"Miracles--The Unsung Stephen Sondheim" is the best offering to date from the Off the Circle Theater Company, which has been putting young performers and show tunes together for a year and a half now. Although the format hasn't changed all that much--essentially, the company's little revues are no more and no less than staged concerts--director Frederic Lee has upped the stakes this time. The new show, at d.c. space through Oct. 29, has a satisfying fullness that was often lacking in the past.

The cast has been expanded to seven singers, all of them in fine voice, and to the normally adroit piano accompaniment of Rob Bowman have been added the services of a percussionist. More to the point, Lee is no longer content simply to string together one solo number after another, like beads. "Miracles" mixes and matches its performers, combining them in duets and trios, and even finds moments when all seven can sing at full tilt.

The two hours' worth of songs are divided into three acts, each devoted to a particular Sondheim musical: "Anyone Can Whistle," a 1964 flop; "Pacific Overtures," an esoteric 1976 effort that examined the impact of Commodore Perry's opening of Japan from the point of view of the Japanese; and that lavish, slightly backhanded 1971 tribute to the "Follies." Excepting "Follies," which enjoyed a significant run, the other shows do indeed go largely "unsung" these days.

With "Pacific Overtures," it's easy to understand why. The music in that show is imbedded in a Kabuki-like pageant and is virtually inseparable from the overall story of feudal Japan being ushered, despite itself, into the modern age. The cast, dressed in kimonos, sings 11 numbers from the show, and while you're unlikely to go away humming any of them, they really are deft little playlets, rich in character, drama and imagery. Although a little more narrative material might help to situate the songs in their context, this mini-reprise will still remind you how innovative "Pacific Overtures" was.

The songs from "Anyone Can Whistle" are far more immediate in their appeal. The full company singing "Miracle Song" gets the evening off to a hallelujah high. Ann Johnson brings a splendid mix of brass and swagger to "There's a Parade in Town" and the pure operatic fervor of "With So Little to Be Sure of" is richly embraced by Felicia Imre Colvin and Michael Muziko. (Muziko, especially, has an effortless tenor voice that throws off thrills as well as the high notes.)

It is the "Follies" segment, however, that is the flashiest by far. (Sondheim is our most dazzling lyricist and when he puts his mind to it, he can compose with as much pizazz as the best of them.) Gregory Ford does his usual strut to "Broadway Baby," but with considerably more aplomb than he has manifested in previous outings. Wayne Anderson scores with the tongue-tripping patter of "Buddy's Blues," and Pam Bierly, who has a lot of the virtues of a young Shirley MacLaine, plus a belter's style, raises the roof with a sly, sassy rendition of "I'm Still Here."

Fine as the individual contributions are, it is Lee's willingness to pool the performers' resources that makes the difference. The show is never so infectious as when all seven team up for simultaneous renditions of "You're Gonna Love Tomorrow" and "Love Will See Us Through." The stage may be small, but the sound pouring off it is big and the collective enthusiasm even bigger.