Update utils.py

utils.py

@@ -402,7 +402,7 @@ def generate_audio_mp3(text: str, speaker: str) -> str:
             "model": "aura-asteria-en",  # female by default
         }
         if speaker == "John":
-            params["model"] = "aura-zeus-en"
+            params["model"] = "aura-helios-en"
 
         headers = {
             "Accept": "audio/mpeg",