I am not 100% certain on this..(or even 10% certain) but being that rm is a proprietary format there is no way to decode it in the way you want.
You may, however, be able to play the file...and use another app to read the raw sound data from your soundcard and record it to a format of your choosing.
Probably the easiest way to do what you want is go to a store and buy the Wagner CD. As he is long since dead...I'm sure you can pick it up for very little cost. I have found that many cds of classical music by the "greats" (bach, beethoven, mozart et al) are $3-$5 because the copyright has expired and the music is in the public domain.
Here's another solution. Free mp3 download -->
http://www.mp3-find.com/mp3-RichardW...ries-22330.asp
If you need a wav then:
Code:
# mpg123 -w <songtitle>.wav <songtitle>.mp3
HTH