Hello all.  This is Irv.  The Beethoven String Quartet No. 15 Op. 132 played by the Alexander String Quartet (Arte Nova CD 1996) is worth a listen.  It is volume 9 of a set of 9, but can be purchased inexpensively as a separate CD.  Beethoven was not much for melody, but it is amazing how complex a sound he can get out of four instrumental voices.

I purchased the boxed set, which I got very inexpensively, but the above cited work is my clear favorite.