What exactly is Garage a Trois? Jazz fusionists? Jam band improvisers? Moody cinematic instrumentalists? Experimental rockers? Attempts to categorize this musical supergroup are doomed to failure. You’d need a proper tailor to fit them into anything. Simply say they make enticing, sonically complex, and always adventurous music without vocals.

“We’re big fans of the riff. Zeppelin, ZZ Top, Weedeater, Motörhead, Sabbath … we love all that stuff, so we incorporate it,” says saxophonist/multi-instrumentalist Skerik (Critters Buggin, the Dead Kenny Gs). “It sneaks in when you’re writing with this band.”

Garage a Trois began as a trio in 1998 during the recording of Galactic drummer Stanton Moore’s solo debut, All Kooked Out! They released their debut four-track EP, Mysteryfunk, in ’99. The title offered as fine a description of the spooky electronics-abetted, genre-spanning sound inside as any other. Percussionist Mike Dillon joined them on tour and the band expanded to a quartet.

Garage a Trois forged ahead with a variety of keyboardists, including John Medeski and Robert Walter. Marco Benevento finally replaced him.

A Berklee School of Music grad, Benevento had released several albums in a duo with drummer John Russo, who joined him in backing Trey Anastasio’s solo tours. The addition of Benevento changed the quartet, moving them further from jazz and into a more rocking direction.

“There’s a lot of unity when you have four people playing the same riff,” says Skerik. “It’s just a powerful, unifying experience.”

Of course, describing them as a rock act is probably going too far. However, their latest, Always Be Happy, But Stay Evil, is probably their least jazz-oriented release to date. Samples swirl, rhythms strut, and a dark energy commensurates with the album title — from the shadowy, marching machinations of “Resentment Incubator” to the chunky horror-inspired tribal skronk of “Swellage” and the haunted, jazzy minor chord melody “Baby Mama Drama.”

Though he listens primarily to acts with singers, Skerik expresses a great appreciation for the unique connective power of instrumental groups.

“It’s the gilded cage. Lyrics make you commit to one thing and it’s the same thing every night,” he explains. “I like how instrumental music doesn’t tell you how or what to think.”

In his opinion, the improvisational nature of Garage a Trois’ shows gives listeners something very personal and unique.

“By including improvisation in our songs, you can interact with people much more,” Skerik says. “Lyrics are much more like you’re talking at someone, not with them.”

Though Skerik’s appreciative of what music school has to offer, he worries that, particularly in regards to jazz, it produces musicians who spend too much time in their own head.

“You have to define yourself through a variety of activities in the real world, not in theoretical areas or theoretical places,” he says. “You need to be out there really doing it.”

A veteran of at least a dozen different outfits who’s appeared on more than 50 albums, Skerik knows what he’s talking about. But mostly he does Garage a Trois, and lets the music do the talking.