At C-Span classroom they have posted several 3-5 minute clips from C-Span scholars, politicians, judges, etc on the various elements of the constitution. They are organized within the text of the Constitution on that page, and can be played directly from their website.
If you create a teacher login for C-Span Classroom, then you can save clips to a personal library or playlist.
http://www.c-spanclassroom.org/Members/Constitution-Clips.aspx