Trumpeter/composer Dan Rosenboom has knocked around L.A. for nearly two decades, playing sessions, writing scores, and leading his own bands. As the 101st release on his own Orenda label, Polarity serves to both sum up and advance his career thus far. Working with a crack band – saxophonist Gavin Templeton, keyboardist John Escreet, bassist Billy Mohler, drummer Damion Reid – and producer Justin Stanley, Rosenbloom presents a range of postbop compositions and improvisations. Rosenboom tends to write melodies that don’t immediately shake hands, but don’t push people away, either – which makes them perfect for this batch of musicians. Both sensitive players, Mohler and Templeton provide the requisite jazz grounding, allowing Reid and especially Escreet to ride off the rails whenever they choose without knocking the center off keel. The leader reads the room with great expertise, equally able to keep up with (or contrast) the chaos and support the balance. That’s what makes a good bandleader, and that’s what puts composed tracks like “Walking Shadows” and “War Money” on equal footing with group improvisations “Tidal Mirror” and the twenty-minute “The Age of Snakes.” If Polarity is your first Rosenboom experience, it’ll likely send you scrambling through his back catalog to find what will no doubt be a plentiful number of further gems.