Phillip Sollmann (Efdemin) and Konrad Sprenger here tackle some of the most controversial and interesting aspects of the organ - an instrument that since ancient Greek and Roman times was devised to allow a single performer to produce a larger ensemble sound. ‘Modular Organ System’ started life in 2017 as an installation piece devised by the duo as a new model for a modular system that could be used for composition, performance and tool development in acoustic space. This album is the first proper documentation of that work, offering two long-form drone compositions that consider space, tonality and acoustics. Sprenger built his first organ as far back as 2002, but for this iteration the duo built the system out of tubes, air pumps and vibrating reeds, which they could place around a space as if the instrument were a sculpture. Visitors were encouraged to wander around the installation and wonder as the sound shifted; sometimes hearing just electrical buzzing from its motors, and sometimes just its engrossing low end frequencies. “The visitor has the impression of being inside an organ itself," composer Arnold Dreyblatt writes in the liner notes, "rather than listening to it externally."

On 'Modular Organ System', we don't have the benefit of being able to physically move around the space, but we do get to interface with the root of Sollmann and Sprenger's process: its peculiar tonality, commanding sound, and hypnotic interplay of airy, ancient drone. They use pure power to lull us into the opening side, with non-tempered harmonics that boom from the speakers. Even without seeing the instrument itself, it's easy to hear its unusual properties - at times sounding like archaic, phased woodwind playing alongside a church organ, or atonal bagpipes in the distance, over a hill or a mountain. The slow-moving wails connect us wholly to history, but the recording and texture feel decidedly modern.

On the dense, overpowering second side, the duo layer their drones into a wall of humming vibrations. These elements crack and distort naturally, sounding as powerful as Tim Hecker's signature granulations but blessed with spiritual magic. Midway into the piece, the drones descend into near silence before building again into a slowly chugging rhythm that seems to directly reference Sollmann and Sprenger’s motorik collaborations with Oren Ambarchi, and which leave us re-evaluating the instrument’s technological and historical boundaries. It makes for a stunningly meditative, disorienting listen.