.tk/utils/dhgrrgb.pla
@@ -535,5 +535,5 @@ if ^arg
   fin
   return 0
 fin
-puts("Usage: DHGRRGB [-B#] [-E#] [-G#] [-T#] RGBFILE [DHGRFILE]\n")
+puts("Usage: DHGRRGB [-B#] -C#] [-E#] [-G#] [-M] [-T#] RGBFILE [DHGRFILE]\n")
 done
diff --git a/src/mockingboard/cvtmid.py b/src/mockingboard/cvtmid.py
index f50034f..087ae68 100755
--- a/src/mockingboard/cvtmid.py
+++ b/src/mockingboard/cvtmid.py
@@ -7,6 +7,7 @@ import mido
 optarg     = 1
 timescale  = 16.0 # Scale time to 16th of a second
 extperchan = 9    # Default to standard MIDI channel  10 for extra percussion
+channels = []
 if len(sys.argv) == 1:
     print('Usage:', sys.argv[0], '[-p extra_percussion_channel] [-t timescale] MIDI_file')
     sys.exit(0)
@@ -16,19 +17,24 @@ while optarg < (len(sys.argv) - 1):
         timescale = float(sys.argv[optarg + 1]) * 16.0
         optarg += 2
     if sys.argv[optarg] == '-p': # Add extra percussion channel
-        extperchan = int(sys.argv[optarg + 1]) - 1
+        extperchan = int(sys.argv[optarg + 1])
+        channels.append(extperchan)
         optarg += 2
+    if sys.argv[optarg][0] == '+': # Enable channel
+        channels.append(int(sys.argv[optarg][1]))
+        optarg += 1
 mid = mido.MidiFile(sys.argv[optarg])
 timeshift = timescale
-totaltime = 0
+#totaltime = 0.0
 eventtime = 0.0
 for msg in mid:
     eventtime += msg.time * timeshift
+    #totaltime += eventtime
+    deltatime = int(round(eventtime))
     #print '; time = ', msg.time
     if msg.type == 'note_on' or msg.type == 'note_off':
         #if eventtime > 0.0 and eventtime < 0.5:
         #    eventtime = 0.5
-        deltatime = int(round(eventtime))
         octave    = int(msg.note / 12 - 1)
         onote     = int(msg.note % 12)
         lrchan    = int(msg.channel & 1)
@@ -39,22 +45,22 @@ for msg in mid:
             vol = 0
         if octave < 0:
             octave = 0
-        totaltime += deltatime
-        if msg.channel == 9 or msg.channel == extperchan:
-            #
-            # Percussion
-            #
-            if vol > 0:
-                print('\t!BYTE\t${0:02X}, ${1:02X}, ${2:02X}\t; Percussion {3:d} Chan {4:d} Dur {5:d}'.format(deltatime, msg.note ^ 0x40, (lrchan << 7) | vol, msg.note, msg.channel + 1, vol))
-                if extperchan == 9: # Play percussion on both channels if no extended percussion
-                    print('\t!BYTE\t${0:02X}, ${1:02X}, ${2:02X}\t; Percussion {3:d} Chan {4:d} Dur {5:d}'.format(0, msg.note ^ 0x40, vol, msg.note, msg.channel + 1, vol))
+        if msg.channel in channels:
+            if msg.channel == 9 or msg.channel == extperchan:
+                #
+                # Percussion
+                #
+                if vol > 0:
+                    print('\t!BYTE\t${0:02X}, ${1:02X}, ${2:02X}\t; Percussion {3:d} Chan {4:d} Dur {5:d}'.format(deltatime, msg.note ^ 0x40, (lrchan << 7) | vol, msg.note, msg.channel, vol))
+                    if extperchan == 9: # Play percussion on both channels if no extended percussion
+                        print('\t!BYTE\t${0:02X}, ${1:02X}, ${2:02X}\t; Percussion {3:d} Chan {4:d} Dur {5:d}'.format(0, msg.note ^ 0x40, vol, msg.note, msg.channel, vol))
+                    eventtime = 0.0
+            else:
+                #
+                # Note
+                #
+                print('\t!BYTE\t${0:02X}, ${1:02X}, ${2:02X}\t; Note {3:d} Chan {4:d} Vol {5:d}'.format(deltatime, 0x80 | (octave << 4) | onote, (lrchan << 7) | vol, msg.note, msg.channel, vol))
                 eventtime = 0.0
-        else:
-            #
-            # Note
-            #
-            print('\t!BYTE\t${0:02X}, ${1:02X}, ${2:02X}\t; Note {3:d} Chan {4:d} Vol {5:d}'.format(deltatime, 0x80 | (octave << 4) | onote, (lrchan << 7) | vol, msg.note, msg.channel + 1, vol))
-            eventtime = 0.0
     elif msg.type == 'set_tempo':
         pass
         #timeshift = msg.tempo / 500000.0 * timescale
@@ -62,7 +68,7 @@ for msg in mid:
     elif msg.type == 'time_signature':
         pass
     elif msg.type == 'control_chage':
-        pass
+        print('; Control change Chan {0:d}'.format(msg.channel))
     elif msg.type == 'program_change':
-        pass
+        print('; Program change Chan {0:d}'.format(msg.channel))
 print('\t!BYTE\t${0:02X}, $00, $00'.format(int(eventtime + 0.5)))