These ''grooves'' provided a common foundation upon which an entire community could interact and partake in one grand conversation through music, song and dance -- each adding his or her own improvised part to the living composition. The height of this experience is the trance, a state of complete spiritual channeling -- an idea that is catching on more and more in American music today, whether through ''jam bands,'' drum and bass, electronica or club music.

Tonight, Club d'Elf brings an all-star cast of musicians from around the world to the Georgia Theatre for just this kind of conversation.

Assembled by bassist Mike Rivard, Club d'Elf features John Medeski (Medeski, Martin and Wood) on keyboard; Reeves Gabrels (David Bowie's guitarist for 15 years) on electric guitar; Brahim Fribgane (Peter Gabriel, Morphine, Hassan Hakmoun) on oud (a Middle Eastern lute) and various Moroccan percussion; Mat Maneri (Matthew Shipp, William Parker, Cecil Taylor) on electric violin; Mister Rourke (Soulive, Billy Martin of MMW, Miracle Orchestra) on turntables; and Eric Kalb (Deep Banana Blackout, John Scofield) on drums to heighten and intensify the unit's traveling jazz-trance experience.

The music is inspired by Rivard's study of Moroccan music, particularly the original trance music of the Gnawa. The essence of Gnawa music is the bass groove of the guimbri or scintir (a two- or three-stringed bass instrument thought to be one of the earliest ancestors of the guitar) coupled with the rhythms of the kirkaba (a set of hand cymbals). Instead of beginning with a melody or harmonic structure, as in most Western music, the Gnawa start with a rhythm and all else is layered on top. Using a repetitive rhythm as a foundation makes the music very accessible for participation, as it is easy to catch on and almost any melody can fit over top.

Playing this way is one thing when the group of musicians is sitting in a room for 14 hours and time is irrelevant. Putting something like this together on stage is quite another.

To manage this, Rivard takes a cue from Miles Davis' approach on projects like On the Corner. Davis had a stage full of musicians, and he served as a sort of mixer. Each instrument a fader on a soundboard, Davis would bring in and out certain textures and combinations ''composing'' on the spot.

''Sometimes the musicians haven't played together before,'' explains Rivard of the diverse, rotating line-up, ''but as long as it's together from the rhythm perspective, everyone else can catch on. The musicians that I'm using are just phenomenal improvisers and they have incredible ears, so it doesn't matter if they've heard something before. Once they hear it, it's spontaneous composition. We use the song structure like Miles did in the '70s. Themes come up, but the idea is to develop a group voice and go into group improvisation. Every night we play music that has never been played before.''

Rivard hopes that not only the musicians will be a part of the dialogue, but the audience as well.

''The response has been great because we're all having a great time. It's so obvious that we're doing it because we love the music and we love playing with each other. I think people really pick up on that.''

Club d'Elf played recently in Boston with a Senegalese drummer. ''The opportunity to put the Senegalese thing together with the Moroccan thing was so cool. Everybody was feeling it that night. It's an incredible feeling when the musicians and the audience are communicating on that level and egos are checked. It's a very special feeling.''

-Julie Powell