Drone has always been a vital part of Thomas Meluch's music, whether working with Rafael Anton Irisarri as Orcas or on his own as Benoît Pioulard. The earliest Pioulard albums punctuated lovely folktronic pop songs with ambient interludes, which gained equal footing on later works like Hymnal. With Sonnet, Meluch goes even deeper into Benoît Pioulard's atmospheric side: While he was making the album, he removed the vocals from several tracks, letting their murky, tape-damaged acoustic guitars and electronics, which recall early Bibio and Boards of Canada as well as Orcas, speak for themselves. Meluch's voice doesn't surface until halfway through the album, where "A Shade of Celadon" -- one of the moments closest to his earliest work -- sounds like he's singing into the wind. As much as his singing is missed, this restraint celebrates the architecture of his music. Throughout Sonnet, Meluch plays with notions of structure and freedom in subtly fascinating ways that reflect a great amount of care without feeling labored. Even the song titles combine into a modern take on the time-tested sonnet, forming a poem that comments on the power art has to create stylized perspectives and haunting beauty. This flow between parts and whole extends to the music: Sonnet incorporates details like the almost tactile-sounding thumb piano on "Whose Palms Create" into tracks that flow into each other seamlessly, taking understated but intriguing journeys along the way. Pulsing textures and a tenacious melody emerge from the drones that begin the standout "Upon the Break Arch," while "The Very Edge of Its Flame" expands and extends those drones into a scintillating peak that feels like it could go on forever. But where Hymnal's similarly massive tracks sometimes felt imposing, Sonnet's atmospheres always retain some intimacy. This is the first Pioulard album to feature entirely analog effects, and they warm up Meluch's music while giving it the immediacy of a grainy snapshot; "So Etched in Memory" could be saturated in pure, welling emotion. As with the best music of this kind, Sonnet rewards paying rapt attention to its minute changes as well as its wider sweep. Either way of listening reveals it as a beautiful, affecting exploration of form and freedom.