Audiotape assessments

Using audiotapes to assess students seems to save time for the teacher in the long run since they tell each student individually how to improve their work.  However, the most important part of an audiotape assessment is that the students may actually listen to what the teacher has to say.  When I hand out graded papers, even though I go over the correct answers, the students are only interested in the grade on the front.  For the most part, they don't bother to look at their errors and learn from them.  I would like to possibly use my DVR for a goal next year in supplying audio assessments for my students.  I am going to have to give this more thought, though, because this could get very expensive buying CDs to burn.  I like that the teacher mentioned in Marzano's book got cassette players for each of her students to listen to their audio assessments.  Now, all I have to figure out is how to apply that to the newer technology of digital voice recorders.