Rename the downloadable file using either title or tags?

Though I have enabled "Description field:" in the field for the content type, it doesn't present me with a field on the create content form to input text. This field appears when uploading mp3s via filefield and audiofield but oddly enough not when uploading from audiorecorderfield. It'd be great to have the mp3 named something other then the current "73483739.mp3" default format.