The New Sound Quartet, also known as the Joe Locke/Geoffrey Keezer Quartet, is a powerhouse of a group. Since both musicians had independent, well-established careers before teaming up, their names vie for top billing. But this quartet, by any name, is still one of the finest exponents of hard- and post-bop jazz currently playing. And they are in Japan for a week-long tour this week.

On vibraphone, Locke is a worthy successor to past vibe masters Bobby Hutcherson and Milt Jackson. His releases over the past two decades, first as a sideman, then as leader, showcase his talent for playing with both lyrical beauty and incredible speed. Keezer, younger by a decade or so, was a piano prodigy who joined Art Blakey's famed Jazz Messengers at the tender age of 17. Since then he has released 10 CDs in as many years.

The unique combination of vibraphone and piano creates a space much larger than the sum of its parts -- one in which these two brilliant improvisers and clever accompanists can really get down to work. When Locke lays down the full, ringing tones of his vibraphone, Keezer takes off at full throttle; and when Keezer's sophisticated spatial sense launches chords, Locke works his four mallets with fiery skill. Even when navigating tricky chord progressions at rocket speeds, they never lose their deep sense of swing.