HARDtalk's Stephen Sackur speaks to John Cale, a founding member of the Velvet underground, and a solo artist and producer. In the checkered history of rock and roll, there have been relatively few artists who have managed to create a genuinely new, even revolutionary, sound. The Velvet Underground achieved just that in mid-sixties New York - combining youthful anger, musical creativity, with an avant-garde art sensibility. Today John Cale continues to experiment with new sounds. To many, his music is challenging, even bleak, but is that a reflection of the man himself?