When is nothing something? When is empty full? Kannon, Sunn O)))'s first "solo" project since 2009's Monoliths & Dimensions, poses these questions sonically.

Stephen O'Malley and Greg Anderson enlisted old friends to assist: Co-producer Randall Dunn (who also plays synths), vocalist Attila Csihar, guitarist Oren Ambarchi, percussionist Brad Mowen, Rex Ritter on Moog, and a brass trio that includes Julian Priester, Stuart Dempster, and Tony Moore.

The album title is named for the feminine Buddhist deity of mercy, Kan'on (or Quan Yin), who "perceives all the sounds and cries of the world." (In the Tibetan male form, she is the bodhisattva Avalokiteśvara, who embodies the compassion of all Buddhas.) Kannon is structured as a three-part, numbered "triadic whole." Artist and theorist Aliza Shvarts, in her lengthy, soundly argued liner essay, describes them thusly: "Kannon 1": Invocation, "Kanon 2": Intonation, and "Kanon 3": Perpetuation.

She brilliantly argues the question: "What is metal about mercy?" and proceeds to critique the notion of metal's power as not merely penetrative but immersive -- this album is most certainly the latter.

"Kanon I" offers Anderson's earth quaking bass in full, dirty drone as O'Malley's guitar repeats an ascending and descending three-note pattern.

Csihar whispers, groans, and quietly growls poetic lyrics inspired directly by the Buddhist legend so elastically and deliberately, they are almost impossible to distinguish.

Emanating from a wall of white noise, they entwine their heaviness with layers of massive ambient sound from synths and low brass.

"Kannon 2" commences with squalling guitar feedback and raw, single guitar notes played in a pattern of four that repeat in reverse "choruses." The overblown bass drone enters at two-and-a-half minutes, and Csihar delivers his lyrics first in a Gregorian chant style that represents a "canonical" or traditional structure which, as Shvarts critiques, is itself a linguistic term that equates with Western male power structures.

But Csihar then shifts (effortlessly) to Eastern throat singing, a folk style shared by sheepherders and monks alike.

Sunn O))) turn the music's amplified power back on itself to allow his voices not only presence but fluidity.

That cooperative flow is broken by the sound of a violent explosion that gives way to a sarod-esque drone.

The effect is unsettling.

"Kannon 3" is a studio version of "Canon" from 2008's live album Dømkirke.

O'Malley's piercing two-note theme harmonically registers with the powerful synth and a rumbling bassline.

Along with waves of controlled noise, Csihar's guttural vocal builds with the music until he's shrieking apocalyptically.

The instrumental attack remains nearly glacial while its intensity increases exponentially.

Large swathes of formless noise flow through the crashing waves until a final swell of feedback consumes it all until it blacks out.

On Kannon, Sunn O))) illustrates through heavy sonic immersion that noise and silence are equals -- aspects of circular, self-perpetuating emptiness.

Like the persona of the deity, they generously receive and contain all the sounds of the world in all their dimensions of darkness and light.