+/-

Ryoji Ikeda’s turn-of-the-millennium work is like what would happen if an audiologist became a composer. +/- begins with a three-part suite, “Headphonics,” that as its title implies demands to be heard on headphones, because it sounds like one of those hearing tests where you’re supposed to raise your left or right hand when the high-pitched tone goes off. Its steadily pulsing rhythm is surrounded by a series of rising whines, nearly reaching the threshold of audibility but still somehow functioning as ultra-minimal music, not just sound. The “+/-” suite, in seven parts, focuses mostly on soft, very fast ticking sounds and tiny bursts of static; the rhythm shifts very, very subtly and gradually over the course of 10 or 11 minutes, until you’re not 100% sure you really heard anything change — you might have just hallucinated it. His control over frequency and the stereo field is absolute in its precision. This is an utterly fascinating sonic experience.