A curious paradox appears to be at work among the folkies and singer/songwriters whose highly personal songs and interpretations set the tone for the late '60s and early '70s. As their faces have become more creased with character won of age and experience, their music has tended to grow more distant, smoother and less personal. Willie Nelson withdrew to Tin Pan Alley, Dylan to heaven, Joni Mitchell to jazz.

With the exception of the McGarrigle sisters, these mellowed troubadors seem to be studiously avoiding the deeply confessional style that brought them to the forefront of American music. And while that may not be a bad development in itself (how long, after all, before the poetically personal becomes merely solipsistic?), it has the strange effect of stripping the music of some of its power.

Tom Rush not only laid the groundwork for what became the definitive and much- copied folk/rock style, he discovered many of its practitioners in his own quest for material suited to his warm, wayward voice and his yearning, deeply felt interpretive style. On "New Year," a celebration of his twenty years in music recorded live at Boston's Symphony Hall, his voice no longer encompasses the pain or the introspection of his early work. He's no longer singing about himself on old favorites like "Drivin' Wheel" or "Merrimack County," but about a Protagonist kept at arm's length by the stories he weaves.

Rush's emotional distance can be measured by both what's included on "New Year" and what's left out. Conspicuously absent is the raunchy "Who Do You Love," which established him in the early '70s as a rocker as well as a thinker. But a comparison of the latest rendition of "Urge for Going" with the version on his groundbreaking '60s album, "The Circle Game," is truly striking. Rush picked up this Joni Mitchell tune when he was a bored Harvard student bumming around the Boho Zone, and he must have picked up a few of her poetic coffee-house mannerisms as well, since he invested it with such want and wistfulness it became something of a hit for him. On this recording, all that's left of Mitchell's influence is the phrasing, and what's left of Rush is precious little indeed.

Rush's voice on "New Year" is calm, predictable, "mature" in the most disappointing way. But it must be said that he has tried to fill the emotional gap by bringing together a most tasteful and sensitive backup crew. Joshua Shneider's sax on "Drivin' Wheel," Irwin Fisch's keyboards on "Kind, Kind Lovin' " and "Wasn't That a Mighty Storm," Marshal Rosenberg's percussion all over the place and David Buskin and Robin Batteau's backing vocals -- all make a valiant effort to bring the innocent old Tom Rush back up to the level of the sagacious young one. TOM RUSH -- "New Year" (Night Light HS-28011). Appearing Friday through Sunday at Charlie's Georgetown.