diff --git a/README.md b/README.md
index 7d89769..9d153b7 100644
--- a/README.md
+++ b/README.md
@@ -33,8 +33,6 @@ Install other packages:
 pip install -r requirements.txt
 ```
 
-**Note**: install numpy with version < 2.x, e.g. `pip install numpy==1.22.0`.
-
 ## Prepare Dataset
 
 Example data processing scripts for Emilia and Wenetspeech4TTS, and you may tailor your own one along with a Dataset class in `model/dataset.py`.
diff --git a/gradio_app.py b/gradio_app.py
index 104a7d8..58970e5 100644
--- a/gradio_app.py
+++ b/gradio_app.py
@@ -280,7 +280,7 @@ def infer_batch(ref_audio, ref_text, gen_text_batches, exp_name, remove_silence,
 
     return (target_sample_rate, final_wave), spectrogram_path
 
-def infer(ref_audio_orig, ref_text, gen_text, exp_name, remove_silence, custom_split_words):
+def infer(ref_audio_orig, ref_text, gen_text, exp_name, remove_silence, custom_split_words=''):
     if not custom_split_words.strip():
         custom_words = [word.strip() for word in custom_split_words.split(',')]
         global SPLIT_WORDS
diff --git a/requirements.txt b/requirements.txt
index fa63937..4a6e71e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,6 +12,7 @@ jieba
 jiwer
 librosa
 matplotlib
+numpy==1.23.5
 pydub
 pypinyin
 safetensors