diff --git a/Interpreter.cpp b/Interpreter.cpp
index 2992a86..213a162 100644
--- a/Interpreter.cpp
+++ b/Interpreter.cpp
@@ -145,16 +145,16 @@ void Interpreter::tick() {
   case 0xF000: // several unique instructions
     switch(inst & 0xF0FF) {
     case 0xF007: // FX07 - read timer register
-      mvReg[iRegDst] = (mvSpecialReg[SR_T1] + mcTicksPerSecond - 1) / mcTicksPerSecond;
+      mvReg[iRegDst] = (mvSpecialReg[SR_T1] * scTimerFreq + (mcTicksPerSecond - 1)) / mcTicksPerSecond;
       break;
     case 0xF015: // FX15 - set timer register
-      mvSpecialReg[SR_T1] = mcTicksPerSecond * mvReg[iRegDst];
+      mvSpecialReg[SR_T1] = (mcTicksPerSecond * mvReg[iRegDst]) / scTimerFreq;
       break;
     case 0xF018: // FX18 - set sound timer register
-      if(mvSpecialReg[SR_T1] == 0 && mvReg[iRegDst] != 0) {
+      if(mvSpecialReg[SR_T2] == 0 && mvReg[iRegDst] != 0) {
         mrBuzzer.on();
       }
-      mvSpecialReg[SR_T1] = mcTicksPerSecond * mvReg[iRegDst];
+      mvSpecialReg[SR_T2] = (mcTicksPerSecond * mvReg[iRegDst]) / scTimerFreq;
       break;
     case 0xF01E: // FX1E - add to I
       mvSpecialReg[SR_I] += mvReg[iRegDst];
diff --git a/Interpreter.hpp b/Interpreter.hpp
index 83c38d2..362da0c 100644
--- a/Interpreter.hpp
+++ b/Interpreter.hpp
@@ -16,6 +16,7 @@ private:
 public:
   constexpr static sreg_t scLowRestFontAddr = 0x0000;
   constexpr static sreg_t scResetVector = 0x0200;
+  constexpr static sreg_t scTimerFreq = 60;
   constexpr static size_t scMemorySize = 4096;
 
   enum {