Whispers and shouts of rock in Echo Park

Really, really loud or really, really soft.

Those appear to be the volume settings of choice in today’s rock underground, at least as that world was represented at last weekend’s ArthurBall, an ambitious two-day festival centered at two adjacent clubs in Echo Park.

That dynamic range was embodied by two acts that played at the same time Saturday. In the Echoplex, Pennsylvania band Pearls & Brass conjured the decibel-defying days of 1960s power trios such as Cream and the Jimi Hendrix Experience, while in the smaller Echo, the Bay Area collective Brightblack Morning Light emitted what must have been the softest sounds possible from amplified instruments.

Sometimes the extremes were found in one band. On Sunday, New York’s virtuosic Tarantula A.D. ranged from whisper-soft passages of cello and electronics to head-snapping explosions of prog-rock force.

One of the great services of an event such as ArthurBall, the creation of the Los Angeles monthly magazine Arthur, is the way it provides context for a sprawling, ever-shifting musical subculture.

That context might change soon -- these artists tend to resist neat descriptions and shrink from identifiable directions as soon as they appear -- but it was an often musically rewarding, always culturally instructive snapshot of today’s vital, non-mainstream music.

The lineup included cult experimentalists such as Chicago’s acoustic, exotic trance-spinning Town and Country and some names that even the general public might know. L.A. singer-guitarist Moris Tepper rocked joyously on Sunday with the help of his bassist Polly Jean Harvey, moonlighting from her illustrious solo career, and Queens of the Stone Age’s Josh Homme debuted the 5:15ers, a new teaming with longtime sidekick Chris Goss.

With more than 20 music acts in the clubs and additional attractions -- films, discussions, multimedia presentations, even a “full spectrum vibrational healing center” -- at outposts within a short walk along Sunset Boulevard, ArthurBall fulfilled its mission with dispatch.

Things ran reasonably close to schedule, it was an easy walk between the two clubs through an alley that also served as a setting for socializing and the rooms were comfortably packed without feeling overcrowded. And the artist-spectator wall was virtually nonexistent. Harvey stood in the crowd at the Echo applauding for Town and Country before her own set with Tepper, and out in the alley Homme happily posed for snapshots with fans.

“It’s really amazing,” said Arthur editor Jay Babcock, standing next to an ice cream truck in the alley Sunday evening following a set by prog-folk band Citay. “You saw Joanna Newsom last night? She did a whole hour of new music. How many times do you see that? An artist brave enough to do an hour’s worth of new music and an audience receptive enough to stay there and listen and applaud. That’s a special moment.”

Last summer, Babcock’s inaugural ArthurFest drew more than 2,000 people to Barnsdall Park on each of its two days with a combination of esoterica and star power (Sonic Youth, Yoko Ono). For this smaller-scale sister festival, in which attendance was about half that figure on Saturday, and down to about 500 on Sunday, Babcock had some different aims.

“We’re trying to get a diversity of genres, but I’m also trying to get lifers -- people who are in it for life. Like last night you could see it with the SST dudes. All those guys, they’re in it forever. And I think all the young bands we have, the ones in their 20s, they’re all in it for life. You can sense it about them. Those are the ones I’m interested in, those are the ones who have the most to give.”

The “SST dudes” were ex-Minutemen Mike Watt and George Hurley and Saccharine Trust’s Joe Baiza, whose roots go deep into Southern California rock -- back to the seminal punk label SST. On Saturday they presented the live debut of their band the Unknown Instructors, pairing their free-jazz-influenced improvisation with the beat-style poetry of Dan McGuire, with a brief drop-in from Baiza’s old bandmate Jack Brewer.

The other much-awaited debut, Homme and Goss’ 5:15ers, represented another of the region’s scenes, the “desert rock” associated with Homme’s pre-Queens band Kyuss.

The pair played blues and blues-based rock, sometimes with programmed rhythm tracks, sometimes with just their guitars or Goss’ keyboards. Economical and plaintive, it looks like another fertile direction for Homme.

The weekend’s musical diversity was striking, but trend-seekers might note the prominence of the 1960s influence in music and style. Brightblack Morning Light’s Nathan Shineywater and Rachel Hughes looked like the hippies in a pot-themed episode of “Dragnet,” while Winter Flowers and Lavender Diamond, groups based in the festival’s own neighborhood, evoked the Renaissance Faire aesthetic. Their slightly arty, completely non-ironic take on folk, as well as the more understated acoustic music of such players as the duo Mi and Lau, also were rooted in the ‘60s. Another band, Earthless, joined Pearls and Brass in the power-trio movement.

Does any of this have an effect on the music most people are likely to hear? Most of these artists would probably say that they don’t much care, and in some cases the prospects seem pretty remote. But pop music has always had a way of renewing itself by tapping into its subterranean veins, so you might want to dust off the headbands and brush up on your raga-rock.