I wanted to know what it's like to nap inside a giant futuristic egg, so I went to a sleep clinic in downtown Manhattan to find out. There, I entered the MetroNaps EnergyPod — pods that look like very comfy chairs you'd expect to see on a spaceship. They're used by places like Google and NASA, and they're getting a sensory upgrade thanks to a new partnership with a company called Pzizz, which promises soundtracks that can put you to sleep.

Can music really make us fall asleep?

As I sat on the chair, I closed the visor and found myself in semi darkness. The chair lifted up so that I could lie down, and then the trip began. "Pzizz activated," a mechanical female voice said. "Enjoy your MetroNap."

The goal of the partnership between the two companies is to make the MetroNaps napping experience even better, by bringing in Pzizz’s "proven solution" to inducing sleep, says MetroNaps CEO Christopher Lindholst.

The "proven solution" is Pzizz’s use of psychoacoustics — a field of science that studies sound perception and how sound affects the brain. The psychoacoustic techniques Pzizz uses are supposed to induce sleep. And Pzizz CEO Rockwell Shah assures me that the company’s technology "intelligently combines music, voiceover, and sound effects in a way that will quickly quiet your mind, put you to sleep, keep you to sleep, and then wake you up feeling refreshed."

I am not a napper, and never have been. And as someone who sometimes lies awake in the middle of the night for no particular reason, I found the promise intriguing. Can music really make us fall asleep? Can sound frequencies tell my brain to just shut up and get to bed? The science says it’s not that easy. "Sleep is one of the most complicated neurological behaviors we have," says Seth Horowitz, a neuroscientist who’s done extensive research on human hearing and sleep.

The brain works in mysterious ways, and we don’t even know exactly why we sleep. We do know that if we don’t sleep, we die. And sleeping less than seven hours a night — like one in three Americans do — may be unhealthy, leading to an increased risk of obesity, diabetes, high blood pressure, heart disease, stroke, and frequent mental distress. But there are a lot of unknowns, and scientists are still debating whether napping is beneficial. Research has shown that napping can improve brain function, like memory and focus, but it’s also linked to higher mortality rates. "There’s a lot we don’t really understand about napping," says Yue Leng, a sleep researcher at the University of Cambridge, including how long a good nap should last.

In the meantime, psychoacoustic researchers are trying to crack the code of how to induce sleep. But finding the exact recipe for the perfect nap is hard. There’s research that shows that certain beats can trick the brain into matching the right frequency it needs to slow down and go to sleep. For example, beats that are around 2 or 3 Hertz — the same frequency of our sleeping brains — can induce the brain to snooze off. "That [frequency] is what entrains or kicks brain wave action into gear, and then the brain goes to that state," says Lee Bartel, associate director of the Music and Health Research Collaboratory at the University of Toronto. Bartel has studied how music affects the brain for 20 years.

Certain beats can trick the brain into falling asleep

Another psychoacoustic technique is the use of low-frequency vibrations that have little momentary glitches, also called pseudo-random low-frequency vibrations. Those sounds, which affect the inner ear, are meant to make you drowsy by simulating the same sleepiness associated with prolonged motion — a condition called Sopite Syndrome. It resembles the way you nod off in a moving car, or how a baby falls asleep while being rocked. "That slow, not-quite-perfect rock back and forth motion is very good for inducing sleep, and has been the basis of lullabies and trying to put kids to sleep for thousands of years," says Horowitz.

The Sopite Syndrome technique is one of the psychoacoustic techniques that Pzizz uses. The soundtracks included in the MetroNaps EnergyPods vary based on how long you decide to nap — anywhere between 3 and 90 minutes. I chose a 20-minute nap with a voice that guided me through relaxation. "For a few minutes, I’ll guide you as you prepare to relax," the pod said, this time in a deep, low, and soft male voice that reminded me of Morgan Freeman.

The man told me to close my eyes, set aside any concerns and considerations, stretch my muscles from head to toe, and breathe more and more easily. At a certain point, the voice started reciting a Celtic saying about the deep peace of the running waves and the smiling stars, which kind of made me roll my eyes. The sound in the background was soothing and pleasant; it reminded me of the music you’d hear in a church or the whale section of an aquarium. There were harps, and it was like being underwater.

The guided relaxation is meant to shift the focus of your mind from your daily problems to your body, so that your tight muscles can relax, says Bartel. "That’s the crucial thing," he says. "You need to change your focus." But having a voice talk you to sleep doesn’t work for everyone. Just like binaural beats, low-frequency vibrations, and other psychoacoustic techniques can’t put everyone to sleep. And what works for someone might not work for someone else. One person may like to sleep with a white noise machine, while another prefers classical music. My mom falls asleep listening to the radio, but I need silence. "You can resist the entrainment," says Bartel. "The entrainment is not the inevitable. Just because you get a boost in delta brainwave activity doesn’t mean that you will be asleep."

"This is 2016, and by God we’re gonna have state of the art sleep."

A lot of it has to do with placebo, Bartel says. Products that promise you the best sleep you’ve ever had because they’re backed by science can convince lots of people that they’ll work — just because they sound legit. "We can get a lot of satisfied customers by just making them believe that this is going to be really powerful exotic and it’s going to be powerful because it’s exotic," Bartel says. That’s some of the appeal that the MetroNaps EnergyPods, and other napping pods, have. A very comfy, zero-gravity chair and a pair of headphones with relaxing music would be probably as effective, Bartel says. "It has to do, I suppose, with the technological novelty of it," he says. "We are in the 21st century, this is 2016, and by God we’re gonna have state of the art sleep. So it’d better cost $12,000 and look like a space module."

But I’m an inherently skeptical human being and I’m not sure I buy faith in the "exotic." Just before my 20 minutes of napping were up, a pink light turned on in the EnergyPod and the voice gently told me to wake up. As I expected, I hadn’t fallen asleep for one second.