Loading a music festival with experimental acts is itself a high-stakes experiment.

That was at least one lesson of Big Ears, a three-day event that debuted in Knoxville 18 months before Hopscotch arrived in Raleigh. For its first year, Big Ears appeared to have the most radical programming philosophy of any American “rock festival.” The exquisite Antony & the Johnsons shared the same room as Swans founder Michael Gira and minimalism master Philip Glass. Australian improvisational masters The Necks played the same art museum as the composer Pauline Oliveros.

But in 2010, Big Ears widened its focus and scale, incorporating more popular acts like Vampire Weekend and The xx alongside a more modest slate of esoteric performers. The transition suggested that perhaps a mid-size market in the Southeast wasn’t ready to support an entirely avant-garde event yet; when Big Ears disappeared for the next four years, it seemed that the festival even had to retool its hybrid model. During its last two successful runs, Big Ears has done just that.

Hopscotch has spent much of its half-decade tweaking a similar ratio of the strange and obscure to the accessible and immediate, trying to determine just how edgy the programming could be while trying at least to break even. The festival’s sixth lineup takes a bifurcated approach to the challenge, still digging into the experimental margins in ways that few other American festivals do while meting out the results more methodically.

On one hand, the tense, slow-motion Canadian collective Godspeed You! Black Emperor will become the densest and likely most divisive headliner in the festival’s history on Thursday night. Their sociopolitically animated instrumentals move between stretched drones and sustained crescendos, like an art-rock band working underwater. Their main-stage placement is a loud, public proclamation of how far outside the mainstream Hopscotch is willing to push, even in the space where it needs to sell the most tickets to survive.

In the clubs, though, Hopscotch has grown more judicious with its experimental acts, incorporating more bundles of hip-hop, electronic and even garage rock groups in the stead of straight noise or sound-art. And many of this year’s fringe acts favor the softer side of the spectrum. Two of the most interesting solo instrumentalists, Mary Lattimore and Zeena Parkins, are harpists. Two years ago, the Virginia string band Black Twig Pickers appeared as their aggressive acoustic drone iteration, Pelt; this year, they’ll play more tempered and traditional fare alongside the guitarist Steve Gunn.

And in the past, the festival has designated an official “improviser in residence,” intended to join various bands throughout the weekend. These have included busy free jazz drummer Chris Corsano, Japanese noise master Merzbow and former Sonic Youth guitar scorcher Thurston Moore. This year, it’s Owen Pallett, a violinist and vocalist known best for strange chamber pop under his own name and string work for the likes of The National, Arcade Fire and the Mountain Goats. Pallett is an intriguing choice, yes, just not one that promises the unhinged explorations of recent years.

This isn’t universally true. Even without this year’s excellent slate of metal acts, many of whom are also significant genre tinkerers, the bill still plunders extremes. Australia’s Lawrence English is one of the world’s best manipulators of long tones, which he builds into roaring compositions that seem somehow poised at the edge of density and delicacy. (With this year’s splendid A Year With 13 Moons, Jefre Cantu-Ledesma is joining the same league.)

The Norwegian songwriter Jenny Hval suggests a similar balance with her pieces, which counter magnetic melodies and compelling twists of phrase with sudden jolts of harsh noise and novel uses of samples. And though he sits at center stage with only a guitar, Tashi Dorji doesn’t meander through folk songs or fingerpicked beauties. Instead, his fingers ricochet across the strings, eliciting broken bits of phrases that chase one another in vivid six-string trips.

These are the riskiest highlights of Thursday and Friday, merely preambles for Saturday, one of the most experimental and provocative nights in Hopscotch’s history. Not long after Dwight Yoakam plays his first song in Raleigh City Plaza, Prurienta linchpin of the American underground for the last two decadeswill bring his intense mix of brutal noise and enormous beats to an opera hall. An hour later, the emergent producer Drippy Inputs will take a more efficient approach to a similar mix at Kings. And at The Hive, the ecstatic Baltimore free jazz trio Microkingdom sets the stage for a New York trio of kindred spirits, Zs.

When Zs played the fourth iteration of Big Ears back in March, their set perfectly paired the energy of open-ended improvisation with the magnetism of pre-written parts. By the show’s end, a series of hooks had emerged from the bedlam, offering moments of necessary clarity inside the whirlwind of a demanding music festival.

This article appeared in print with the headline “Rounded edges”