diff --git a/mp3gain_tracks.sh b/mp3gain_tracks.sh
index 7f53738..3e2803e 100755
--- a/mp3gain_tracks.sh
+++ b/mp3gain_tracks.sh
@@ -11,7 +11,13 @@ if [ -z "$CONCURRENCY_LEVEL" ]; then
 fi
 
 echo "Processing using $CONCURRENCY_LEVEL processes..."
-nice -n2 find "$@" -print0 | xargs -0 -P $CONCURRENCY_LEVEL -n 1 -I {} mp3gain -q -k -p -r -s i "{}"
+#  -q - Quiet mode: no status messages
+#  -k - automatically lower Track/Album gain to not clip audio
+#  -p - Preserve original file timestamp
+#  -r - apply Track gain automatically (all files set to equal loudness)
+#  -s i - use ID3v2 tag for MP3 gain info
+#  -d <n> - modify suggested dB gain (89dB) by floating-point n
+nice -n2 find "$@" -print0 | xargs -0 -P $CONCURRENCY_LEVEL -n 1 -I {} mp3gain -q -k -p -r -s i -d 4.0 "{}"
 #nice -n2 find "$@" -print0 | xargs -0 -P $CONCURRENCY_LEVEL -n 1 -I {} replaygain --no-album "{}"
 
 echo "All done."