diff --git a/preprocess.py b/preprocess.py
index d0cb6e5..6d2649a 100644
--- a/preprocess.py
+++ b/preprocess.py
@@ -29,6 +29,7 @@ if __name__ == "__main__":
             # custom character voices need to be at least equal to number of sample_audio4ft
             num_character_voices = len(custom_character_anno)
             cc_duplicate = num_old_voices // num_character_voices
+            cc_duplicate = 1 if num_character_voices >= num_old_voices else cc_duplicate
             final_annos = final_annos + custom_character_anno * cc_duplicate
     # save annotation file
     with open("final_annotation_train.txt", 'w', encoding='utf-8') as f: