Apple's little secret: why the open AirPods 4 feature ANC
Despite their open design, Apple's AirPods 4 feature active noise cancellation. An interview shows how this was achieved.
The new AirPods 4 from Apple.
(Image: Apple)
With the ANC version of the AirPods 4, Apple has recently started offering its open in-ear headphones with active noise cancellation for the first time. Previously, this was only available in Apple's in-ears with the AirPods Pro, which seal the ear canal. In an interview, Apple representatives now provide an insight into the development process and how they managed to overcome the additional design-related hurdles.
Kate Bergeron, Apple's Vice President of Hardware Engineering, explains in an interview with Engadget that the recipe for this was intensive research for an optimal fit and the built-in H2 chip. The AirPods 4 are controlled by an algorithm that constantly adapts to the ear position of the headphones in real time, adjusts the noise cancelling and equalizer accordingly and thus ensures that the noise suppression continues to work.
Initially working with MRI scans
The investigations for an optimal fit have been underway for a very long time. The first EarPods, the wired version of the headphones, appeared together with the iPod. The headphones were included with the iPhone for many years from 2007. The first wireless AirPods then followed in 2016.
In the beginning, it was unclear how many different types of ears needed to be examined, Bergeron recalls. Apple collected the first data with MRI scans before later developing more efficient methods to make faster progress.
H2 chip plays an important role
Active noise cancellation with open-back headphones was once again a greater challenge than with the AirPods Max and AirPods Pro. The breakthrough was achieved in 2021, when the development team met for several days in one of Apple's acoustic labs. The technology demonstrated there was the basis for the AirPods 4, which have now been released.
One of the challenges of noise canceling with open in-ear headphones is the lack of acoustic insulation, such as that provided by the AirPods Pro with their silicone tips. Noise can therefore penetrate the ear canal more easily and it is more difficult for the software to decide which sounds should reach the ear. However, slipping in the ear also poses challenges for the technology. All of this is compensated for with more intensive calculations, but this in turn increases the battery consumption – the H2 chip gets to grips with this through higher energy efficiency.
Apple has also worked on the design and inner workings of the AirPods 4 compared to previous models. For example, the drivers have been set back slightly so that, among other things, the sound does not reflect back to the internal microphone.
(mki)