diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index 8abeb1d67..e3d732b9e 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -38,7 +38,7 @@ Machine::Machine() :
 void Machine::setup_output(float aspect_ratio) {
 	bus_->tia_.reset(new TIA);
 	bus_->speaker_.reset(new Speaker);
-	bus_->speaker_->set_input_rate((float)(get_clock_rate() / 38.0));
+	bus_->speaker_->set_input_rate((float)(get_clock_rate() / (double)CPUTicksPerAudioTick));
 	bus_->tia_->get_crt()->set_delegate(this);
 }
 
@@ -149,8 +149,8 @@ void Machine::crt_did_end_batch_of_frames(Outputs::CRT::CRT *crt, unsigned int n
 				bus_->tia_->set_output_mode(TIA::OutputMode::PAL);
 			}
 
-			bus_->speaker_->set_input_rate((float)(clock_rate / 38.0));
-			bus_->speaker_->set_high_frequency_cut_off((float)(clock_rate / (38.0 * 2.0)));
+			bus_->speaker_->set_input_rate((float)(clock_rate / (double)CPUTicksPerAudioTick));
+			bus_->speaker_->set_high_frequency_cut_off((float)(clock_rate / ((double)CPUTicksPerAudioTick * 2.0)));
 			set_clock_rate(clock_rate);
 		}
 	}
diff --git a/Machines/Atari2600/Atari2600.hpp b/Machines/Atari2600/Atari2600.hpp
index 9147e3f95..550ec3db3 100644
--- a/Machines/Atari2600/Atari2600.hpp
+++ b/Machines/Atari2600/Atari2600.hpp
@@ -23,9 +23,6 @@
 
 namespace Atari2600 {
 
-const unsigned int number_of_upcoming_events = 6;
-const unsigned int number_of_recorded_counters = 7;
-
 class Machine:
 	public CRTMachine::Machine,
 	public ConfigurationTarget::Machine,
diff --git a/Machines/Atari2600/Bus.hpp b/Machines/Atari2600/Bus.hpp
index 864d22715..8d5d731a9 100644
--- a/Machines/Atari2600/Bus.hpp
+++ b/Machines/Atari2600/Bus.hpp
@@ -9,9 +9,10 @@
 #ifndef Atari2600_Bus_hpp
 #define Atari2600_Bus_hpp
 
+#include "Atari2600.hpp"
 #include "PIA.hpp"
-#include "TIA.hpp"
 #include "Speaker.hpp"
+#include "TIA.hpp"
 
 namespace Atari2600 {
 
@@ -38,8 +39,8 @@ class Bus {
 		// speaker backlog accumlation counter
 		unsigned int cycles_since_speaker_update_;
 		inline void update_audio() {
-			unsigned int audio_cycles = cycles_since_speaker_update_ / 114;
-			cycles_since_speaker_update_ %= 114;
+			unsigned int audio_cycles = cycles_since_speaker_update_ / (CPUTicksPerAudioTick * 3);
+			cycles_since_speaker_update_ %= (CPUTicksPerAudioTick * 3);
 			speaker_->run_for_cycles(audio_cycles);
 		}
 
diff --git a/Machines/Atari2600/Speaker.hpp b/Machines/Atari2600/Speaker.hpp
index b5bf42488..3cf5afc9c 100644
--- a/Machines/Atari2600/Speaker.hpp
+++ b/Machines/Atari2600/Speaker.hpp
@@ -13,6 +13,8 @@
 
 namespace Atari2600 {
 
+const int CPUTicksPerAudioTick = 38;
+
 class Speaker: public ::Outputs::Filter<Speaker> {
 	public:
 		Speaker();