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The boom of a calving glacier. The crackling rumble of a wildfire. The roar of a surging storm front. They\u2019re the noises of the living Earth, music of this one particular sphere and clues to the true nature of these dramatic events. But as loud as all these things are, they emit even more acoustic energy below the threshold of human hearing, at frequencies of 20 hertz or lower. These \u201cinfrasounds\u201d have such long wavelengths that they can travel around the globe as churning emanations of distant events. But humans have never been able to hear them.<\/p>\n
Until now, that is. Everyday Infrasound in an Uncertain World<\/em>, a new album by the musician and artist Brian House, condenses 24 hours of these rumbles into 24 minutes of the most basic of bass lines, putting a new spin on the idea of ambient music. Sound, even infrasound, is really just variations in air pressure. So House built a set of three \u201cmacrophones,\u201d tubes that funnel air into a barometer capable of taking readings 100 times a second. From the quiet woods of western Massachusetts, House can pick up what the planet is laying down. Then he speeds the recording up by a factor of 60 so that it\u2019s audible to the wee ears of humans. \u201cI am really interested in the layers of perception that we can\u2019t access,\u201d he says. \u201cIt\u2019s not only low sound, but it\u2019s also distant sound. That kind of blew my mind.\u201d<\/p>\n House\u2019s album is art, but scientists made it possible. Barometers picked up the 1883 eruption of the South Pacific volcano Krakatoa as far away as London. And today, a global network of infrasound sensors helps enforce the nuclear test ban treaty. A few infrasound experts\u2014like Leif Karlstrom, a volcanologist at the University of Oregon who uses infrasound to study Mount Kilauea in Hawaii\u2014helped House set up his music-gathering array and better understand what he was hearing. \u201cHe\u2019s highlighting interesting phenomena,\u201d Karlstrom says, even though it\u2019s impossible to tell exactly what<\/em> is making each specific sound. <\/p>\n