Dennis Irwin died at 3:30 yesterday afternoon. Four hours later, in the Allen Room at Jazz at Lincoln Center, Joe Lovano's band led off what was to have been a benefit concert. Like Dennis, Lovano's bassist Cameron Brown is white-haired and medium height -- a detail you notice with bassists. I wanted to believe he was Dennis. Wynton Marsalis spoke of Dennis's "most magnificent attitude." The rest of the night spoke to his most magnificent music. Among the moments, Bill Frisell's phrases and spaces evoking "I'm So Lonesome I Could Cry," and Harry Allen and Joe Cohn's simple sax / guitar duo of "Body and Soul." David Berger told the story of Dennis coming to BAM to sub in the Harlem Nutcracker, a complicated, fast-paced score which Dennis virtually sightread. At the end of the first act, the band spontaneously gave the bassist a standing ovation. Dennis stayed in David's band for the next 11 years. Adorable in a tiny dress and high high heels, Aria Hendricks -- Dennis's love -- sang with her father Jon on "Doodlin'". Jon sang air bass on his solo.