I could of course explain that BS.Player started off as a pure (advanced) videoplayer and that audio features were only added afterwards upon users' requests, but that doesn't really help you, now does it?
Anyhow, you posted this in the right forum "Feature requests". So, let's keep our fingers crossed and perhaps the creator(s) of BS.Player will add this as a new (user selectable) feature in one of its future releases.