diff --git a/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.Audio.cs b/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.Audio.cs
index e44deff1c4..585a9c3d37 100644
--- a/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.Audio.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.Audio.cs
@@ -25,6 +25,9 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			// 5 bit shift register
 			private int sr5 = 0x1f;
 
+            // 9 bit shift register
+            private int sr9 = 0x1ff;
+
 			// 3 state counter
 			private int sr3 = 2;
 
@@ -49,7 +52,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			private bool Run4()
 			{
 				bool ret = (sr4 & 1) != 0;
-				bool c = (sr4 & 1) != 0 ^ (sr4 & 2) != 0;
+				bool c = ((sr4 & 1) != 0) ^ ((sr4 & 2) != 0);
 				sr4 = (sr4 >> 1) | (c ? 8 : 0);
 				return ret;
 			}
@@ -57,7 +60,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			private bool Run5()
 			{
 				bool ret = (sr5 & 1) != 0;
-				bool c = (sr5 & 1) != 0 ^ (sr5 & 4) != 0;
+				bool c = ((sr5 & 1) != 0) ^ ((sr5 & 4) != 0);
 				sr5 = (sr5 >> 1) | (c ? 16 : 0);
 				return ret;
 			}
@@ -84,12 +87,11 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 
 			private bool Run9()
 			{
-				bool ret = (sr4 & 1) != 0;
-				bool c = (sr5 & 1) != 0 ^ (sr4 & 1) != 0;
-				sr4 = (sr4 >> 1) | ((sr5 & 1) != 0 ? 8 : 0);
-				sr5 = (sr5 >> 1) | (c ? 16 : 0);
-				return ret;
-			}
+                bool ret = (sr9 & 1) != 0;
+                bool c = ((sr9 & 1) != 0) ^ ((sr9 & 16) != 0);
+                sr9 = (sr9 >> 1) | (c ? 256 : 0);
+                return ret;
+            }
 
 			/// <summary>
 			/// call me approx 31k times a second
@@ -112,20 +114,16 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 						case 0x01:
 							// Both run, but the 5 bit is ignored
 							on = Run4();
-							Run5();
+							//Run5();
 							break;
-
 						case 0x02:
 							if ((sr5 & 0x0f) == 0 || (sr5 & 0x0f) == 0x0f)
 							{
 								on = Run4();
-                                Run5();
-								break;
 							}
 
 							Run5();
 							break;
-
 						case 0x03:
 							if (Run5())
 							{
@@ -145,10 +143,9 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 							Run4();
 							on = Run1();
 							break;
-
+                            
 						case 0x06:
 						case 0x0a:
-							Run4(); // ???
 							Run5();
 							if ((sr5 & 0x0f) == 0)
 							{
@@ -163,9 +160,9 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 
 						case 0x07:
 						case 0x09:
-							Run4(); // ???
 							on = Run5();
 							break;
+                            
 						case 0x08:
 							on = Run9();
 							break;
@@ -206,7 +203,8 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 				ser.Sync("sr3", ref sr3);
 				ser.Sync("sr4", ref sr4);
 				ser.Sync("sr5", ref sr5);
-				ser.Sync("freqcnt", ref freqcnt);
+                ser.Sync("sr9", ref sr9);
+                ser.Sync("freqcnt", ref freqcnt);
 				ser.Sync("on", ref on);
 			}
 		}