GUITAR PRIMERS are forever telling aspiring musicians that knowledge of a few chords will unlock the pleasures of acoustic music. Anyone acquainted with strum-and-hum folk music knows better. What's more tiresome than hearing one song ater another chained to the same plodding progression?

Fortunately, a new generation of acoustic guitarists has evolved in recent years. Like Charlie Byrd and other jazz or classically trained guitarists, they approach the fretboard as if it were a keyboard, aware of its complexity and potential. New releases by Guy Van Duser, Tony Rice and Pierre Bensusan illustrate just how refreshing, imaginative and diverse this music can be.

Van Duser's "Raisin' the Rent" (Rounder 3071), for instance, is a finger-popping joy from start to finish. As in the past, the guitarist shares equal billing and playing time with clarinetist Billy Novick on an ingratiating collection of Tin Pan Alley, ragtime and jazz tunes. For the most part, the songs are performed with the originals in mind; at least they succeed in capturing the flavor of the era they represent.

Occasionally Van Duser and Novick trade vocals, sometimes crooning earnestly, more often tossing out the lyrics in an offhanded, humorous manner reminiscent of Fats Waller's delivery. But the backbone of this album is clearly the instrumental blend, the intricate yet decidedly uncluttered arrangements that allow the sound of guitar and clarinet to flow so naturally.

Van Duser is a wonderfully nimble finger-picking stylist. He constantly fashions delicate yet swinging solos, graceful contrapuntal lines and the fat chords responsible for the buoyant pulse that underlines so much of the music. Though he's plenty fast, he's not a flashy guitarist; his touch is sharp, precise and always logical.

His playing also beautifully complements Novick's luscious tones and melodic arabesques. Throughout the album Van Duser tethers Novick's flights and twisting modulations, abetted by the tasteful drumming of Bob Jackson and the equally subtle support of bassist Brian Torff. Together, these musicians have produced an album of acoustic music that swings with an irresistible verve and congeniality.

A more progressive, complex and textured sound is heard on "Backwaters" (Rounder 0167), by the Tony Rice Unit. Since leaving the David Grisman Quintet several years ago, Rice has issued a number of ambitious string band recordings. Like the rest, "Backwaters" places Rice's swiftly articulate flat-picking against a backdrop of shifting ensemble passages, in which bass, rhythm guitar, mandolin and violin are prominently featured. The setting, detailed as it is, allows for plenty of improvisation, and much of it is beautifully executed, especially on the jazz-inspired "My Favorite Things" and "On Green Dolphin Street." The latter is a showcase not only for Rice, who plays with exceptional agility, but for violinists Richard Greene and Fred Carpenter, who take turns enlivening the melody.

The challenge Rice faces on every album is avoiding the sameness of tone inherent in string-band recordings. "Backwaters" overcomes this problem handily, thanks to a variety of sprightly arrangements, resourceful ensemble playing and Rice's own formidable skills as an improviser.

Pierre Bensusan is a young French folk musician whose influences are many. They include contemporary guitarists John Renbourn and Stefan Grossman, jazz stylists Lenny Breau and John McLaughlin, and various elements of Irish, Oriental, Arabic and, of course, French traditional music. On "Solilai" (Rounder 3068) the mood is decidedly French, but the romantic themes are really incidental to the rich tone Bensusan extracts from his guitar.

The guitar sings in Bensusan's hands. He plays without a pick, with a sharp attack and a deft manner of turning a phrase. Unlike many of his principal influences, he doesn't compose striking guitar pieces that can stand alone, but his melodies nevertheless sparkle and are enhanced by additional instrumentation. His eclectic repertoire, firm intonation and gentle lyricism make for one of the more enjoyable listening experiences in folk music today.

In all likelihood these albums will attract different audiences. But each in contributes to the diversity of acoustic music with taste and imagination.