Before producer David Foster completed their transformation into pop stars, Chicago had built an early reputation as a tough jazz-rocking outfit. Peter Cetera was just one of their vocalists, rather than the honey-sweet ballad-singing frontman. He actually played bass. Robert Lamm, one of Chicago's other prominent singer-songwriters, served as principal pianist. Foster changed all of that, beginning with 1982's Chicago 16. "I get it — I get why they were unhappy," Foster tells the Los Angeles Times. "I just came in like a young, arrogant barnstormer: 'OK, I'm playing all the piano now,' and Peter let me play the synth-bass...