Latest AirPods Beta Hints at Call Sound Quality Upgrade Coming Later This Fall

The LC3 codec in the new beta AirPods firmware is not used for music. It’s strictly for the Handsfree Profile (HFP), which covers audio calls.
AirPods Pro Credit: Yasar Turanli / Shutterstock
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During the iOS 15 beta cycle last summer, Apple began offering beta versions of its AirPods firmware to developers for the first time. That’s being repeated this year, and while we don’t recommend taking the risk of installing these early releases on your main set of AirPods, the beta firmware gives us a peek into some things Apple is working on for its wireless earbuds and headphones.

The AirPods beta firmware closely follows the development of iOS 16 and Apple’s other operating systems. It will undoubtedly help power some of the new features coming to the iPhone, iPad, and Mac this fall. The most significant of these is Personalized Spatial Audio; although this already works with the stock AirPods firmware, Apple is undoubtedly tweaking it to make it sound even better.

Apple typically doesn’t say much about what’s new in its AirPods firmware updates, and this developer beta is no exception. The sparse release notes simply say that the latest beta improves Automatic Switching and fixes some bugs.

AirPods beta firmware for Apple Developer Program members enables development of features on iOS and macOS for AirPods. This program also enables debugging of issues by Apple with on-in log collection. This release includes improvements to Automatic Switching and various bug and stability fixes.Apple

Notably, Apple is releasing beta versions of the AirPods firmware to developers so they can build and test features in their own apps for both iOS and macOS. The beta firmware is limited to the second- and third-generation AirPods, AirPods Pro, and AirPods Max.

The process of installing AirPods beta firmware remains unchanged from last year, including the critical caveat that there’s no going back. If this messes up your AirPods, you’re stuck on that version until the next update comes along.

In other words, you really shouldn’t do this unless you have a spare pair of AirPods lying around that you’re willing to sacrifice to the beta gods. While it’s unlikely the beta firmware will permanently “brick” your AirPods, that’s still a possibility; however, it could easily render them unusable until the final firmware release lands in the fall.

Better Bluetooth Quality

One of the exciting things about the AirPods beta firmware is what it hints at for Apple’s next generation of AirPods.

Last month, leaker ShrimpApplePro and a Twitter user who goes by the name george (@marajobsession) discovered references to the higher-quality LC3 Bluetooth codec in the first AirPods beta.

LC3, which is short for Low Complexity Communication Codec, is a successor to the baseline SBC codec that’s been used in Bluetooth headphones since nearly the beginning; it offers higher quality and consumes less power since it’s the default codec used by the new Low Energy Audio (LE Audio) spec that was introduced in early 2020.

The practical upshot is that you’ll get better sound quality at lower bit rates. Further, despite being part of the Bluetooth 5.2 spec, which no current AirPods support, early adopters have already discovered that it offers a noticeable improvement in the quality of audio calls.

This is because the LC3 audio codec doesn’t specifically require Bluetooth 5.2 to produce better audio quality. It’s the Low Energy aspect — LE Audio — that’s a feature of the latest Bluetooth spec.

While this means the AirPods Pro 2 will likely adopt Bluetooth 5.2, resulting in some nice battery life improvements, it’s entirely possible that Apple could also push a Bluetooth 5.2 spec update to its existing AirPods. It wouldn’t be the first time it’s done such a thing; the iPhone 6, iPad Air 2, and iPad mini 4 quietly got a Bluetooth 4.2 update in 2015.

Apple also has a history of coloring a bit outside the lines when it comes to audio standards, as george points out on Twitter.

However, no actual magic is required to support the LC3 audio codec, as that fits within the Bluetooth 5.0 spec, and there’s been no evidence yet that LE Audio is available in the new AirPods firmware.

Is LC3 Lossless Audio?

To be clear, this is not the Lossless Audio codec that many have been hoping for. Apple is reportedly still hard at work on that, but it’s almost certainly something Apple is cooking up on its own.

The LC3 codec maxes out at 345kbps, which is a bit better than Apple’s 256kbps AAC codec, but it’s still far from even the 960kbps peak offered by the “near-lossless” LDAC, much less the 1,411kbps of true lossless codecs like FLAC and Apple’s Lossless Audio Codec (ALAC).

LC3 is also a “scalable” codec, meaning the bitrate can vary depending on several conditions. LC3 can get as low as 160kbps when dealing with interference or range. That puts it well below AAC, which always operates at a steady 256kbps.

In practical terms, this means it won’t necessarily be all that much better than AAC, which the AirPods already use for music. From what we’ve seen so far — and the testing I’ve done myself — the LC3 codec in the new beta AirPods firmware is not used for music. It’s strictly for the Handsfree Profile (HFP), which covers audio calls.

Apple is unlikely to adopt LC3 for music for two reasons: Firstly, it doesn’t offer a meaningfully higher bitrate. However, more significantly, it would also require transcoding of audio content. Apple Music either plays natively in AAC or gets efficiently transcoded from Lossless to AAC using hardware encoding chips built into the iPhone and other Apple devices.

Besides that, Apple is working on a proper lossless codec for music, so there’s no sense wasting time only marginally to bridge the gap with LC3. Codecs like Sony’s LDAC and Qualcomm’s aptX Adaptive already scale to much higher bitrates. While Apple isn’t about to get in bed with Sony or Qualcomm to license those, there’s already a scalable extension to AAC known as SLS (Scalable to Lossless) that can provide similarly near-lossless quality.

However, since Apple could have easily adopted AAC-SLS already if it wanted to, the fact that it hasn’t means there’s a good chance it’s working on something even better: true lossless audio for its premium wireless headphones.

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