Magma: Not prog, but certainly progressive, and flowing here Wednesday

When the famed Parisian ensemble Magma plays Underground Arts on Wednesday, the musicians will hit the stage with every slithering, outre hallmark that drummer-composer-leader Christian Vander first adopted in 1970:

A devised language with an interplanetary mythology dedicated to a doomed Earth and settlers on the imaginary planet Kobaïa; a psychedelicized, free jazz, fusion-electronic tone with complex rhythms that Vander calls "Zeuhl" for its "vibratory" qualities; chanted vocals; and occasional diabolical artwork by industrial surrealist H.R. Giger.

All these things speak to - and reek of - prog-rock, that bloated-but-intriguing brand of orchestrated rock perpetrated (for better or worse) by the likes of Emerson, Lake & Palmer, Yes, King Crimson, and Genesis.

Magma, too, was tagged with being both avatar and follower of prog-rock, a notion that never pleased Vander. "It is definitely not a subset of prog and Magma isn't a prog group," he says in an interview from Chicago. "Magma is an institution, the ultimate in terms of musical skills and also in the way a musician has to dedicate his life to music."

That aesthetic is what first attracted Magma vocalist Stella Vander, Christian's former wife, to the band.

"As a kid, I had a kind-of career of my own, hit songs at 13 years old when I did my first EP," says Stella Vander. As Stella, she released '60s Yé-yé pop parodies and folk scene disses "Pourquoi pas moi" and "Beatniks D'Occasion" between 1963 and 1966. "I was successful but somehow knew that wasn't what I wanted to make. I was looking for something."

She found it at 16, when she caught Vander on stage at a Paris nightclub and knew "that something could happen - that this was the music I wanted to do." Stella did lights for Magma's awesome stage shows (still their songs' most powerful presentations, as shown in the recently released, 12-CD live history, Kohnzert Zund). Vander crafted his imaginary language and electric Carl Orffian freak-outs on her piano.

"I witnessed incredible things, saw him compose tunes for the first Magma album at my house, and, as he played, it was if someone was speaking through him," Stella says.

In tongues?

"Yes. The words were coming out, fitting with the music, and told the story of people who wanted to escape from Earth and go to Kobaïa. He didn't want to say it in French because that language wasn't strong enough, or in English because his grasp wasn't there. So he made something up."

That vexing sound and vision filled so much of Magma's best, heralded work, including 1973's Mëkanïk Dëstruktï? Kömmandöh ("still my favorite" says Stella), 1974's Köhntarkösz and 1978's Attahk with its Giger cover art.

Magma, however, didn't break in the same fashion as, say, Genesis or ELP - first, because the Parisians didn't fit the prog tag, nor did they want to. "We didn't think it fits or suited us," says Stella Vander. "Not that there's anything wrong with it. You can find very good, very bad, and not very interesting bands under that tag. It's just not us, even though people say we were the very beginning of the movement."

She also believes a lack of solid management, especially in America, is the reason Magma never broke beyond its circle of devotees - until now.

Stella says that between new management and young social-media influencers, there is a demand for Magma in the U.S. that their current tour seeks to satiate. Also likely to satisfy audiences is the opening act, classically trained "doom cellist" Helen Money (real name Alison Chesley).

The new music that Magma has recorded in the last several years also should prove popular with audiences. It's classic, progressive Magma yet with bright, bold twists on the monstrous sound.

"While Ëmëhntëhtt-Ré is very much us," she says of the cosmic 2009 album, "2012's Félicité Thösz shows off a softer side of Magma, something happier and more serene. Then there is the sound of 2015's Slag Tanz that is dense and heavier, a direction I believe Christian would like to continue for now."

Christian Vander portrays Magma's bleak, hard new music as a cinematic continuum of his earlier ecological work. "Alas, with time and in light of world events, I have a vision of man becoming darker. There is hope, however. It is likely man will self-destruct, which would be a boon for all the species populating the known and unknown universe."

Magma and Helen Money, 9 p.m. Wednesday, at Underground Arts, 1200 Callowhill St. $25. undergroundarts.org.