Last year, engineers added new sidewalk railing slats on the Golden Gate Bridge in San Francisco. They replaced 12,000 wide slats with narrower ones to give the bridge a slimmer profile and made it safer during high winds.
But the retrofit had an unexpected effect: because the engineers didn’t do acoustic testing of the new slats, they inadvertently turned the bridge into the world’s largest wind instrument. On particularly windy days, the bridge “sings” with a loud - and some say ghostly - hum.
While the engineers tried to figure out the proper way to reduce the Golden Gate’s new and notorious hum, musician Nate Mercereau took this as an opportunity to play a duet with the bridge.
“... the note the bridge makes seems to fluctuate depending on where you are standing,” Mercereau said to San Francisco Chronicle. “It plays four notes pretty solidly. There’s an A, B, and a G that warble together and create the ominous part of the sound, and then there’s a high C that holds it all together.”
This inspired Mercereau’s latest project, titled “Duets / Golden Gate Bridge,” where he performed alongside the humming bridge.
“It was an amazing project, but definitely had some unique challenges,” [sound engineer Zach Parkes] said. “A normal-size piano is difficult enough to record evenly and clearly, especially when it’s outside. How do you mike a 9,000-foot-long harp that requires 20 to 25 knots (of wind) to play?”
Hear the amazing duet in Mercereau’s YouTube clip below: