The band was warming up when the lead singer arrived at a Midtown studio shortly after 4 p.m. Monday.

He dropped his briefcase, practically sprinted to the microphone stand at the front of the room, and began tapping away at a red tambourine. He wore a fedora.

“Let’s take it from the fiddle solo,” he said.

The music career of James L. Dolan has been the source of mild fascination for people who are far more familiar with his positions as the president and chief executive of Cablevision and the owner of the Knicks and the Rangers.

Critics have not always been charitable. But with his band, JD & the Straight Shot, releasing an album this month, Dolan has been back in the studio to prepare for a series of concerts, including one that was scheduled for Saturday night at Madison Square Garden, a building he owns, as the opening act for the Eagles.