How Apple used ANC to build its best AirPods features
Once upon a time, noise-canceling headphones primarily existed for one purpose: air travel. Bose and Sennheiser were among the first on the scene commercially, blocking unwanted sounds for pilots long before wireless headphones were even a thing. Today, active noise cancellation (ANC) is not just commonplace, it's practically expected for any consumer headphone.
During the development of its four sets of AirPods with ANC, Apple has harnessed the power of its noise-blocking system to create a natural-sounding transparency mode, develop the automatic Adaptive Audio feature and create accessibility tools like Conversation Awareness. ANC is the basis for a litany of handy AirPods features, and with the AirPods Pro 3, Apple has honed this set of offerings even further.
As director of home and audio product marketing Eric Treski told Engadget. “With ANC, it was really about extending that capability to other use cases.”
The overall redesign of AirPods Pro 3
Before I get into the upgrades to the ANC system and the other tools that those unlock, I’d be remiss not to discuss how the overall redesign of the AirPods Pro 3 factors in. First, Apple adjusted the direction of the sound coming out of the earbuds so it’s going more directly into the ear canal. Next, the updates to the AirPods Pro 3’s fit — including the new foam-filled ear tips — create a better seal that helps make the ANC setup more efficient.
“The better fit allows us to diagnose what’s happening inside the ear canal,” Matthew Costello, vice president of audio and hardware engineering, explained. “We can actually make ANC more precise, compensate for leak and also better understand the geometry of the individual ear canals.”
Costello said that the product design team spent a lot of time on the new ear tips, arriving at a silicone-coated, foam-infused version for the AirPods Pro 3. He noted that these tips provide the best seal of any AirPods so far, which I can confirm, and that the passive noise isolation they provide is one aspect of the new-and-improved ANC performance.
A more precise ANC system
In order to improve the ANC tech, the engineers employed something called headroom control so that Apple could get more feedback from the microphones in the noise-cancelling system. Those internal mics monitor any unwanted noise that sneaks into the ear canal and prompts the ANC setup to make the necessary changes. The team was then able to optimize performance using a combination of software, geometry and acoustics.
An inherent trait of foam ear tips is that they’re better at blocking higher-frequency sounds, which Costello describes as "more challenging," so I asked how much of the improvement in overall ANC performance was simply due to this new component. Costello was quick to clarify it’s one part of a much wider system.
“It's a significant contributor, but it's part of the overall system performance,” he continued. “The understanding of what's actually happening in the ear canal helps us diagnose when you need more ANC, but the better seal makes the whole experience more reliable.”
The acoustics engineers, which include a dedicated ANC team, also redesigned and repositioned the noise floor microphones. These are the components that detect any unwanted sounds from either the earbuds themselves or your environment. Since there’s now a more direct path into the ear canal, there’s less room for interference or distortion. A new self-tuning algorithm then takes the data from those mics and identifies exactly what’s going on inside of the ear. Again, it’s all in the name of precision.
“It's essentially a cleaner signal that's more predictable,” Treski explained.
ANC’s role in other audio features
The evolving ANC setup became the foundation for many of Apple’s features on the AirPods and AirPods Pro. As the noise cancellation system improves, transparency mode does too. Now that the system can account for more frequencies, Costello said that this ambient sound tool is more customized to your hearing.
“We've actually been able to personalize transparency, because the pass-through information is much better,” he noted.
Because the AirPods Pro 3’s ANC can now cover a wider frequency range, Adaptive Audio is also more adept at picking up loud, high-pitched sounds. This increased the effectiveness of Apple’s hearing protection tools, which reduce your exposure to dangerously loud noises when, say, walking past a construction site, being bombarded by an ambulance’s siren or attending a concert. The re-tuned audio EQ profile helps the company better understand when you need more ANC in loud environments, and to better balance the mix of noise cancellation and transparency in those situations.
The same changes also support improvements in Apple’s hearing test. Thanks to these tweaks, you can now take the test in slightly louder environments than before without the feature asking you to move to a quieter spot. The hearing aid feature has been expanded as well, as Costello said the team added more gain so that the tool can correct higher levels of hearing loss.
“Because of the improvements to ANC, the [hearing aid] benefits actually extend deeper into mild and moderate hearing loss, to help even more people that have challenges with hearing,” Treski continued. All of the hearing health functionality on AirPods was developed in audio labs and in collaboration with audiologists. Apple tests the features with microphones in people’s ears, for both validation and safety, under the guidance of those clinical professionals. This confirmation lets the product development team know when these types of features may be ready for real-world use.
The most impressive part of Apple’s new Live Translation feature on the AirPods 4 with ANC, AirPods Pro 2 and AirPods Pro 3 isn’t the language conversion. For me, it’s the way active noise cancellation kicks in to ensure you can hear Siri speaking. When you begin a Live Translation session on a compatible set of AirPods, ANC lowers the volume of the person you’re speaking to and reduces environmental noise so that you don’t miss a word from Siri.
“We really wanted to ensure that you were able to hear Siri and have an understanding of the conversation in the best way possible,” Treski explained. “So, the idea is being able to really focus on that voice and not be distracted from other surrounding sounds.” Costello added that real-world testing, with careful attention to hide the unannounced products in public, is inherent to the development process.
“What started out as something that was really only used in an airplane is now doing things to help you translate language, preserve your [hearing] health if you’re at a concert, listen to lower levels of music or even take a hearing test,” Treski said.
Apple has taken the seemingly straightforward ability to block noise and applied it to so many of the features that have become synonymous with AirPods. The company probably still has more plans for its H2 chip, so there are likely even more ANC-powered features to come.This article originally appeared on Engadget at https://www.engadget.com/audio/headphones/how-apple-used-anc-to-build-its-best-airpods-features-130037859.html?src=rss
