Hempton stops at a creek just off the Palisades Lakes Trail, and explains how the highest sound frequencies are the first to fade, while the lower ones carry farther. Sure enough, the stream’s tone brightens as we approach, tinkling high sounds joining the initial baritone rumble. He points to rocks lodged in the water’s path, refers to them as notes, and explains how the stream will “tune” itself, or change pitch as rocks move. I nod, pretending to understand, but I’m lost somewhere between the real and the real esoteric. Clearly, I’m not the first to straddle this fine line. He reaches into his bag to fish out his equipment.
“I use these microphones to demonstrate what is possible to hear,” he says. “It’s a dichotomy of the modern world. We’re biologically prepared to listen, but we’re not hearing anything meaningful because there’s so much din in our lives.” I put on the headphones, and it’s like I’m hearing the woods for the first time. The forest swells with a symphony of subtleties like the flap and buzz of birds and insects.
My ears feel newly calibrated as we hike-listen-hike our way to Dicks Lake. We pause so often that it takes us four hours to cover the three miles to our basecamp, even though Hempton, 57, has the stamina and physique of someone half his age. He has backpacked much of his life, tackling long, challenging routes, but his discovery of sound changed all that.
“As soon as the microphone went on, I was like a five year old, ‘Why must we go so soon? Everything is so fascinating right here,’” he says.
After dinner beside the small tree-lined lake, I scurry to my tent, dodging raindrops. Lying in my sleeping bag, I recall one of Hempton’s favorite facts—that humans have eyelids, not ear lids. I listen intently to rain pattering on my tent fly—interrupted by Hempton’s snoring, the loudest sound he’s made all day.
A clear morning at dawn is typically when natural sounds travel best—the air is cool and less humid, and the world hasn’t woken up yet. This is when Hempton determines whether or not a place is quiet. How does he define it? Fifteen-minute periods without any intrusions of man-made noise. In 1984, Hempton identified 21 places in Washington with consistent noise-free intervals of 15 minutes or longer. By 2007, just three of those places were still quiet. Today, Hempton says, the average noise-free interval in wilderness areas and national parks has shriveled to less than five minutes during the daytime.
“We should ask ourselves not how much noise we’ll tolerate in our national parks, but does that noise have to be there at all? Does somebody flying from China to Los Angeles have to fly over Olympic National Park? No, they definitely do not,” says Hempton, who has calculated a detour that he claims would add less than one minute to the flight time and one dollar to the ticket price. “If you could go to Kayak.com and see that an airline is going to help keep our parks quiet, how could you not choose that airline?” he asks, as a mid-morning drizzle adds percussion to our soundtrack.