diff --git a/src/damaris/data/DamarisFFT.py b/src/damaris/data/DamarisFFT.py
index def34e6..a4b43e2 100644
--- a/src/damaris/data/DamarisFFT.py
+++ b/src/damaris/data/DamarisFFT.py
@@ -63,7 +63,7 @@ class DamarisFFT:
         # Heuer, A; Haeberlen, U.: J. Mag. Res.(1989) 85, Is 1, 79-94
         n = int( self.x.size * last_part )
         for ch in range( len( self.y ) ):
-            self.y[ ch ] -= self.y[ ch ][ -n: ].mean( )
+            self.y[ ch ] = self.y[ ch ] - self.y[ ch ][ -n: ].mean( )
         return self
 
     def exp_window( self, line_broadening=10 ):