The others are right. Trying to stream from a torrent seems wasteful and complex.

But if you must for some strange reason, perhaps it would work to use webtor.io to produce an http-reachable audio file which could be curl/wget-fetched and piped to an audio decoder/player. I doubt you could make webtor fetch pieces linearly from the beginning. You would likely have to wait until the last piece is fetched to start streaming.