A little over three years have passed since Keith Fullerton Whitman first diverged from his break-powered Hrvatski moniker to introduce the world to his groundbreaking “Playthroughs” system via his Kranky debut of the same name. A sprawling exploration of processed acoustic and electric guitar via carefully chained effects, the pieces earned critical (and even popular) acclaim, and formed a continuously evolving backbone of Whitman’s live performances. Since then, endless fine-tuning, reworking, and expanding of the live formula, as well as experience gained in producing subsequent recorded work, has allowed Whitman to display endless new iterations to his audiences. And now, two of the latest, captured as a single 40-minute work live in Lisbon, Portugal last October, are to be offered as a document.

Without getting too technical, it is worth taking a moment to describe the deceptively simple “Playthroughs” setup. Whitman typically plays single guitar notes, feeding them into his laptop to be paired automatically with identical synthetic tones. These smooth electronic notes, which match the slightly unpredictable pitches of the source guitar, are the primary sonic ingredient of a “Playthroughs” piece. Next they are fed into a tape delay unit, with four slightly different delay intervals, allowing a single note to be drawn out and broken up, gradually moving in and out of phase with itself in a dynamic, unpredictable murmur. By carefully overlaying multiple guitar notes in this way, Whitman creates slow-building waves of guitar. Finally, that sound can be run through a variety of other processors to continually reshape the results, allowing it to ebb and flow, splinter and reform. In essence, “Playthroughs” is the science of creating live ambient washes from various non-electronic sources.

It is in this manner, simply building up layer upon glistening layer of notes, that Lisbon opens. It’s a gradual process, and a familiar part of Whitman’s arsenal, but effective nonetheless. By the seventh minute, the mood has begun to shift as deeper, more dissonant sounds creep in and the primary harmonic sheen begins to break up into splinters of noise. Soon a consistent bass rumble is in place, eventually to submerge the entire track before the whole builds, still at glacial pace, into a buzzing wall of feedback. Whitman claims to be, at last, embracing “traditional ‘loud guitar’ concepts”, a statement that seems most substantiated by this stretch of feedback, and by the faster electric guitar segment that immediately follows to close the first of the two pieces. Thankfully, even at its noisiest, the sounds never seem to lose the complexity and resolution that characterizes this work. On the second, much less typical piece, Whitman brings together a variety of processed and unprocessed field records, sounding for a while as if he is simply banging around on stage with his equipment. These component clatters and bangs gradually coalesce into pools of noise and emergent guitar tones, building into a glorious crescendo once again.

Lisbon’s single two-part track is in many ways an impressive musical statement, and an interesting one to any who have been following Whitman’s developing technique. The sounds are dense but clear, and reveal exciting new facets of the “Playthroughs” system’s potential. Even so, such a gradual, unbroken 40-minute piece is an imposing listening experience for most, and where such a composition can be highly compelling live, when it is still unpredictable, the subtlety of the variations here allows them to fade into the background on subsequent listens once the larger shifts are no longer surprising. In this way, the shorter, more focused pieces in past “Playthroughs” work may be preferable for casual listening. Even so, Lisbon is exactly what it claims to be: a pristinely captured live snapshot of one step in an ever-shifting progression. And as such, should be of interest to anyone seeking more insight Keith Fullerton Whitman’s ongoing experiments.