Sidebar 1: On Bluetooth
One reason I green-lighted Rogier van Bakel's review of the Apple AirPod Pro 2 is that, while Bluetooth audio has a somewhat dubious past, its future seems promising (footnote 1). Bluetooth is a protocol that enables wireless audio and much else. Operating within the Bluetooth standard, or riding on top of it, are codecs for coding audio including SBC (the basic, default Bluetooth audio codec), AAC (preferred by Apple and used by YouTube), LDAC (from Sony), and several varieties of aptX (standard, HD, Adaptive, Lossless, and so on).
Sony and Qualcomm have led the push for better Bluetooth audio quality, with LDAC and aptX, respectively; both have versions capable of lossless audio or something very close. But LDAC and aptX are proprietary codecs, and Apple is unlikely to embrace them—ever. Apple, with AAC, has long seemed to settle for a rather low audio-encoding standard.
So why review an Apple product? Because they're the market leader at both ends of the chain, with iPhones and AirPods, respectively. If Stereophile is going to investigate a mass-market technology, we might as well focus on the "mass" part.
Perhaps it's promising that with the AirPods Pro 2, Apple chose to implement Bluetooth 5.3, an advanced Bluetooth codec that incorporates something called LE Audio, adopted in 2020 as part of Bluetooth 5.2. LE stands for "low energy," from its roots in improving hearing aids, where energy efficiency is imperative. Energy-saving technologies are also useful for true-wireless headphones? like the Apple AirPods Pro 2—but for our purposes the most important thing about?LE Audio is LC3, short for "low-complexity communications codec." LC3 is said to be?a big improvement on so-called Bluetooth Classic audio.
Is this, then, the magic bullet for Apple's Bluetooth products, the key to better sound? I could be wrong about this, but I'm thinking: probably not. LC3 is a huge improvement in some ways—latency, energy efficiency—and tests show that it sounds far better than SBC, the basic, built-in Bluetooth codec. Yet, it may not even equal AAC in audio quality at a given bit rate. If Apple implements LC3, you should see better battery life and experience less annoying latency when watching movies with headphones, but there doesn't seem to be much in it for audio quality.
Perhaps it's worth remembering that Apple was once reviled for the lack of accessibility in its products—until all the sudden, one day, they were the best. Apple could, at one of its big annual events, announce a new version of AAC that supports lossless audio. One way or another, I'd be shocked if Apple didn't have a plan for bringing its audio hardware up to the standard of its software, specifically Apple Music's lossless streams. Fingers crossed.—Jim Austin
Footnote 1: The other reason: Audiophiles fly on airplanes and, in cities, take subways, and when they do, they like music.
Footnote 1: The other reason: Audiophiles fly on airplanes and, in cities, take subways, and when they do, they like music.
