diff --git a/dbm_lib/dbm_features/raw_features/audio/formant_freq.py b/dbm_lib/dbm_features/raw_features/audio/formant_freq.py
index 592ebdc3..2d2eff92 100644
--- a/dbm_lib/dbm_features/raw_features/audio/formant_freq.py
+++ b/dbm_lib/dbm_features/raw_features/audio/formant_freq.py
@@ -31,7 +31,11 @@ def formant_list(formant,snd):
     Returns:
         List of first through fourth formant for each frame
     """
-    f1_list, f2_list, f3_list, f4_list = ([], ) * 4
+    f1_list = []
+    f2_list = []
+    f3_list = []
+    f4_list = []
+    
     dur = snd.duration-0.02
     dur_round = round(dur, 2)
     
@@ -126,4 +130,4 @@ def run_formant(video_uri, out_dir, r_config):
 
             calc_formant(video_uri, audio_file, out_loc, fl_name, r_config)
     except Exception as e:
-        logger.error('Failed to process audio file')
\ No newline at end of file
+        logger.error('Failed to process audio file')