Not surprisingly, much of what’s exciting about Music Update has to do with rhythm. The members of Jason Marsalis’ quartet make rhythmic decisions that enliven ideas throughout, and they often reveal a wit that you might not expect. That sense of humor is evident from the outset; “Guess Who’s Back?” is a solo drum piece that is based on a marching band drum line, and it sets the tone for the album. Marsalis plays vibes for most of the album, turning the drum chair over to David Potter, but drum-only compositions performed by Marsalis filter through the album. Not only do they keep the album from settling too comfortably into one voice, but they’re smartly constructed, multilayered pieces that cleverly riff off their titles. There’s a ghost of disco in “Discipline Spotted Baby and Zutty at Studio 54,” and his work on the bells of his cymbals gives an eastern flavor to “Discipline Vacations in Asia.”

In the ensemble pieces, pianist Austin Johnson defines the songs. His box-step pattern and Potter’s sizzling hi-hat gives a Vegas go-go excitement to “Seven Come Eleven,” and his pseudo-pomp (with little circumstance) and single-note runs make “Ballet Class” seem awkward and real. If he were a more distinctive soloist, he could steal the ensemble pieces from Marsalis, not because of any weakness but because the nature of vibes and the way Marsalis plays them. Vibes don’t demand the listener’s attention and Marsalis examines melody and space effectively, but not dazzlingly. He’s strongest on the melancholy, mood-oriented “Durango Kid.”

Any musician worth hearing is a work in progress, and Music Update suggests that Marsalis knows he’s one. He salutes the other vibes players in town in the liner notes, and he’s clearly finding his voice on the instrument just as his young bandmates are finding theirs. With Music Update, part of the album’s pleasure is at the meta-level—the performed drama of players in development—but you also hear Marsalis’ creative, conceptual voice, which is already sophisticated beyond his years.