diff --git a/SOURCES.md b/SOURCES.md
index 9e527a0..0a1f4ed 100644
--- a/SOURCES.md
+++ b/SOURCES.md
@@ -34,6 +34,13 @@ Backgrounds
 Backgrounds marked with a * are placeholders that will be replaced in later versions due to incompatible licenses. We are generally aiming for public domain background images, but will also accept backgrounds given proper licenses to be included within Cambridge.
 
 
+Sounds
+------
+
+All piece sounds are (c) 2020 Damian Yerrick.
+Ready / go sounds from NullpoMino.
+Menu sounds from TGM3 (will be replaced.)
+
 Music
 -----
 
diff --git a/res/se/piece_i.wav b/res/se/piece_i.wav
index a155c9d..b4cfd66 100644
Binary files a/res/se/piece_i.wav and b/res/se/piece_i.wav differ
diff --git a/res/se/piece_j.wav b/res/se/piece_j.wav
index 158365e..f17c56b 100644
Binary files a/res/se/piece_j.wav and b/res/se/piece_j.wav differ
diff --git a/res/se/piece_l.wav b/res/se/piece_l.wav
index 148a82f..9d9a537 100644
Binary files a/res/se/piece_l.wav and b/res/se/piece_l.wav differ
diff --git a/res/se/piece_o.wav b/res/se/piece_o.wav
index 26dab85..730593c 100644
Binary files a/res/se/piece_o.wav and b/res/se/piece_o.wav differ
diff --git a/res/se/piece_s.wav b/res/se/piece_s.wav
index 3e23b06..e215cf1 100644
Binary files a/res/se/piece_s.wav and b/res/se/piece_s.wav differ
diff --git a/res/se/piece_t.wav b/res/se/piece_t.wav
index 07da609..5d6ea9f 100644
Binary files a/res/se/piece_t.wav and b/res/se/piece_t.wav differ
diff --git a/res/se/piece_z.wav b/res/se/piece_z.wav
index 469e39c..b86d604 100644
Binary files a/res/se/piece_z.wav and b/res/se/piece_z.wav differ