As far as sound files go, only .au files can be played by the applet and then only those files in the applet’s working directory. If the file is not on the webserver then it will not be played. Playing .mp3, .wav or other sound files to the room can be done with other IRC clients such as mIRC or Klient. But, even so, only others with that same sound file on their own computer would be able to hear it. Otherwise one would need to stream the sound to others in the room and this is *not* possible with any IRC daemon that I am aware of. Nor do I believe that any of the standard IRC clients available support live streaming of audio in such a mode.