diff --git a/MicroDexed.ino b/MicroDexed.ino
index 0160e07..13953fe 100644
--- a/MicroDexed.ino
+++ b/MicroDexed.ino
@@ -831,7 +831,7 @@ void handleSystemExclusive(byte * sysex, uint len)
         MicroDexed[instance_id]->controllers.breath.setTarget(MicroDexed[instance_id]->data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_BREATHCTRL_ASSIGN]);
         MicroDexed[instance_id]->controllers.at.setRange(MicroDexed[instance_id]->data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_AT_RANGE]);
         MicroDexed[instance_id]->controllers.at.setTarget(MicroDexed[instance_id]->data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_AT_ASSIGN]);
-        MicroDexed[instance_id]->controllers.masterTune = (MicroDexed[instance_id]->data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_MASTER_TUNE] * 0x4000 << 11) * (1.0 / 12);
+        MicroDexed[instance_id]->controllers.masterTune = (MicroDexed[instance_id]->data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_MASTER_TUNE] / 10 * 0x4000 << 11) * (1.0 / 12);
         MicroDexed[instance_id]->controllers.refresh();
         data_index = DEXED_GLOBAL_PARAMETER_OFFSET - 63 + sysex[4];
       }
diff --git a/dexed.cpp b/dexed.cpp
index a10962c..670df5d 100644
--- a/dexed.cpp
+++ b/dexed.cpp
@@ -545,7 +545,7 @@ bool Dexed::loadGlobalParameters(uint8_t* new_data)
   controllers.breath.setTarget(new_data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_BREATHCTRL_ASSIGN]);
   controllers.at.setRange(new_data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_AT_RANGE]);
   controllers.at.setTarget(new_data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_AT_ASSIGN]);
-  controllers.masterTune = (new_data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_MASTER_TUNE] * 0x4000 << 11) * (1.0 / 12);
+  controllers.masterTune = (new_data[DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_MASTER_TUNE] / 10 * 0x4000 << 11) * (1.0 / 12);
   controllers.refresh();
 
   setOPs((*(p_data + DEXED_GLOBAL_PARAMETER_OFFSET + DEXED_OP1_ENABLE) << 5) |