Apple today published a support article that explains some details about the upcoming lossless audio support for Apple Music.
Devices that support this feature include iPhone and iPad models running the upcoming iOS 14.6 update and Macs running the upcoming macOS 11.4 update.
On these devices, users can enjoy lossless audio up to 24 bits and 48 kHz. However, an external DAC is required for higher resolution files. This is because the internal DACs in iPhone, iPad, Macs, and Apple’s Lightning-to-3.5mm headphone jack adapters can only decode up to 24-bit audio at 48kHz.
The Apple TV 4K models also have the option to enable lossless audio playback with the tvOS 11.4 update. This device does not support anything beyond 48 kHz even when connected to an external receiver, which is odd.
Next up are the now discontinued HomePod and the new HomePod mini. Both devices will be able to play lossless audio in a future update.
With that we have all of the wireless AirPods including the original AirPods, AirPods Pro, and AirPods Max. Neither of these will get lossless audio as there is currently no way to transfer audio losslessly over bluetooth. These devices still only support transmission via AAC.
If you connect the AirPods Max using a cable, the audio itself can be sent to the headphones over the cable without loss. The headphones then convert the analog signal into a digital one, a process that is not completely lossless. This is also why Apple doesn’t claim that cable mode is lossless.
What Apple doesn’t clarify in this article is how lossless audio works on Windows and Android devices. One might think that the feature won’t even be available on these platforms. That probably won’t happen, but we’ll just have to wait until June to find out.
Earlier this week, Apple announced that it would make its entire library of 75 million songs available on Apple Music losslessly. Lossless audio is a method of compressing music that reduces file size while preventing data loss. For this purpose Apple uses its ALAC or Apple Lossless Audio Codec. Apple Music, on the other hand, is currently using AAC, or Advanced Audio Coding, which is a lossy technique for compressing audio.
Apple not only offers lossless audio in the standard Red Book format of 16 bits (44.1 kHz), but also up to 24 bits (192 kHz). These higher sample rates, known as high resolution audio, require a much more powerful DAC or digital-to-analog converter, hence the above limitations when playing directly on your device. The good thing is that affordable DACs are rampant these days, and you can even purchase ones with built-in amplifiers that can be plugged directly into your iPhone, iPad, or Mac via a USB adapter.
It is probably worth clarifying further that lossless audio and high resolution audio are not the same thing. You can use Hi-Res audio in lossless (FLAC, ALAC) or lossy (MQA) codecs. Likewise, lossless audio can be standard resolution (16 bit, 44.1 kHz) or high resolution (24 bit, 192 kHz). Apple currently offers AAC 16-bit 44.1 kHz and will soon offer optional ALAC 16-bit, 44.1 kHz to 24 bit, 192 kHz. Not everything will be Hi-Res, but everything will be lossless.