A couple Fridays ago, Dutch cellist Ernst Reijseger came to Cambridge’s Zeitgeist Gallery, which is one of several artist-run alternative-music venues that have been making the Boston area a stronghold for jazz and new improvised music. His solo show was part concert, part performance art. The opening number moved from long, still tones through faster, ever-widening jazzy intervals into abstract sound and back, illustrating his ability to appropriate techniques and ideas from unrelated sources and make them work together. Reijseger also played the part of the straight-faced musical comedian, and his irreverent humor emerged on the second number, a stately Baroque dance theme performed with all due dignity until it suddenly stumbled and got embroiled in a pie-throwing fight of squeaks and squeals.

Some of Reijseger’s musical juxtapositions were as affecting as they were thought-provoking. He began a lovely Abdullah Ibrahim tune by imitating on the cello a scrap of conversation overheard from the street outside the crowded gallery. Singing along amateurishly as he played the melody, he created a sonic contrast that heightened the tune’s poignancy. After the abrasive intro, I couldn’t help wonder how something so pretty started out from something so harsh.

At the beginning of the evening’s second set, Reijseger inserted clips into his cello strings à la John Cage and wandered like a griot through the audience, playing kora-like pizzicato patterns — a provocative juxtaposition of ancient and modern. Then he sat down and transformed himself into a parody of a folksinger, holding the cello in his lap like a guitar and singing with irritating sincerity an awkward ditty with only one lyric — “Hi there.” He followed that up by launching into an excruciating series of blues clichés played badly. He pulled a similar stunt for the encore, playing a fake classical sonata with the wrong side of his bow. Something like listening to Beethoven through radio static, it was funny, but Reijseger was also making a serious point by dismantling empty gestures and reconstructing them into something meaningful and new.

The following Wednesday, Chicago-based reed player Ken Vandermark appeared at the Tremont Theatre, which, like the Zeitgeist, has been providing a valuable forum for the local avant-jazz scene. Vandermark has roots in New England and often revisits Boston to work with area musicians. This time he performed as part of two quite different Boston trios — Triple Play, with bassist Nate McBride and drummer Curt Newton, and a group with McBride and pianist Pandelis Karayorgis.

Triple Play have the same instrumentation as the better-known DKV trio that Vandermark works with in Chicago, but here each member has his own identity. Less concerned with flat-out blowing than the DKV juggernaut, Triple Play flex their muscles, but they also play with greater delicacy and space and more concern for composition and contrast. This was the final concert of a five-day tour, so the members were well attuned to one another. The trio broke up into duos and solo passages on the opening number, keeping the textures and the density of the music varied. An untitled McBride tune boasted a powerful, multi-layered arco bass solo and a nicely orchestrated drum solo in which Newton paired different parts of his kit, like toms and hi-hat or snare and ride cymbal, in successive passages. Vandermark worked up his biggest head of steam on the final tune, stringing short, blunt phrases together in rapid-fire lines of ever-increasing tension.

The drummerless trio who followed played tunes from their first album, No Such Thing, on the Vermont-based free-jazz indie Boxholder. The music was rhythmic and powerful in a quiet sort of way — chamber jazz with an attitude. The trio’s subdued dynamics and oblique interactions were reminiscent of the great Jimmy Giuffre trio with Paul Bley and Steve Swallow of 40 years ago.

Karayorgis, who co-led a Lennie Tristano tribute quartet several years ago, excels at personalizing historical references. On “Summer” and “Let Me Know,” he used many of the same devices that Bley did — predominantly soloing with just one hand, leaving sudden silences in his lines, interjecting chords at unexpected moments. What distinguished him was his feel for time, his dark harmonies, and his heavier touch. McBride was often the axis around which the other two revolved, especially on “Skid into the Turn” and “Disambiguation.” Vandermark stuck mainly to his dry, expressive clarinets (another nod to Giuffre), and his plaintive, vibratoless tone blended beautifully with the other two instruments, especially on the concluding “Pending.”