Bluetooth is a ubiquitous technology used throughout the industry. Apple relies on it for all kinds of products, including AirPods of course, but the pipe is too small: ” of course we would like more bandwidth “, Explains Gary Geaves, vice president” Acoustics “of Apple, at the site WhatHifi.
« We have to concentrate very hard to get the most out of Bluetooth technology, we have at our disposal a number of tips to maximize or bypass certain limitations of Bluetooth. “. The manager, who participated in the design of AirPods and in particular of AirPods 3, suggests between the lines that Apple is working on a way to expand or bypass the bottleneck of Bluetooth.
« Wireless technology is critical for delivering the content we are talking about “, He says of Bluetooth,” but this is also the case for the latency when you move your head (He alludes to spatial audio). Of course, Geaves refrains from saying more and maybe he said too much! A higher bit rate would allow, for example, to benefit from lossless audio with future headphones, files much heavier than standard AAC. And why not the planned 2nd generation AirPods Pro (more or less) for the next year ?
Everyone on the bridge
The interview conducted by WhatHifi is full of lessons and details on the design of AirPods 3, the latest headphones nice but nothing more launched by Apple. While Gary Geaves’ teams have developed this product based on a solid analytical foundation, this is not enough. ” Over the years, we have carried out a lot of measurements, and carried out extensive statistical research to obtain an acoustic analytical target. », Details the framework of Apple.
This information helps put the builder on the right track, but it’s only part of the way. ” We understood that listening to music is an emotional experience that people connect to in a very deep way. “. Apple then works with listening experts, ” people in the audio industry who try to refine the sound signature of each product, AirPods in this case, so that the sound reproduction is precise, but also exciting and moving ».
And it is far from over. For the AirPods 3, it was also necessary to manage the problem of spatial audio. No way to miss it here, which is why Apple is taking advantage of its privileged position in the world of music to further improve the audio quality of headphones. The teams in charge of Apple Music, but also GarageBand and Logic put their skills and their address books to contribution so that acoustic engineers and artists come to put their two cents.
And casually, it’s a hell of a job to come up with a satisfactory solution for the best listening in spatial audio, even more than in stereo. ” The shape of your ears, the width of your head, and to some extent the position of your facial features and even the shape of the head all make sure that everyone hears sound differently from others. », Specifies Geaves.
These differences can be calculated and put into categories, ” by what is called the transfer function relating to the head (HRTF) “. Apple has performed thousands of HRTF measurements, readings ” complex and difficult to do: we measure the sound, the response from your ear to a speaker in several different directions “. The goal was to come up with the best HRTF that works for everyone.
It is not a question of creating an average, but an HRTF measurement that is as close as possible to everyone’s perception. Gary Geaves specifies that while it is easy to develop a ” convincing demo », It is not so easy to develop a function which is suitable for the majority of people, on a majority of products and for multiple musical genres.
One last funny and meaningful piece of information about the work Apple has done for spatial audio: when watching a movie on Apple TV, the virtual speakers are positioned “further” from their position when listening from an iPhone. This is well thought out, because it would be a bit strange to have speakers placed very far from the small screen of the smartphone …