Turn Down the Noise: 3D Audio

Written BY

Emily Friedman

November 22, 2019

I was recently gifted a pair of Apple AirPods. I’ve had noise cancelling headphones before, but the AirPods Pro offer something new: Active noise cancelling and a transparency mode that uses built-in microphones to allow outside sounds in when I want them. I’m not an audiophile and this isn’t an Apple ad, but I am very sensitive to sound at work. I’m at my most productive with music in my ears, but as soon as a coworker answers a phone call, my concentration breaks. (Hell is other people, am I right?)

Source: Apple

The AirPods got me thinking about noise in the workplace and the role of sound in immersive experiences. As extended reality headsets improve and new tools make it easier to create 3D content, the absence of our other senses in XR is becoming more noticeable.

Big, bad noise

Most people today use headphones for attention management. According to Bitkom, nearly 50% of people wear headphones to mute their surroundings while 20% do so to focus on work. Millennials are especially concerned about rising decibels.

The government caps safe noise levels around 90 decibels, but Cornell University reports that office workers are most comfortable between 48 and 52 dB. To put that in perspective, casual chatting is around 60 decibels. Comfort aside, occupational hearing loss is one of the most common work-related illnesses, resulting in over $240 million in workers' compensation every year. Sound, it turns out, can significantly impact employee performance, health, and satisfaction.

The Sound of Work

As you can imagine, employees in many industries work in loud environments on a daily basis. OSHA set legal limits on noise exposure in the workplace in the early Eighties, but the government admits they're not low enough to protect workers from hearing loss. Each year, an estimated two million workers are exposed to hazardous levels of noise on the job. By industry, that’s 46% of manufacturing workers, 51% of construction workers, and 61% of mining, oil and gas workers. Although employers are required to protect workers' hearing by providing hearing protection and training, investing in low-noise equipment, and adjusting work shifts, some don’t and some employees simply refuse to wear protection.

The thing about hearing loss is that it's irreversible. Experts agree that regular exposure to anything over 75 decibels is enough to cause long-term hearing damage. For reference, most equipment operates above 100 dB (a bulldozer, crane, electric drill, and newspaper press are all over 75 dB). Noise has been linked to health conditions like heart disease, high blood pressure, and even adverse birth outcomes. Noise-induced hearing loss can reduce a person's ability to understand speech and hear high frequency sounds like alarms. Keep in mind, too, that a small increase in decibels represents a significant rise in noise and potential damage.

The truth is we don't fully understand the impact of noise on workers. Scientists are now realizing that sounds even lower than 75 dB over shorter periods of time can contribute to hidden hearing loss, a permanent reduction in neural response. I won't even go into the ecological devastation wreaked by human-generated noise.

The ear is where it’s at

If you’re wondering why a worker would neglect to wear hearing protection, current devices like foam and silicone earplugs leave a lot to be desired. Would you want to wear earmuffs if you had to remove them every time someone came over to talk to you? That’s where hearables and active noise cancelling come in.

Hearables are progressing rapidly thanks to the convergence of technologies such as low-power components, smaller AI processors, and advanced microphone arrays. Many newer hearables have integrated voice assistants and and can do real-time language translation. Sensear, for one, makes intrinsically safe, noise-cancelling earplugs and headsets for industrial users. The company's SENS technology isolates and enhances speech so the wearer remains aware of her surroundings while still protected from harmful background noise. Still, there is plenty of room for improvement.

Today's earbuds and earplugs are wanting for increased connectivity and additional capabilities like intelligent noise control and sensor tracking (location, movement, emotions, etc.). Imagine a hearable that cancels out sounds known to cause you stress or an in-ear device enabling you to interact with artificial colleagues like AGVs and collaborative robots. The hearable category has a lot of potential to both protect workers and enhance immersive experiences.

(Side note: The ear is actually a good spot for monitoring pulse and electrical brain activity.)

Audio AR

The last piece is audio. In addition to hearing protection, hearables might augment workers on the job, using sounds or auditory information to help users work faster, smarter, and safer. It could be as basic as a pre-recorded guide or step-by-step instructions in a person's ear, and it's already happening at companies like UPS. Audio can be modified in real time according to sensor and other data to deliver safety, machine, and other job-critical information right into the worker's ear. This is audio Augmented Reality, overlaying not visuals but sounds onto a user's environment.

3D Audio

Audio AR adds an extra layer of information, but what about sound in the virtual world? Immersive technologies are effective for training because they're experiential. Sound is a major part of the human experience, so in theory the addition of audio should make Virtual Reality training even better.

Sound helps us orient ourselves in space. It's called auditory spatial awareness. If VR is going to replace traditional training and design programs, it needs to get as close to the real thing as possible. For that, you need to be able to simulate sound localization. This is 3D audio.

(Side note: Occupational hearing loss negatively impacts spatial hearing, too.)

In case you’re wondering, surround sound is not the same as 3D audio. 3D audio is full-sphere surround sound. In a 3D soundscape, the user is able to understand where he is relative to the noises around him because sound is moving along with his movements in the physical environment. The complexity lies in the fact that your aural experience changes as you move through the world. Ambisonic mixing for virtual spaces requires sound to adjust according to where the user and sound sources are in the virtual world. The user's position relative to the sound sources is in motion, as are the sound sources themselves (objects). Today’s VR audio tech uses specialized recording systems and algorithms to mimic lifelike sound. There are also some ambisonic microphones on the market, custom rigs of omni- and bi-directional mics, and some encoding formats supporting 3D audio, but truly lifelike audio is not yet possible in VR.

Beyond Sound

We’ve been using audio wearables for decades: There was Panasonic’s AM radio designed to be worn as a bracelet in the early Seventies and the Sony Walkman, which turned 40 in July. We carry sound everywhere we go in the form of our phones, and yet sound has been an afterthought for AR/VR. From preventing occupational hearing loss to enabling a trainee to hear exactly how a healthy engine should sound, perfecting sound in extended reality will amplify the impact of XR in enterprise. Add touch and smell to the mix and we may be able to eliminate traditional job training altogether.

Main image source: Auditoryprotection.com

Further Reading