diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index 47df984ea..9037a6c43 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -71,7 +71,7 @@ void Machine::setup_output(float aspect_ratio)
 			"uint y = c & 14u;"
 			"uint iPhase = (c >> 4);"
 
-			"float phaseOffset = 6.283185308 * float(iPhase - 1u) / 13.0;"
+			"float phaseOffset = 6.283185308 * float(iPhase) / 13.0  + 5.074880441076923;"
 			"return mix(float(y) / 14.0, step(1, iPhase) * cos(phase + phaseOffset), amplitude);"
 		"}");
 	speaker_->set_input_rate((float)(get_clock_rate() / 38.0));