diff --git a/app/dl_formats.py b/app/dl_formats.py
index 68e73bf..961ca1c 100644
--- a/app/dl_formats.py
+++ b/app/dl_formats.py
@@ -27,7 +27,7 @@ def get_format(format: str, quality: str) -> str:
 
     if format in AUDIO_FORMATS:
         # Audio quality needs to be set post-download, set in opts
-        return "bestaudio/best"
+        return f"bestaudio[ext={format}]/bestaudio/best"
 
     if format in ("mp4", "any"):
         if quality == "audio":