How Apple developed the world’s first end-to-end hearing health experience

October 28, 2024

UPDATE

Inside the Audio Lab:
Discover how Apple created the world’s first comprehensive hearing health experience

Located in Cupertino, California, Apple’s advanced Audio Lab plays a crucial role in the innovative initiatives led by its acoustic engineers. The facility facilitates user studies through various listening environments and allows for rigorous testing of new features in anechoic chambers, which are designed to absorb sound reflections and block out external noise.

The Audio Lab is the central hub for the design, evaluation, tuning, and validation of all Apple devices that integrate speakers or microphones. It also serves as a focal point for a collaborative initiative spanning multiple years and teams that led to the development of pioneering hearing health features for AirPods Pro 2. Now available through a free software update,¹ this comprehensive experience actively reduces exposure to loud noises with Hearing Protection, offers at-home Hearing Tests, and assists individuals with perceived mild to moderate hearing loss by using AirPods Pro as a clinical-grade Hearing Aid.

As reported by the World Health Organization, around 1.5 billion people globally experience some form of hearing loss. “Hearing loss impacts people in every corner of the globe, often going unnoticed. It’s a fundamental aspect of communication and significantly affects health and well-being,” says Shelly Chadha, M.D., the WHO’s technical lead on hearing. “Technology can be a vital instrument for raising awareness and delivering interventions to those experiencing hearing loss.”

“Recognizing that every individual’s hearing is unique, we have developed a groundbreaking, end-to-end hearing health experience that is user-friendly and adaptable to a variety of needs. This is especially important as hearing loss affects people of all ages, regardless of their technological proficiency,” notes Sumbul Desai, M.D., Apple’s vice president of Health. “With the Hearing Aid feature, our goal was to create an intuitive experience that seamlessly extends your senses. We understood the profound impact this could have on people’s lives and its potential to enhance access to treatment for over a billion individuals.”

To facilitate these innovative features, engineers leveraged specialized spaces within the Audio Lab.

“From testing the faintest sounds for the Hearing Test to analyzing speech in noisy environments for the Hearing Aid, we can replicate real-world acoustics using calibrated soundscapes or conduct precise acoustic measurements at the touch of a button,” explains Kuba Mazur, Apple’s hearing health engineering lead.

The Longwave anechoic chamber is designed on a distinct foundation equipped with springs to isolate it from other areas, ensuring accurate sound measurements free from noise or vibrations. This chamber features a custom-built array of loudspeakers and microphones that assess how sound interacts with the human body, making it essential for the development of products like AirPods, iPhones, and HomePods.

“Your ears act as natural amplifiers, each uniquely shaped and often slightly uneven,” Mazur elaborates. “When sound reaches one ear before the other, it creates a time difference that influences our sound perception. Understanding this is crucial for us to develop experiences that faithfully reflect environmental sounds. We achieve this by having subjects rotate in a chair while wearing AirPods Pro to capture audio accurately.”

Elsewhere in the Audio Lab, the Fantasia Lab ensures that every audio product Apple produces meets the highest sound quality standards. It employs a spherical setup of 50 loudspeakers to simulate a diverse range of real-world sound environments — from shopping malls and busy streets to the sounds of airplane travel — within a controlled sound field.

To refine and validate the Hearing Aid feature, participants with various hearing levels underwent speech-in-noise testing in this controlled environment. This involved sitting in the middle of the lab while a complex sound scene, such as a bustling restaurant, played. Participants were then tasked with repeating words spoken by a single voice amidst the background noise.

“This lab is all about recreating real-life scenarios. Just as our users navigate through everyday environments, from shopping malls to dinners with family, we needed to ensure our features fulfilled their actual needs,” Mazur emphasizes, noting the importance of tuning and validating features like Hearing Aid, Conversation Boost, and Transparency mode for AirPods.

Additionally, the Audio Lab is permanently equipped with three clinical-grade audiometric booths similar to those typically found in medical settings for hearing assessments. For internal evaluations, the engineering team collaborated with audiologists in these booths to conduct thousands of clinical-grade audiometry and software hearing tests prior to advancing the new Hearing Test feature into validation studies.

Design also plays a pivotal role in the user experience, prominently featured in user testing for the new capabilities. One of the major focuses was simplifying the Hearing Test and Hearing Aid setup process, making it more accessible than traditional methods that often utilize unfamiliar numerical data encountered in a clinical environment.

“In developing our health features, we prioritize clarity and meeting users where they are in their journey,” mentions Heather Daniel, a producer in Apple’s Design Studio overseeing design aspects of health features. “For the Hearing Test, we realized that for many, this might be their first hearing assessment, so we aimed to make the process as seamless as possible.”

Achieving these streamlined experiences required collaborative efforts across Apple teams throughout the development process, ensuring the software adhered to clinical testing requirements while delivering an exceptional product.

“When considering the innovation, the technological sophistication embedded in AirPods, and the immense effort dedicated to crafting these advanced software features,” adds Mazur, “it’s clear that countless teams — from software and hardware engineering to design, health, accessibility, clinical operations, regulatory professionals, and human factors engineering — united to guarantee the highest quality and user experience.”

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How Apple developed the world’s first end-to-end hearing health experience