diff --git a/data_utils/speech.py b/data_utils/speech.py
index 0cea88730..e64109dc8 100644
--- a/data_utils/speech.py
+++ b/data_utils/speech.py
@@ -3,6 +3,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import numpy as np
 from data_utils.audio import AudioSegment