Henry Rollins first saw pianist Ahmad Jamal at a jazz club in Los Angeles with Flea. When Jamal started to burn, Flea yelled, “FUCK, YEEEAHHH!!!” at the top of his lungs, causing the band to stop cold as Rollins offered meek apologies on Flea’s behalf. “If you ever get a chance to see Ahmad Jamal, run — do not walk — to that gig,” Rollins says. “He is a master musician. He is staggering.” And there you have it. But as any jazz aficionado will tell you, Jamal, 73, has left a deep imprint on luminaries even as he has tossed aside the label “jazz.” Jamal prefers to call it “American classical music” because he feels the music is too vital for a term that started out as a put-down. Indeed, it is Jamal’s ability to bring an orchestral sensibility to the trio format that lies at the root of his far-reaching influence on the musicians who have followed him.