diff --git a/render.py b/render.py
index b70fee8..361f8ea 100644
--- a/render.py
+++ b/render.py
@@ -586,8 +586,9 @@ def render_all(options):
                     "-i", fragment_prefix / "audio-center.wav",
                     "-i", fragment_prefix / "audio-rear.wav",
                     "-i", fragment_prefix / audio_back,
-                    "-filter_complex", "[0:a][1:a][2:a][3:a]amerge=inputs=2[a]",
-                    "-map", "[a]", '-ac', '2', fragment_prefix / "audio-stereo.wav"
+                    "-filter_complex",
+                    "amix=inputs=4:duration=longest:dropout_transition=0",
+                    '-ac', '2', fragment_prefix / "audio-stereo.wav"
                 ])
                 audio_front = "audio-stereo.wav"
                 audio_back = "audio-stereo.wav"