diff --git a/core/_11_merge_audio.py b/core/_11_merge_audio.py
index 41c8ac16..3fb932d8 100644
--- a/core/_11_merge_audio.py
+++ b/core/_11_merge_audio.py
@@ -1,4 +1,5 @@
 import os
+import numpy as np
 import pandas as pd
 import subprocess
 from pydub import AudioSegment