diff --git a/230101/test_render.sh b/230101/test_render.sh
index 09c09bf..60d00a3 100755
--- a/230101/test_render.sh
+++ b/230101/test_render.sh
@@ -28,7 +28,7 @@ ffmpeg \
 	-f concat \
 	-safe 0 \
 	-i "$lecture/recording.txt" \
-	-af "pan=stereo|c0=c0|c1=c0,aformat=sample_rates=48000" \
+	-af "loudnorm,pan=stereo|c0=c0|c1=c0,aformat=sample_rates=48000" \
 	-c:v copy -b:a 128000 \
 	"$lecture/recording.mp4"