diff --git a/lib/hooks/rms.cpp b/lib/hooks/rms.cpp
index 09699f761..3f85de5a8 100644
--- a/lib/hooks/rms.cpp
+++ b/lib/hooks/rms.cpp
@@ -102,12 +102,12 @@ public:
 			/* Square the new value */
 			double newValue = pow(smp->data[index].f, 2);
 
+			/* Get the old value from the history */
+			double oldValue = smpMemory[i][smpMemoryPosition % windowSize];
+
 			/* Append the new value to the history memory */
 			smpMemory[i][smpMemoryPosition % windowSize] = newValue;
 
-			/* Get the old value from the history */
-			double oldValue = smpMemory[i][(smpMemoryPosition + 1) % windowSize];
-
 			/* Update the accumulator */
 			accumulator[index] += newValue;
 			accumulator[index] -= oldValue;