Andrew Limbong

Bobby Hutcherson, a vibraphonist whose improvising and composition helped to define modernity for jazz as a whole, has died. He had long struggled with emphysema. He was 75.

As a mallet percussionist, he expanded the scope of what was possible on his instrument. And the sound he created was widely influential.

Paul Bley, a jazz pianist whose thoughtful but intuitive commitment to advanced improvisation became widely influential, died of natural causes Sunday. He was 83.

Bley was surrounded by family at his winter residence in Stuart, Fla., according to his daughter Vanessa Bley.