What Is Lossless Audio Compression? Here’s A Quick Primer

what is lossless audio compression
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what is lossless audio compression
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Photo Credit: Kelly Sikkema

The word ‘lossless’ sounds like it describes audio with no compression used. But lossless audio compression is a thing. Here’s a quick primer.

Lossless audio formats use compression algorithms to preserve audio files in their original, recorded state. This differs from lossy audio formats like MP3, WMA, AAC, and others that compress audio using algorithms that discard bits of sound data to preserve space.

So how do lossless audio compression algorithms preserve the sound with compression? Lossless formats compress silences in sounds to near zero, reserving more space for actual audio. Some examples of popular lossless audio compression formats include FLAC, WAV, and ALAC.

But wait, isn’t WAV an uncompressed audio format? Yes and no. WAV files are just audio containers on Windows. They can contain both uncompressed raw audio files, and audio files that have been compressed using a codec. WAV is most often uncompressed, but it has poor metadata support and so it has fallen to the wayside in the digital realm.

Apple developed its own lossless audio compression technology called Apple Lossless Audio Codec (ALAC). In addition to AAC, the entire Apple Music catalog is now encoded using ALAC in resolutions ranging from 16-bit/44.1 kHz (CD Quality) to 24-bit/192 kHz. Apple says the difference between AAC and ALAC is virtually indistinguishable.

Lossless Audio Compression – Apple Music

Ready to start listening to lossless music on Apple Music? There are a couple of things you should know. First, streaming lossless audio over a cellular connection is generally a bad idea. That’s because these lossless audio files are much larger than lossy audio formats, like MP3.

You should download any lossless audio you frequently listen to on your phone to avoid data overages. You should also be prepared to have a wire attached to your phone to listen. AirPods, AirPods Pro, AirPods Max, and Beats wireless headphones use Apple’s AAC Bluetooth codec.

Bluetooth connections cannot deliver lossless listening right now. Apple says support for lossless compression is coming to the HomePod and HomePod mini in a future software update.

How to Listen to Lossless Audio on iPhone & iPad

You can listen to lossless music on any iPhone or iPad with iOS or iPadOS 14.6 or higher. You will also need some gear to get the best audio quality from your music.

  • A wired connection to headphones or speakers
  • Built-in iPad speakers
  • To listen to songs at sample rates higher than 48 kHz, you’ll need an external DAC (digital-to-analog converter)

You’ll also need to enable the lossless setting in Apple Music. Here’s how to do that.

  1. Tap Settings, then scroll down to Music.
  2. Select Audio Quality.
  3. Tap lossless and select on or off.
  4. You can customize the sample rate for both streaming and downloading audio.

Lossless for a maximum resolution of 24-bit / 48 kHz. Hi-res lossless for a maximum resolution of 24-bit / 192 kHz.

Can the AirPods Max be used to listen to lossless audio?

The short answer is yes. The lighting to 3.5mm audio cable is needed; you cannot listen to lossless audio using Bluetooth. AirPods Max can be connected to devices with the cable. Apple notes, though, “given the analog-to-digital conversion in the cable, the playback will not be completely lossless.”

Content that is not available in lossless on Apple Music includes broadcast radio, live radio and on-demand content from Apple Music 1, Apple Music Hits, and Apple Music Country. Music videos are also not supported at this time.


One Response

  1. Eric

    Small correction: WAV is not a compressed format at all, it is uncompressed. Same with AIF (or AIFF another name for the same thing).

    Lossless formats compress by between 30% and 50% (max) from the original, uncompressed file. Lossy compressed formats (like mp3 and AAC) can compress by as much as 95%.

    You can, of course, listen to lossless formats via Bluetooth, but it defeats the purpose – because Bluetooth is a lossy format itself, you are listening to a re-encoding of the lossless audio into a lossy format.