diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index ba56db751..af59e0fba 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -24,7 +24,8 @@ Machine::Machine() :
 	_upcomingEventsPointer(0),
 	_objectCounterPointer(0),
 	_stateByTime(_stateByExtendTime[0]),
-	_cycles_since_speaker_update(0)
+	_cycles_since_speaker_update(0),
+	_is_pal_region(false)
 {
 	memset(_collisions, 0xff, sizeof(_collisions));
 	set_reset_line(true);
@@ -57,6 +58,7 @@ Machine::Machine() :
 void Machine::setup_output(float aspect_ratio)
 {
 	_crt = new Outputs::CRT::CRT(228, 1, 263, Outputs::CRT::ColourSpace::YIQ, 228, 1, 1);
+	_crt->set_output_device(Outputs::CRT::Television);
 
 	// this is the NTSC phase offset function; see below for PAL
 	_crt->set_composite_sampling_function(
@@ -69,9 +71,7 @@ void Machine::setup_output(float aspect_ratio)
 			"float phaseOffset = 6.283185308 * float(iPhase - 1u) / 13.0;"
 			"return mix(float(y) / 14.0, step(1, iPhase) * cos(phase + phaseOffset), amplitude);"
 		"}");
-	_crt->set_output_device(Outputs::CRT::Television);
-
-	_speaker.set_input_rate(1194720 / 38);
+	_speaker.set_input_rate((float)(get_clock_rate() / 38.0));
 }
 
 void Machine::switch_region()
@@ -89,9 +89,13 @@ void Machine::switch_region()
 			"phaseOffset *= 6.283185308 / 12.0;"
 			"return mix(float(y) / 14.0, step(4, (iPhase + 2u) & 15u) * cos(phase + phaseOffset), amplitude);"
 		"}");
+
 	_crt->set_new_timing(228, 312, Outputs::CRT::ColourSpace::YUV, 228, 1);
 
-//	_speaker.set_input_rate(2 * 312 * 50);
+	_is_pal_region = true;
+	_speaker.set_input_rate((float)(get_clock_rate() / 38.0));
+
+	if(delegate) delegate->machine_did_change_clock_rate(this);
 }
 
 void Machine::close_output()
@@ -106,6 +110,11 @@ Machine::~Machine()
 	close_output();
 }
 
+double Machine::get_clock_rate()
+{
+	return _is_pal_region ? 1182298 : 1194720;
+}
+
 void Machine::update_timers(int mask)
 {
 	unsigned int upcomingPointerPlus4 = (_upcomingEventsPointer + 4)%number_of_upcoming_events;
@@ -733,7 +742,6 @@ void Machine::set_switch_is_enabled(Atari2600Switch input, bool state)
 	}
 }
 
-
 void Machine::set_rom(size_t length, const uint8_t *data)
 {
 	_rom_size = 1024;
@@ -816,7 +824,6 @@ void Atari2600::Speaker::set_control(int channel, uint8_t control)
 #define advance_poly5(c) _poly5_counter[channel] = (_poly5_counter[channel] >> 1) | (((_poly5_counter[channel] << 4) ^ (_poly5_counter[channel] << 2))&0x010)
 #define advance_poly9(c) _poly9_counter[channel] = (_poly9_counter[channel] >> 1) | (((_poly9_counter[channel] << 4) ^ (_poly9_counter[channel] << 8))&0x100)
 
-
 void Atari2600::Speaker::get_samples(unsigned int number_of_samples, int16_t *target)
 {
 	for(unsigned int c = 0; c < number_of_samples; c++)
diff --git a/Machines/Atari2600/Atari2600.hpp b/Machines/Atari2600/Atari2600.hpp
index 08b3a3fef..c8e3fa53a 100644
--- a/Machines/Atari2600/Atari2600.hpp
+++ b/Machines/Atari2600/Atari2600.hpp
@@ -95,7 +95,7 @@ class Machine: public CPU6502::Processor<Machine>, public CRTMachine::Machine {
 		virtual Outputs::CRT::CRT *get_crt() { return _crt; }
 		virtual Outputs::Speaker *get_speaker() { return &_speaker; }
 		virtual void run_for_cycles(int number_of_cycles) { CPU6502::Processor<Machine>::run_for_cycles(number_of_cycles); }
-		virtual double get_clock_rate() { return 1194720; }
+		virtual double get_clock_rate();
 		// TODO: different rate for PAL
 
 	private:
@@ -200,6 +200,9 @@ class Machine: public CPU6502::Processor<Machine>, public CRTMachine::Machine {
 		Outputs::CRT::CRT *_crt;
 		Speaker _speaker;
 
+		// current mode
+		bool _is_pal_region;
+
 		// speaker backlog accumlation counter
 		unsigned int _cycles_since_speaker_update;
 		void update_audio();
diff --git a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift
index fa81b1509..0a0c55194 100644
--- a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
+++ b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
@@ -12,6 +12,7 @@ import AudioToolbox
 class MachineDocument:
 	NSDocument,
 	NSWindowDelegate,
+	CSMachineDelegate,
 	CSOpenGLViewDelegate,
 	CSOpenGLViewResponderDelegate,
 	CSBestEffortUpdaterDelegate,
@@ -56,6 +57,15 @@ class MachineDocument:
 			self.machine().setView(self.openGLView, aspectRatio: Float(displayAspectRatio.width / displayAspectRatio.height))
 		})
 
+		setupClockRate()
+		self.machine().delegate = self
+	}
+
+	func machineDidChangeClockRate(machine: CSMachine!) {
+		setupClockRate()
+	}
+
+	private func setupClockRate() {
 		// establish and provide the audio queue, taking advice as to an appropriate sampling rate
 		let maximumSamplingRate = CSAudioQueue.preferredSamplingRate()
 		let selectedSamplingRate = self.machine().idealSamplingRateFromRange(NSRange(location: 0, length: NSInteger(maximumSamplingRate)))
diff --git a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm
index f5d577749..dcc21d12c 100644
--- a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
+++ b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
@@ -12,6 +12,7 @@
 
 @interface CSMachine()
 - (void)speaker:(Outputs::Speaker *)speaker didCompleteSamples:(const int16_t *)samples length:(int)length;
+- (void)machineDidChangeClockRate;
 @end
 
 struct SpeakerDelegate: public Outputs::Speaker::Delegate {
@@ -21,14 +22,37 @@ struct SpeakerDelegate: public Outputs::Speaker::Delegate {
 	}
 };
 
+struct MachineDelegate: CRTMachine::Machine::Delegate {
+	__weak CSMachine *machine;
+	void machine_did_change_clock_rate(CRTMachine::Machine *sender) {
+		[machine machineDidChangeClockRate];
+	}
+};
+
 @implementation CSMachine {
 	SpeakerDelegate _speakerDelegate;
+	MachineDelegate _machineDelegate;
+}
+
+- (instancetype)init {
+	self = [super init];
+	if(self)
+	{
+		_machineDelegate.machine = self;
+		self.machine->set_delegate(&_machineDelegate);
+		_speakerDelegate.machine = self;
+	}
+	return self;
 }
 
 - (void)speaker:(Outputs::Speaker *)speaker didCompleteSamples:(const int16_t *)samples length:(int)length {
 	[self.audioQueue enqueueAudioBuffer:samples numberOfSamples:(unsigned int)length];
 }
 
+- (void)machineDidChangeClockRate {
+	[self.delegate machineDidChangeClockRate:self];
+}
+
 - (void)dealloc {
 	[_view performWithGLContext:^{
 		@synchronized(self) {
@@ -50,7 +74,6 @@ struct SpeakerDelegate: public Outputs::Speaker::Delegate {
 
 - (void)setAudioSamplingRate:(float)samplingRate bufferSize:(NSUInteger)bufferSize {
 	@synchronized(self) {
-		_speakerDelegate.machine = self;
 		[self setSpeakerDelegate:&_speakerDelegate sampleRate:samplingRate bufferSize:bufferSize];
 	}
 }