diff --git a/src/common/StateManager.hxx b/src/common/StateManager.hxx
index 1576a969d..018f07dad 100644
--- a/src/common/StateManager.hxx
+++ b/src/common/StateManager.hxx
@@ -18,7 +18,7 @@
 #ifndef STATE_MANAGER_HXX
 #define STATE_MANAGER_HXX
 
-#define STATE_HEADER "06070002state"
+#define STATE_HEADER "06070010state"
 
 class OSystem;
 class RewindManager;
diff --git a/src/emucore/tia/Audio.cxx b/src/emucore/tia/Audio.cxx
index 49b3145f6..76506da43 100644
--- a/src/emucore/tia/Audio.cxx
+++ b/src/emucore/tia/Audio.cxx
@@ -36,8 +36,10 @@ namespace {
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Audio::Audio()
 {
-  for (uInt8 i = 0; i <= 0x1e; ++i) myMixingTableSum[i] = mixingTableEntry(i, 0x1e);
-  for (uInt8 i = 0; i <= 0x0f; ++i) myMixingTableIndividual[i] = mixingTableEntry(i, 0x0f);
+  for (uInt8 i = 0; i <= 0x1e; ++i)
+    myMixingTableSum[i] = mixingTableEntry(i, 0x1e);
+  for (uInt8 i = 0; i <= 0x0f; ++i)
+    myMixingTableIndividual[i] = mixingTableEntry(i, 0x0f);
 
   reset();
 }
@@ -45,11 +47,9 @@ Audio::Audio()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Audio::reset()
 {
+  mySumChannel0 = mySumChannel1 = mySumCt = 0;
   myCounter = 0;
   mySampleIndex = 0;
-  sumChannel0 = 0;
-  sumChannel1 = 0;
-  sumCt = 0;
 
   myChannel0.reset();
   myChannel1.reset();
@@ -67,13 +67,11 @@ void Audio::setAudioQueue(const shared_ptr<AudioQueue>& queue)
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Audio::createSample()
 {
-  // calculate average of all recent volume samples. the average for each
+  // Calculate average of all recent volume samples. the average for each
   // channel is mixed to create a single audible value
-  const uInt8 sample0 = (uInt8)(sumChannel0/sumCt);
-  const uInt8 sample1 = (uInt8)(sumChannel1/sumCt);
-  sumChannel0 = 0;
-  sumChannel1 = 0;
-  sumCt = 0;
+  const auto sample0 = static_cast<uInt8>(mySumChannel0 / mySumCt);
+  const auto sample1 = static_cast<uInt8>(mySumChannel1 / mySumCt);
+  mySumChannel0 = mySumChannel1 = mySumCt = 0;
 
   addSample(sample0, sample1);
 #ifdef GUI_SUPPORT
@@ -115,6 +113,11 @@ bool Audio::save(Serializer& out) const
 
     if (!myChannel0.save(out)) return false;
     if (!myChannel1.save(out)) return false;
+
+    out.putInt(mySumChannel0);
+    out.putInt(mySumChannel1);
+    out.putInt(mySumCt);
+
   #ifdef GUI_SUPPORT
     out.putLong(static_cast<uInt64>(mySamples.size()));
     out.putByteArray(mySamples.data(), mySamples.size());
@@ -144,6 +147,11 @@ bool Audio::load(Serializer& in)
 
     if (!myChannel0.load(in)) return false;
     if (!myChannel1.load(in)) return false;
+
+    mySumChannel0 = in.getInt();
+    mySumChannel1 = in.getInt();
+    mySumCt = in.getInt();
+
   #ifdef GUI_SUPPORT
     const uInt64 sampleSize = in.getLong();
     ByteArray samples(sampleSize);
diff --git a/src/emucore/tia/Audio.hxx b/src/emucore/tia/Audio.hxx
index a18019b80..161e0c91f 100644
--- a/src/emucore/tia/Audio.hxx
+++ b/src/emucore/tia/Audio.hxx
@@ -68,9 +68,9 @@ class Audio : public Serializable
     AudioChannel myChannel0;
     AudioChannel myChannel1;
 
-	uInt32 sumChannel0;
-	uInt32 sumChannel1;
-	uInt32 sumCt;
+    uInt32 mySumChannel0{0};
+    uInt32 mySumChannel1{0};
+    uInt32 mySumCt{0};
 
     std::array<Int16, 0x1e + 1> myMixingTableSum;
     std::array<Int16, 0x0f + 1> myMixingTableIndividual;
@@ -96,11 +96,11 @@ class Audio : public Serializable
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Audio::tick()
 {
-  // volume for each channel is sampled every color clock. the average of
+  // Volume for each channel is sampled every color clock. the average of
   // these samples will be taken twice a scanline in the phase1() function
-  sumChannel0 += (uInt32)myChannel0.actualVolume();
-  sumChannel1 += (uInt32)myChannel1.actualVolume();
-  sumCt++;
+  mySumChannel0 += static_cast<uInt32>(myChannel0.actualVolume());
+  mySumChannel1 += static_cast<uInt32>(myChannel1.actualVolume());
+  mySumCt++;
 
   switch (myCounter) {
     case 9:
diff --git a/src/emucore/tia/AudioChannel.cxx b/src/emucore/tia/AudioChannel.cxx
index ad82fd801..679a92cd3 100644
--- a/src/emucore/tia/AudioChannel.cxx
+++ b/src/emucore/tia/AudioChannel.cxx
@@ -120,9 +120,10 @@ void AudioChannel::phase1()
   }
 }
 
-// the actual volume of a chaneel is the volume register multiplied by the
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+// The actual volume of a chaneel is the volume register multiplied by the
 // lowest of the pulse counter
-uInt8 AudioChannel::actualVolume() 
+uInt8 AudioChannel::actualVolume() const
 {
   return (myPulseCounter & 0x01) * myAudv;
 }
diff --git a/src/emucore/tia/AudioChannel.hxx b/src/emucore/tia/AudioChannel.hxx
index ed62afafb..fc292ff6d 100644
--- a/src/emucore/tia/AudioChannel.hxx
+++ b/src/emucore/tia/AudioChannel.hxx
@@ -32,7 +32,7 @@ class AudioChannel : public Serializable
 
     void phase1();
 
-	uInt8 actualVolume();
+    uInt8 actualVolume() const;
 
     void audc(uInt8 value);