diff --git a/scripts/acoustics.py b/scripts/acoustics.py
index b2d2f01118bca5c80c70045256c9b9584224ce06..661cf324ea2b992bee7a7f1910d6c76d0861ca97 100755
--- a/scripts/acoustics.py
+++ b/scripts/acoustics.py
@@ -9,7 +9,7 @@ Usage:
 
 Options:
     -d DET_ID       Detector ID.
-    -o PLOT_DIR     The directory to save the plot.
+    -o PLOT_DIR     The directory to save the plot [default: plots].
     -h --help       Show this screen.
 
 """