Rhythmic experimentation, melodic repetition and oddball spontaneity are at the heart of the music made by Atlanta-based singer, guitarist and bandleader Col. Bruce Hampton. Whether through songcraft and arranging or on-the-spot improvisation, getting weird while maintaining the groove has long been Hampton’s main goal.

With the Aquarium Rescue Unit, one of several notorious projects helmed by the Colonel over his four-decade career, rhythmic exploration has always been key, from the quartet's earliest days in the Atlanta and Athens club scenes of the late 1980s and early 1990s to their latest reunion tour.

"You have to have a groove or you're not going to eat," says Hampton. "After that, do what you want to do… A groove with drums and bass is necessary, because people want to attach themselves to it, but on top, paint something and go into outer space."

Having been established as a bluesy rock guitarist during his years with the Hampton Grease Band (in the late ‘60s and '70s) and the Late Bronze Age (in the ‘80s), Hampton formed the Aquarium Rescue Unit in 1989. In 1991, the band released its debut on the Georgia-based Capricorn label: a self-titled concert album recorded at the Georgia Theatre. The 12-song set captured the band's raw, quick-tempo, Southern-tinged spazz-outs.

You have to have a groove or you're not going to eat.

"Most people used to just sit there, baffled," Hampton says of the band's early performances. "But… there was always a song, even in the madness. We basically did one song, and we did it all night. We still do."

With bassist Oteil Burbridge, guitarist Jimmy Herring and drummer Jeff Sipe—three veterans from the earliest versions of the Unit—on board alongside keyboardist Matt Slocum, the band reunited earlier this summer for a tour of Colorado, the Southeast and New York. It's the group’s first major string of shows since a brief reunion in 2007.

There's no shortage of talent or expertise in the Unit’s impressive lineup; each member has collaborated with a variety of artists in the jam band, jazz fusion and roots music scenes over the years. Burbridge is best known for laying down bass lines with the Allman Brothers Band and the Tedeschi Trucks Band. Herring is a familiar and admired figure, most recently for his work with Athens' own Widespread Panic.

Sipe (aka Apt. Q-258) has fronted his own bands (Zambiland Orchestra, in particular) and recorded and toured with Béla Fleck, Phil Lesh, Trey Anastasio and Leftover Salmon. Slocum, a favorite cousin-member of the Unit, has plunked notes with Hampton in the Code Talkers, performed with Burbridge in Oteil and the Peacemakers and collaborated with Susan Tedeschi, among others.

“Those guys are the best in the world on their instruments, so that helps,” Hampton says with a laugh. "Everything's chemistry, and we're lucky that we have it. We've always had it, and we hope that it's there every night. We played for years and never had a rehearsal, and I think we only had one really bad gig in 10 years. We have ups and downs like everything and everybody, but we just let it go.”

Last week, the Unit performed four shows in Colorado. The band will hit 10 more stages throughout August, including the Buckhead Theatre in Atlanta on Aug. 7 and the Georgia Theatre on Aug. 8. Hampton and company plan to document most of their summer tour and release a live album later this year.

"I dig ‘live,’” says Hampton, who cites B.B. King's Live at the Regal, John Coltrane's Live in Seattle and John Lee Hooker's House of the Blues as some of his all-time favorite concert albums. "I dig the approach of ‘just do it’ with no overdubs… Just do it, and whatever's on there is the truth. And don't lie to me; let me hear what you got.' There's beauty in everything—the good, bad and ugly."

The band's summer setlists should feature plenty of classic tunes from Hampton's early days, the Unit's heyday and even a few new compositions.

"We're playing some tunes that I've been doing since the '60s," Hampton says. "We just can't let them go. They seem to work. It's always a surprise what happens onstage. Sometimes we fall flat on our face, and sometimes we soar. Either way, it's fine with us. If we fall flat, then we think we're gonna rescue ourselves and recover. Sometimes we don't, but it's still wonderful."

WHO: Col. Bruce Hampton and the Aquarium Rescue Unit
WHERE: Georgia Theatre
WHEN: Saturday, Aug. 8, 8 p.m.
HOW MUCH: $25