A piano-vibes pairing that revels in its rhythm

The improvising duet may be the most primal form of jazz interaction.

Regardless of the combination -- and there is a seemingly infinite variety of possibilities (from two pianos to two guitars, from saxophone and bass to trumpet and drums) -- the duet’s potential for intimate, mano-a-mano musical exchanges is jazz in its most pristine creative state.

When the duet consists of piano and vibraphone, played by Mulgrew Miller and Steve Nelson, respectively, the prospects for compelling music become even more expansive. On Friday night at the Jazz Bakery, the gifted artists offered a program that was both musically illuminating and rhythmically gripping.

They did so even though the piano and the vibraphone can make for a tonal odd couple. Both are instruments in which sound is produced by impact -- hammer on strings for the piano, mallet on metal bars for the vibraphone. Yet there are vast and subtle differences in the potential each instrument has for shaping that sound.

In this case, the general procedure was for Nelson to take the initial melodic lead, with Miller providing rhythmic flow and harmonic texture.

They opened with standards, “What Is This Thing Called Love?” and “What’s New?,” dispensing quickly with the themes before diving into a whirlpool of improvisation.

Here, as in other pieces, Nelson’s virtuosity was always a driving force, encompassing the music’s flow in waves of rapid notes.

Miller, on the other hand, especially in the more rhythmically gentle settings of “Wave” and “Up Jumped Spring,” took a more contrasted approach, mixing melodic paraphrases with interspersed cascades of arpeggios.

The contrast was amiable and effective, precisely the sort of dissimilarity that makes for the most intriguing sort of duo improvisations.

There were, nonetheless, moments in which one wished to hear more air in the music -- more open spaces between the notes, especially in Nelson’s busy phrases.

There was little else to carp about, however, in this otherwise sterling example of prime duet jazz in action.