“What do you call a trombonist with a pager?” goes the old joke. “An optimist.”  Trombonist and master educator Hal Crook joined the Berklee faculty in 1986 when pagers were still a thing, having himself graduated from the school a decade earlier. On Thursday night the college celebrated his announced retirement with a sold-out, star-studded concert at Berklee Performance Center.  Joining Crook for the evening’s first set was an advertised crew of big-name Berklee alumni whose paths had crossed Crook’s: Esperanza Spalding on upright bass and vocals, her frequent collaborator Leo Genovese on piano, Chris Cheek on tenor sax, and Lionel Loueke on guitar. Drummer Antonio Sanchez, fresh from a Grammy win for his “Birdman” score earlier in the week, was a late addition to the lineup.  They opened by stretching out on Crook’s “Set Me Free,” whose title was the event’s theme and whose structure interspersed restatements of the melody — Spalding’s wordless vocals acting like a third horn — with bouts of free soloing by everyone save Sanchez. Crook didn’t solo much through the night; when he did, his trombone had a trumpet-like brightness as he demonstrated that he can very much keep pace with the famous acolytes surrounding him.  The opening set ended on another highlight, “Domestic Violets,” a Crook bouquet for a pet cause: a shelter for victims of domestic violence. Spalding, who introduced and sang it, said, “We’d like to dedicate this to anyone with a bruise or a cut or a busted lip.”  Crook entertained the audience during an intermission, blowing “For He’s a Jolly Good Fellow” on a kazoo, reminiscing, and cutting up. (One joke mined the pager vein: “Soon I’ll be a retired trombonist. I know a lot of you are thinking, ‘What’s the difference?’ ”) Then he brought out his band Behind These Eyes for a set of jazz-inflected pop featuring the ebullient vocals of Berklee alumna Deborah Pierre, Wesley Wirth’s electric bass (his solo on “What Is Going On” a particular crowd-pleaser), three keyboards, drums, and a tight four-piece horn section.  Crook, who wrote the band’s music and lyrics, skipped soloing the second set. Nor did he solo on the night’s final number — but most everyone else did when the first set’s stars joined Behind These Eyes for “Hide and Seek,” Cheek switching to soprano sax, Genovese launching his piano solo into orbit with palms and forearms. Then Crook, confirming his optimism, reminded the audience that “Life is the greatest prize” as he bid them adieu.  The Music of Hal Crook: Set Me Free  At Berklee Performance Center, Thursday
On Thursday at the Berklee Performance Center, trombonist and pedagogue Hal Crook played a farewell concert featuring some of his now-famous students.