The Custom W1 Chip Inside Apple's AirPods Is More Than Just a Bluetooth Controller

While the new iPhone 7 siblings and Apple Watch models were the stars of yesterday's big Apple show, the most innovative thing to be announced was undoubtedly Apple's new wireless AirPod earphones. In typical Apple fashion, they're obscenely expensive at Rs. 15,400, but a lot of intriguing technology has gone into creating them and designing the overall experience around them.

(Also see: iPhone 7, iPhone 7 Plus Price in India and Launch Date Revealed)

The AirPods look like the typical headphones that have shipped with all iPhones and iPods for the past few years, with their wires snipped off and elongated stems in place of them. Within each tiny casing, in addition to the speakers for each ear, are also two accelerometers, two microphones, optical sensors, antennas and a battery, all managed by Apple's brand new W1 wireless audio controller chip.

The W1 chip is what brings it all together. Apple execs didn't use the word Bluetooth at any point during the launch announcement, giving the impression that the W1 uses a proprietary wireless interface. However, according to information trickling out since then including on Apple's own website, the W1 does in fact use Bluetooth - there's just a lot of other communication going on as well. This means that the AirPods will be backwards compatible with older iOS devices as long as they run iOS 10.

BuzzFeed, which has published details of an interaction with John Ternus, Vice President of Mac, iPad, Ecosystem and Audio Engineering at Apple, the AirPods can in fact pair with other Bluetooth-enabled devices, a fact that wasn't quite certain at first. Details of how this is done without buttons were not specified.

According to Forbes, the W1 is based on technology created by Passif Semiconductor, a company Apple acquired in 2013. This chip is the latest addition to Apple's in-house semiconductor portfolio, complementing the A series SoCs which debuted with the original iPad and iPhone 4, and M series motion co-processors which were first used in the iPhone 5s, and S-series processors for the Apple Watch.

One of the ways in which Apple has deviated from standard Bluetooth is pairing. AirPods can work individually or as pairs. They know whether or not they're in your ears thank to their optical sensors, and audio is routed accordingly. You can use just one if all you want to do is have a voice call or invoke Siri, and your iPhone will know when that is the case. Music will be paused if you take one AirPod out of an ear, in anticipation of you needing to respond to something going on. However if you take both units out of both ears simultaneously, your iPhone will switch over to its internal speaker, thinking that's what you wanted to do.

Apple also uses your iCloud account to loop in your other Apple devices. You don't use Bluetooth to connect to an iPad or a Mac; the fact that you've already paired your AirPods with your iPhone is enough. You can then select the AirPods as the audio output for these other devices. Each of them will be able to know when another is in use, and pause playback or respond to Siri commands accordingly.

In addition to all this communication, the W1 is optimized for low power consumption. Apple promises five hours of music playback (two hours if you're making voice calls) which is impressive for such tiny devices. There's no space or weight allowance for big batteries in the AirPods. There are no LEDs to show the battery level; you have to ask Siri to read it out to you, or hold the AirPods close to your iPhone just like you did to pair them, and the information will be displayed on screen.

Apple's store page lists the AirPods as compatible with the iPhone 5 and later, iPad mini 2 and later, and iPod Touch 6th Generation, which lines up with the list of devices that will be able to run iOS 10 - as well as all models of Apple Watch. Undoubtedly there's more to learn about exactly how the AirPods work, and we'll bring you all those details when they launch in India later this year.