Capturing streaming audio to a mp3 file using lame.

I'm attempting to save a short streaming audio clip to an mp3 file. I set Capture with alsamixer to 100% and then used the Code:arecord -f cd -t raw | lame -x -r - out.mp3 command.

The resultant mp3 file is 544k and identifies as mp3 using the file command. Unfortunately, playing the file with ffplay or gmplayer produces no sound.