Fiddler Darol Anger, mandolinist Mike Marshall and bassist Todd Phillips first assembled as three-fifths of the 1979 David Grisman Quintet, the group that set down the recipe for new-acoustic music, bluegrass instruments, folkloric sources, jazzy improvisation and virtuoso picking. Twenty years later, the three are still playing together, this time as half of the new-acoustic super-group, NewGrange, which also includes banjoist Alison Brown, pianist Philip Aaberg and singer Tim O'Brien.

NewGrange used to be known as Heritage, named after the "Heritage" and "Christmas Heritage" albums spearheaded by Anger in 1997 and 1998. On the new, rewarding "NewGrange" album, the sextet becomes more of a democratic effort. O'Brien's vocals and Celtic interests are felt on the original "Music Tree" and the traditional "Handsome Molly." Aaberg's cinematic, new-age melodies are represented on his two compositions. Brown's angular banjo picking is felt throughout, especially on her own brisk tune, "Weetabix."

Anger and Marshall have been doing bizarre things to bluegrass from their early days in the Grisman Quartet through their association in such groups as Montreux and Psychograss. They carry on that tradition in NewGrange by playing the old standard "Sally Ann" fast and loose, by constantly changing meters on Marshall's "Shoot the Moon" and by giving O'Brien's "Land's End" a mandolin quintet arrangement.

Appearing Thursday at the Barns of Wolf Trap.

To hear a free Soundbite from NewGrange, call Post-Haste at 202/334-9000 and press 8103. (Prince William residents, call 690-4110.)