Tech

What is Subsound®? The ‘sound’ part.

Cocoon Labs

Cocoon’s secret sauce is Subsound®. It’s the technology making our home security incredibly simple and powerful. Because of our unique Subsound® technology, protecting your home has never been easier. With Cocoon you can feel safe knowing it will alert you when it matters.

Subsound® technology works by using three things:

  1. Sound
  2. A smartphone
  3. Machine Learning

Here we’ll explain how Subsound® uses sound to sense movement, and how that gives you multi-room protection from one Cocoon. Part 2 and 3 (coming soon) will explain how it uses your smartphone and machine learning.

How can you detect movement through sound

Cocoon’s Subsound® technology uses sound to detect movement around your home, not just in the room it sits in. This is possible because sound travels through your home, causing the air and walls and floors to vibrate, essentially turning your house into an amplifier!

Have you ever felt vibrations from music with a heavy bass line? How, even if you can’t hear the notes of the music, you can feel them? They travel through the air, the floor, the walls. You sometimes even feel them vibrate in your chest. That’s because those notes, and all sounds we hear, are actually vibrations moving the air that our ears can detect.

Moving through a space makes the air you’re pushing through vibrate. Walking across a room sends vibrations through the floorboards you’re stepping on. Singing the right note, loudly enough, can make a glass vibrate so violently that it cracks.

Humans can only hear within a narrow band of sound. Within that range of 20 to 20,000 Hz we hear birdsong, dogs barking, children giggling and engines roaring. But go much lower than this and we don’t hear it at all. (Although we may well feel it!) The sound that is caused by movement is too low for us humans to hear, but not Cocoon! Cocoon hears what we can’t.

Put simply, Cocoon hears the sound of movement.

How can Subsound® give multi-room protection?

All sound travels at the same speed in air, but high pitched sounds travel as lots of short waves while lower sounds are longer waves. The shorter waves are more easily absorbed by objects they hit because they’re too short to wiggle around them. Picture how hard a toddler would find it to climb over their toys – while an adult simply steps over them. The toddler is the high note, it can’t travel far because there are too many obstacles it can’t climb over. The adults are the low notes, they can easily travel around your home because, what may be a tough barrier for a toddler, is only a small step for them.

Cocoon doesn’t listen for the high pitched sounds, but instead, for those deep sounds that we can’t hear, known as infrasound. The adult, not the toddler. You may have experienced the movement of sound as the walls of a nightclub shake with the music, or as your body moves with the drumbeat when you’re dancing near a speaker. You are feeling the vibrations of sound. Just think, as the bassline hits your ears the sound waves are travelling through you. You really are part of the music.

Low frequencies resonate through your home more easily than high frequencies. As movement creates very low frequencies, the sound of movement travels through the rooms and floors of your home. Tuned to sense these low frequencies, Cocoon has the power to give you multi-room protection from just one device.

How does Cocoon use the sounds we can’t hear?

In the same way that you feel the bass hitting you, Cocoon has a clever microphone inside it that acts as a motion detector. It listens for subtle vibrations in the air caused by movement, building up a picture of those sounds. Like a fingerprint, this is unique for every home. If you’re away from home and it senses movement that isn’t normal, Cocoon sends an alert to your phone. (More on this, coming soon, in What is Subsound®? Part 3: Machine Learning)

This means Cocoon can detect movement before something crosses in front of its camera lens. Unlike traditional motion detectors that are so easily set off by spiders and moths, or modern smart home security cameras that rely on something passing in front of them, Cocoon senses motion through walls and floors. It is unique in offering multi-room protection from one device, and this is possible because sound travels through the air of your home.

Cocoon is not listening to your conversations

Because Cocoon is tuned to listen for low level vibrations caused by movement – called infrasound, it does not listen to your voice in the way that Amazon Alexa does! If you’re away from home and Cocoon senses something suspicious moving through the air you get an alert. That alert will not be triggered by someone chatting loudly outside your house, unless their voice is so deep that it falls into the infrasound range, so other humans can’t hear them! This is because the vibrations caused by the sound of human voices are not like those of an intruder in your home. And Cocoon is smart enough to know the difference.

Subsound® never listens to audible sounds, like voices and music and Cocoon only does so when it’s recording video. This happens when you “Watch Live” or when there’s an alert sent to your phone. This is great for having a smart home security system that respects your privacy.

The power of sound for better home security

The power of sound means you can have multi-room home security, from one Cocoon. It’s complete security without installing sensors on windows and doors, or intrusive cameras throughout your home. Cocoon set out to make home security without the hassle, that’s simple but also incredibly powerful. And to package that all into one beautiful gadget. The way we did that? Our unique Subsound® technology.