STS9 doesn't just defy boundaries, it transcends them with its brand of electronic dance music. See the band at the Showbox Feb. 20 and 21.

An instrumental quintet from Santa Cruz, Calif., STS9 makes electronic dance music, the kind usually created by furtive producers alone in bedroom studios and played by party-starting DJs at sweaty all-night raves: feverish drum ‘n’ bass; melodic trip-hop; glitchy laptop techno; throbbing, bass-heavy dub. The band is unafraid to drastically alter its sound with each album, trading out fans in the pursuit of new musical ideas.

Thanks to this shifting relationship between band, fans and source material, STS9 (shorthand for Sound Tribe Sector 9, a new-agey moniker the band now eschews) is a barometer for electronic dance music. When electronic dance music is healthy — when it’s accessible rather than alienating, when it refines rather than splinters — STS9 is healthy. When it flows into esotericism, STS9 loses steam. This has been the case since early in the decade, when the band migrated to the West Coast from Atlanta and transitioned from a funk-inflected improv band to something far deeper and more complex.

If the barometer analogy is accurate, everybody’s feeling really good right now.

Visionary producers like Flying Lotus, Mike Slott, Four Tet and Hudson Mohawke represent today’s most exciting development in music, electronic or otherwise. (If you’re unfamiliar, Google those names ASAP.) Their finely sculpted cosmic beat symphonies are STS9’s current touchstone, evidenced by “Ad Explorata,” the band’s fifth album, released in December on its own 1320 Records.

“Ad Explorata” in Latin, roughly “forward into the unexplored” — is stunning; STS9’s most invigorated and invigorating work in years, potent and polished and focused, clever and rugged and sometimes beautiful. This is experimental, rhythmophilic music, soulful like jazz, headstrong like rock, unique in its tone and palette. The phrase “orgasmic soundscapes” comes to mind but won’t be used here.

And so the question that most often arises around STS9 is: Why? Why a five-piece band that mimics what a single producer or DJ does?

STS9 answers on stage. A typical concert is a collective multimedia celebration. Musically, and among the crowd, genre is transcended: Audiences are a disparate, rabid cohort of ravers, hippies, hip-hop fans, fans of improvisational music. The light show is James Cameronian in scale and execution. Usually a performance painter works during the show — former Seattleite J Garcia, for instance, whose richly detailed canvases sell for thousands of dollars.

The band has also hosted fire dancers, a poet typing on a battered Smith-Corona and a performance flower arranger. Maybe the band’s lyricless format allows deeper immersion into the music; maybe the drugs are really strong.

Either way, it’s a unique, enthralling experience. And a popular one: STS9 consistently ranks as one of America’s top-50-grossing touring bands, according to Pollstar magazine, selling out mid-sized venues across the country — like the Showbox at the Market, where it plays two all-ages shows this weekend. They’ve carved out a viable niche as artists — modest, self-governed, community-oriented, durable — proof that in a faltering industry, originality and execution go a long way.

Jonathan Zwickel: zwickelicious@gmail.com