In a genre dependent on interaction, changing only one member of a group can yield significantly different results. For Voices, the second in his New York Trio Recordings trilogy, pianist Marc Copland retains bassist Gary Peacock from Modinha (Pirouet, 2006), but replaces Bill Stewart with enduring percussive colorist Paul Motian. The result is an album that finds Copland—a relative latecomer to his instrument, but whose voice is as dependent on his unmistakable harmonic language as it is on his elegant touch—at another career high point. If an award existed for consistency and slow but palpable evolution, Copland would undoubtedly be on the shortlist. He's yet to release anything less than superb, while creating the kind of contextual diversity that makes every record worth checking out.

With Stewart's melodic but more direct approach, there were some serious sparks on Modinha, a surprisingly outgoing recording for the normally introspective Copland. Voices has its own power, but relies even more deeply on the concept of relationship: Peacock and Motian have worked together for some forty years, while Copland and Peacock go back to the pianist's At Night (Sunnyside, 1991). The bassist's dark-hued "Vignette," which opens this recording of largely original material, was first heard on Copland's duet recording with Peacock, What It Says (Sketch, 2004). Here, with Motian skirting the line between texture and time, it sounds like the ECM recording that Copland's never made.

The trio swings, but in the most flexible way, on Peacock's "Albert." Peacock and Motian occasionally lock into a clear groove, but keep all options open, as responsive and conversational as ever during Copland's solo. The collective simpatico is all the more remarkable given that this is the first encounter between Copland and Motian. Peacock's "That's It?" enters freer territory, a brief motif giving way to more open-ended exploration, and featuring a brief but beautifully constructed solo by Motian.

Copland revisits his own altered and impressionistic blues, "River's Run," from the outstanding solo album Time Within Time (Hatology, 2005). It's easy to think that a solo reading provides more inherent freedom, but it's the beauty and strength of this trio to approach time like a house of cards—where each player's contribution adds to the ultimate forward motion, but no individual voice defines it.

Even when the trio tackles Miles Davis' enduring "All Blues"—with Peacock's sharp tone contrasting Paul Chambers' earthy warmth and Motian's in-and-out pulse a modernistic alternative to the straightforward approach of Jimmy Cobb—it finds a place where mainstream and experimental meet. Bill Evans may be an undeniable influence, but Copland's oblique lyricism is both contemporary and deeply personal.

It's perhaps Copland's greatest strength that, no matter how challenging his harmonic language is, his music remains eminently accessible. For those in the know, Voices is yet another milestone in his steadily building discography. For the uninitiated, it's a good place to start for an American pianist who remains sadly underappreciated in his own country.