diff --git a/assets/bounce-marimba.wav b/assets/bounce-marimba.wav
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diff --git a/assets/break-off-autosinfonie-spatialized.wav b/assets/break-off-autosinfonie-spatialized.wav
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diff --git a/assets/contact-lower.wav b/assets/contact-lower.wav
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diff --git a/assets/harp-pickup.wav b/assets/harp-pickup.wav
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diff --git a/assets/simple-drop.wav b/assets/simple-drop.wav
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diff --git a/sounds/bounce-marimba.mp3 b/sounds/bounce-marimba.mp3
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diff --git a/sounds/break-off-autosinfonie-spatialized.mp3 b/sounds/break-off-autosinfonie-spatialized.mp3
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diff --git a/sounds/contact-lower.mp3 b/sounds/contact-lower.mp3
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diff --git a/sounds/harp-drop.mp3 b/sounds/harp-drop.mp3
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diff --git a/sounds/harp-pickup.mp3 b/sounds/harp-pickup.mp3
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diff --git a/sounds/license.json b/sounds/license.json
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index 00000000..3fcf3eea
--- /dev/null
+++ b/sounds/license.json
@@ -0,0 +1,58 @@
+{
+  "bounce-marimba.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  },
+  "break-off-autosinfonie-spatialized.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  },
+  "contact-lower.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  },
+  "harp-drop.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  },
+  "harp-pickup.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  },
+  "simple-drop.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  },
+  "simple-pickup.mp3": {
+    "text": [
+      "Copyright 2018 University of Colorado Boulder"
+    ],
+    "projectURL": "http://phet.colorado.edu",
+    "license": "contact phethelp@colorado.edu",
+    "notes": "created by Mike Winters for use by PhET"
+  }
+}
\ No newline at end of file
diff --git a/sounds/simple-drop.mp3 b/sounds/simple-drop.mp3
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