FIDDLER Darol Anger and guitarist/mandolinist Mike Marshall are alumni of the David Grisman Quartet, the pioneer in new acoustic music. Keyboardist Barbara Higbie comes out of the women's music movement, and Michael Manring was the house bassist for Windham Hill's new-age stable for several years.

These four musicians have now formed a quartet called Montreux that's too rhythmic to be new age, too male to make women's music and too electric to be new acoustic. What it sounds like more than anything else is a traditional improvising jazz combo with untraditional instrumentation.

With drummer William Kennedy acting as an unofficial fifth member, this quintet swings convincingly on Montreux's first studio album, "Sign Language." All four of the official members are accomplished composers, so each of the album's eight instrumentals (divided with typical democratic equality) begins with a captivating melodic figure that is picked up and passed around with increasing velocity by the four improvisers.

No matter if the original theme has a pop-rock, Caribbean, country, cabaret or pulse-music feel originally, the ensemble spirit of improvising transforms every piece, and the album preserves Montreux's distinctive and consistent sound.

Anger, Marshall and Manring all make guest appearances on "Acoustic Spirit," the first American album by guitarist Peppino D'Agostino, the Italian equivalent of Pierre Bensusan. Mixing classical and folk techniques like his heroes Bert Jansch and Robbie Basho, D'Agostino is an imposing performer capable of one-man guitar duets. The best parts of the album are his original pastoral instrumentals on unaccompanied guitar. Less successful are his mushily romantic singing and his similarly syrupy use of synths.

MONTREUX -- "Sign Language" (Windham Hill WH-1058).

PEPPINO D'AGOSTINO -- "Acoustic Spirit" (Shanachie 96002).

Both appearing Saturday at the Barns of Wolf Trap.