diff --git a/render.py b/render.py
index f58de92..47c491e 100644
--- a/render.py
+++ b/render.py
@@ -105,8 +105,9 @@ def compose(clips, target=150, base=1024, voice_over=None):
             })
             vo_min += offset
         for vo in voice_overs:
-            vo_low['filter'] = {'volume': '3'}
-            scene['audio-center']['A1'].append(vo)
+            voc = vo.copy()
+            voc['filter'] = {'volume': '3'}
+            scene['audio-center']['A1'].append(voc)
             vo_low = vo.copy()
             vo_low['filter'] = {'volume': '-6'}
             scene['audio-rear']['A1'].append(vo_low)