If anyone wonders why terms like “jazz” and “improvised music” don’t cut it, look no further than two musicians performing in town this weekend: Boston saxophonist David Gross and Denver trumpeter Ron Miles. Gross, who plays Sunday at Enemy, reduces free improvisation to its most elemental qualities. Although he has a jazz background, over the years he’s eliminated all traces of jazz harmony, melody, and rhythm from his playing. In fact, he’s one of those guys (like fellow Beantowners Greg Kelley and Bhob Rainey of nmperign) who’s managed to make his horn sound unrecognizable. For Gross, the saxophone is just a sound generator. On last year’s Things I Found to be True (Sedimental), he doesn’t merely employ extended technique–he eschews any sort of conventional approach to the instrument. Miniature scraping sounds, breathy columns of spilled air, tongue flutters, reed pops, vocal cries muffled by the tubing of his alto sax—those are just the things I feel relatively confident identifying. At other times it sounds like he’s drinking something with a contact mike attached to his throat while jiggling a crumpled piece of aluminum foil in the bell of his horn. Gross will surely test the limits of most listeners, but I really enjoy giving myself over to his alien sound world. He’ll be joined by Chicagoans Jerome Bryerton (drums) and Jason Roebke (bass); all three will do solo sets and then improvise together.

Ron Miles is best-known as a sometime-collaborator of guitarist Bill Frisell. His gorgeous tone and lyric style have been a good fit for Frisell’s delicate music, restrained without surrendering strength and suppleness. He’s made an equally good partner for Chicago guitarist Jason Steele—they’ve played together sporadically over the years (Steele’s from Colorado himself) and Miles is featured prominently on Some Wonderful Moment, the new album by Steele’s group. The tunes on Moment unfold slowly and patiently, with Steele’s warm chords going through loads of repetitive cycles, allowing the melodies to reach their full expositions. (There’s a definite rock influence, if the group’s take on the Elliott Smith tune “Alphabet Town” weren’t enough of a clue.) Unfortunately the structure and pacing becomes numbingly predictable by the album’s conclusion. Billowy, arpeggiated chords from Steele and pianist Keith Johnson form the foundation over and over, as the horn players—Miles, fellow trumpeter Thad Franklin, saxophonists Josh Sclar and Tim Sullivan—elaborate on the melodies with an almost tepid moderation. They kick up some dust on some of the longer pieces, like “Unexpected You” and “No Words,” raising the volume, tension, and density, but even that feels predictable by the second listen. The group has a good sound, and Steele’s composing has plenty of potential, but he needs to try cutting loose, putting more into the performances from the start rather than saving it for the climaxes.

The Jason Steele Ensemble plays Heaven on Saturday. The following night at the Hungry Brain , Miles and coronetist Josh Berman will join Steele and guitarist Bill MacKay as part of Remington 2+2, a free improv quartet that pairs Steele and MacKay with two “mystery guests” at each show.