diff --git a/scripts/selcal-detect.py b/scripts/selcal-detect.py
index cc080c9..72078a0 100755
--- a/scripts/selcal-detect.py
+++ b/scripts/selcal-detect.py
@@ -81,7 +81,7 @@ if __name__ == '__main__':
     pure_signals = {tone:note(freq, FLT_LEN, rate=sample_rate) for tone,freq in tones.items()}
     correlations = {tone:np.abs(signal.correlate(data, pure, mode='same')) for tone,pure in pure_signals.items()}
 
-    N = FLT_LEN # Rolling average length
+    N = FLT_LEN // 8 # Rolling average length
     cumsum_convolution = np.ones(N)/N
     massaged = {tone:np.convolve(correlation, cumsum_convolution, mode='valid') for tone,correlation in correlations.items()}