Those bad boys of Bethesda, the Nighthawks, return to the Bayou this weekend, not only with a live stage show but with a live concert album recorded at the Georgetown nightclub in the waning nights of 1981.

The menu then and now: high-energy rock'n'roll solidly grounded in the hard-edged urban blues of Chicago. It's an impeccable sound that the Nighthawks have mastered by playing 300 nights a year, mostly on the road. The selfproduced "Ten Years Live," to be followed soon by a two-record retrospective on Adelphi, shows clearly why this rough-hewn quartet has been a consistent winner in performance and a consistent loser on vinyl.

This time, the fault can be spread evenly between the Nighthawks' habitually weak vocals and their decision to record all original material. Live, the gruff, ragged vocals have always been obscured by the group's pile-driving instrumental prowess, particularly Jimmy Thackery's ecstatic, ear-popping guitar and Mark Wenner's razor-sharp harp; both shine on "Ten Years Live" but only when they let their instruments take over.

Like many blues-based bands, the Nighthawks have traditionally chosen better material than they've been able to write. The songs, on "Ten Years Live," unguarded by choice covers, sound like borrowed, or absorbed, homage rather than statements. "Jenny Lou" is kicky rockabilly, while "Moving Up In Class" and "Backstabbing Woman" are classic Chicago-style blues; "Metropolitan Avenue/ Guard Your Heart" evolves out of a funky, Allman Brothers-style shuffle. The plaintive "If You Go," the album's best cut, deserves to be covered by Eric Clapton. It's al competent and a good frame for the group's powerhouse solos; ultimately, though, "Ten Years Live" is another holding action, a step not backwards, but sideways. THE ALBUM: 'Ten Years Live' (Chesapeake CR-LP101) THE SHOW: 8 and 11 Sunday and Monday at the Bayou.