When an artist is as prolific as Will Long, one might assume there is little time for looking back and taking stock. Not only does the artist seem to produce a new ambient album every month, he also releases house tracks under his given name. Yet this tireless man not only makes tranquil, restful music, but pauses to reflect on fifteen years of this activity and where it has taken him. Memory Repetitions is a carefully curated piece of work, balancing one new composition against four remembered pieces. Together they form a five-disc masterclass in warm ambience, challenging and rewarding the unhurried listener.

The new piece, ‘Tetra’, is built around a sustained, fluctuating drone – the sound of a church organ half-heard. Rich, overlapping tones approach and recede like the tides. Whenever they draw close, they are accompanied by an analogue hiss like breaking surf. While many Celer albums concentrate on short tracks, Long is a master of larger, sustained pieces. Many of these use a similar to-and-fro swell that is aurally evocative and powerfully emotive, carrying the cadences of a searching nostalgia. On ‘Simultaneity’, the high water mark is more pronounced, threatening to break into something darker. In contrast, ‘Weak Ends’ has a tighter ebb and flow. Here, Long seems to capture a near-ecstatic sense of engagement that is deceptively difficult to marry with such a gradual aesthetic. This journey towards rapture is consummated by ‘Nichibotsu’ (Japanese for ‘sunset’, reminding us that Long is an American who lives in Tokyo) and ‘Caprice’, which each cast the hymnal and chorus shapes of devotional music.

This accomplished, self-assured piece of work is available in physical form from Smalltown Supersound, a Norwegian label home mostly to Scandinavian releases in various other genres. It should be noted that there is a mastering error on the fifth disc, which the label has promised to rectify. While the box set’s title points to its recycled content, the concept of memory works at a number of other levels in Long’s music. It is hard not to project a mournfulness into his backward glance, given the passing of Danielle Baquet-Long, who originally made Celer a duo. At a more practical level, one of Long’s key tools is the tape loop, which manipulates a form of physical memory to produce ethereal textures. Across each half-hour piece, repetition carves a mark in the memory, making the music seem familiar and recollected even as it unfolds.