Musicians are trained — tirelessly, feverishly — to keep audiences awake.

Not in the new Bowerbird concert series Liminal States, seven streamed events slotted at 10 or 11 p.m. that aim to put listeners into a sort-of slumber somewhere between sleeping and waking. The series is co-produced with West Philly’s Rotunda, Bowerbird’s home venue.

“Everybody is so traumatized and beat up that if a concert involves another state of awareness, that’s a very attractive prospect,” said pianist Marilyn Nonken, who opens the series Wednesday with Morton Feldman’s spare, meditative, 90-minute Triadic Memories. “It’s not a piece so much as it’s an environment, a sanctuary, where you can go and stay a while ... The piece does have peaks and valleys but ... you’re not following a story of conflict and resolve. It’s physically different place ... where your brain waves change.”

If the other Liminal musicians have anything in common it’s a concept of sound that proceeds without a predictable end in sight.

The hard-to-categorize indy artists include Jeff Zeigler (Jan. 31), next on the schedule after Nonken, an engineer and producer whose own music falls in the ambient zone. Philadelphia-born Laraaji (Feb. 14), the series’ third performer, is described as often as a mystic as he is a percussionist who creates shimmering, luminous sound environments.

Laura Baird (Feb. 25) arises more from the folk tradition but crosses over into the electronic zone. Tatsuya Nakatani (March 10) has a gong orchestra, with instruments gently bowed more often than they’re struck. If there’s such a thing as an experimental harpist, it’s Mary Lattimore (March 25), whose ambient collaborations with Zeigler have her harp giving definition to his washes of sound.

Relatively traditional — at least on the surface — is Variant 6, a Philadelphia-based vocal sextet that ends the series on May 6, and typically sings a range from Monteverdi to newly written vocal works. Most likely, it will reprise last year’s collaboration with the percussion trio Square Peg Round Hole, heard on that group’s recent album Branches, in which voices blended with ambient textures.

Bowerbird artistic director Dustin Hurt is encouraging live performances — a particularly atmospheric possibility for Nakatani’s gongs, since the East Coast streaming time will be around dusk in the New Mexico desert where the artist lives. Some artists will be pre-recorded, though nocturnally, in the late-night slot that their streaming will occupy. Following a trend among U.S. presenters, performances will not be available on demand, partly to create a sense of occasion.

“Bowerbird is used to being a niche organization that had a small but dedicated audience in Philadelphia. Now, it’s competing on a world-wide stage,” said Hurt, who has previously produced major experimental music festivals of Feldman and John Cage. “We had to do something that feels different — and something that Bowerbird would do.”

“This idea has been around, inside my mind, for a long time,” said Hurt, who has enjoyed liminal states when listening to Feldman while lying on the floor (an option not available at most in-person concerts). “The music levitates very slowly, so that when you wake up, you wonder ‘Was I asleep for 10 minutes or an hour?’ "

Variant 6 member Elisa Sutherland said working remotely, and given the lag time that can come with conference technology, “there’s potential for a powerful, somewhat spooky experience.”

Liminal States concerts are pay-what-you-wish, with a suggested donation of $25. Information: