The Science of Sound and Sleep
Why New ‘sleepbuds’ Might Be the Secret to Helping You Sleep.
Have you ever woken up to the sound of a snoring partner, roommate or family member? Perhaps the noise isn’t even that loud; just a rasping nasal breathing noise. It shouldn’t be that disruptive, but somehow it is. You’re there, in the dark, unable to hear anything else. Falling back to sleep feels near-impossible.
Poor sleep is a legitimate problem, and unwanted noise that wakes us up or keeps us lying awake — like traffic noise or a snoring roommate — are all major contributors. “Chronic sleep disruption has been linked, for examples, to cardiovascular disease, mental health problems and diabetes,” says Jeffrey Ellenbogen, a Bose consultant, sleep-medicine physician and the director of the Sound Sleep Project, which is focused on solving sleep issues. “And reduced sleep can impair daytime function, leading to reduced function at work, and more importantly, impaired attention that can cause things like car crashes.” These are all bad things!
Our vision may take in more complex information about the world around us than our ears do, but our hearing ties more deeply into our limbic system, the primal portion of our brain responsible for emotions and survival instincts. This is because humans evolved to detect threats from any direction, at a distance and even when we’re asleep, triggering us to react and protect ourselves. And, like all of our senses, what our hearing is attuned to detect is change. We adapt to steady sounds like the murmur of a flowing stream or the sound of crickets; we alert to the unexpected or unpredictable — the crack of a twig break that might mean something dangerous approaches, the sudden muted laugh from a party in a neighboring apartment or the not quite predictable next drip of a faucet or snore of a partner. And, when we alert, the same parts of our brain that are involved in our fight-or-flight response get stimulated. And we…can’t…get…to sleep.
At this point you might be thinking, “sure that makes sense. But what can I do about it?”
Enter ‘sleepbuds’
Bose’s engineers have come up with a solution in their new sleepbuds™, a set of extremely low-profile earbuds that don’t stream music but are instead loaded with carefully designed sounds. The earbuds themselves function as passive sound-blockers, capping the end of the ear canal and dampening outside noises. The sounds they play are designed to mask those unpredictable and changing sounds that can wake you up or keep you tossing and turning. You may be familiar with masking from those “white noise machines”. Masking involves playing a consistent, steady sound just loud enough to hide sounds that grab your attention. But Bose’s sleepbuds are much better than putting a noise machine in the corner of your room or turning a fan on the high setting. The sounds in sleepbuds are engineered to work with the sound-blocking of the earbuds so that the masking can be quieter. That helps make masking better — pleasant, unobtrusive and easily ignored. And last but not least, the sleepbuds, happily, have a silent alarm feature to help ensure you wake you up even while they’re inserted.
White noise: explained
People often call any steady noise made up of a broad mix of frequencies “white noise”. To engineers that term has a more specific meaning: white noise has the same energy at all frequencies, just like white light is an even mix of light of all colors. True white noise can be used for masking, but you wouldn’t want to; it’s not very pleasant. It’s like the sound of steam escaping from a boiler, kind of sharp. Engineers use other colors to describe other mixes of frequencies: pink, gray, red and brown for example. Bose’s sleepbuds include one such colored noise, which they’ve named “warm static.” It’s very good for masking. It’s completely steady, very ignorable and just the right mix of frequencies to work with the earbud’s sound blocking to mask common sounds — low frequency to cover up a guttural snore as well as some mid and high frequencies to deal with quiet voices out on the sidewalk or that rattle in the hotel room air conditioner. (And actually, it’s a common misconception that snoring only occupies lower frequencies — it often occupies higher frequencies as well).
But this is just one sound Bose provides. They’ve also designed other sounds for masking: one that evokes a babbling brook and another wind rustling through leaves. There’s one that sounds a bit like a metallic box fan and another that’s like the ebb and flow of the surf. There are ten in all, with more sounds on the way. Each person should pick a sound that works best for them. What does that mean? Most of all, it should easily fade from your attention; ideally it should have pleasant associations for you. If you grew up in a city, maybe the rush of traffic (sans sirens) would be soothing, but a campsite accompanied by crickets would be jarring. If you have fond memories of scouting, campfire and crickets might be perfect. Grow up near water? The sound of the surf or waterfall might be the best choice.
Regardless of the content, there are rules for what kind of noise works here. The Bose sleepbuds don’t allow you to play music, because even the most droning tunes still have too much variation to work in this scenario. And it isn’t noise cancelling; noise cancellation is a technology that actively senses sound and then supplies a digitally-constructed opposite sound to counter it. If you remember high school physics, sound is expressed in a wave; sound cancellation creates the same wave structure as the sound outside, except with valleys where the peaks are and peaks where the valleys are.
The solution: fighting noise with…more noise.
The problem with noise cancellation for sleep interruption prevention is that it can’t completely eliminate the noise. In fact, no technology to reduce noise — passively, actively or in combination — entering your ear canal can create complete silence. Some sound reaches your inner ear through other paths: your nose, an open mouth, even your skull. The only way to make an unwanted noise at typical levels completely inaudible (for someone with normal hearing) is to mask it. Besides that, noise cancellation requires more electronics in the earbud and a bigger battery, which make the earbud bigger and would make it uncomfortable, at least for those of us who like to sleep with an ear burrowed into a pillow. Hence sleepbud’s combination of passive noise blocking and noise masking. This constant stream of engineered noise is specifically designed to help combat bursts of sound.
It might seem odd to fight noise with … more noise. When you think about it though, people are already doing this, and many of them do it every night! They use noise machines, TVs, headphones — all to create a pleasant sonic backdrop to help them fall asleep or stay asleep. What’s new with Bose’s sleepbuds is a way to have the right sound to set the stage for sleep and mask those things that would otherwise disturb us — like that snoring partner right next to you — combined with sound-blocking to allow that masking sound to be quieter, more pleasant and more easily ignored. And, all of this in a tiny earbud that nestles comfortably into your ear. It might be just what every oft-interrupted sleeper needs.
Sponsored by Bose, The Sound of Innovation explores the ways in which sound shapes our experience of the surrounding world.
