by Brian KellyDouble Time may be among Bela Fleck's least ambitious solo projects, although it proves an easily digestible introduction to his wildly eclectic banjo forays. After all, Fleck is a true pioneer of the five-string, an artist who has not only pushed the stylistic bounds of the instrument itself, but also established it as a stage centerpiece with his effortless rolls, subtle use of harmonics, and single-string runs. Suffice it to say, this 13-track compilation of acoustic duets features all of the above -- and in abundance. Fleck is the lone constant; the rotating cast he enlists is the variable that leads him into untrodden turf on each successive track. Perhaps the album's greatest strength is the ever-morphing musical landscape in which Fleck so easily adapts. The billing includes Mark O'Connor, Sam Bush, David Grisman, Pat Flynn, Tony Rice, and Jerry Douglas, among others. So, would this make Double Time a straight bluegrass album? Well, not exactly. Despite his relative newcomer status at the time of the recording, Fleck was already well-entrenched in jazzgrass explorations. As a result, Double Time nearly evades categorization. Two of the selections are particularly unconventional: "Lowdown," a plodding, walk of a tune -- featuring the unique bowed bass work of Edgar Meyer -- which builds to a frenzied crescendo, and "Light Speed," a spacy, improvisational jam recorded at half speed with Mike Marshall on octave mandolin. Otherwise, the program features a dozen or so warm, homegrown finger exercises that dot the music map everywhere between bluegrass and jazz fusion. If you happen to prefer a less adulterated Fleck, you won't be disappointed. If you're interested in discovering new pickers, Double Time is a ten-point intersection.