A solitary brand of ambient Muzak has become big business for wellness companies selling increased productivity through sonic curation. This idle music is designed to recalibrate the brain—to help the listener focus better, sleep better, live better. These aims guide the electronic singer-songwriter James Blake’s new album of soundscapes, created in collaboration with the A.I.-powered app Endel, as part of its selection of real-time, personalized sonic environments. “Wind Down” is music for decompression, designed to ready the listener for bed. Composed entirely of chiming keys, airy synths, and disembodied vocals, the record is soothing, winding, and trippy, like navigating the gorgeous, uncanny architecture of the smartphone game Monument Valley. As an aural relaxant, it is nearly hypnotic, a balm that imitates the ocean and the sky; as an album, it can feel like the soul has been separated from the machine and is drifting off on its own.