Charlie Haden  (August 6, 1937 – July 11, 2014) was an American jazz double bass player, bandleader, composer, and educator known for his deep, warm sound, and whose career spanned more than fifty years.  In the late 1950s, Haden was an original member of the ground-breaking Ornette Coleman Quartet.  Haden revolutionized the harmonic concept of bass playing in jazz.  About him, German musicologist Joachim-Ernst Berendt commented:  “His ability to create serendipitous harmonies by improvising melodic responses to Coleman’s free-form solos (rather than sticking to predetermined harmonies) was both radical and mesmerizing.  His virtuosity lies . . . in an incredible ability to make the double bass ‘sound out’.  Haden cultivated the instrument’s gravity as no one else in jazz.  He is a master of simplicity which is one of the most difficult things to achieve.”  (More from Wikipedia)