Bluetooth Codecs Explained: AAC, AptX, LDAC and More

Being able to wirelessly connect headphones and speakers to your phone or computer is a magic many of us take for granted. It wasn’t that long ago that the idea seemed impossibly futuristic. These days, you can get true wireless Bluetooth earbuds for less than a meal at McDonald’s and BT speakers that can blow you out of the room.

But there’s more to Bluetooth than a simple wireless connection. Bluetooth is the conversation, but the codec is the language being spoken. In the early days, high-fidelity audio seemed just as impossible as wireless had only a few years before. Today, a range of codecs promises audio quality the MP3 era could only have imagined.

Not every headphone or earbud can understand every codec that’s out there. Not every source, like your phone, laptop or portable media player, can transmit every codec, either. So here’s what they all mean, what you might want to consider and — most of all — whether any of it really matters.

What’s a codec?

Starting with Bluetooth 5.2, the newer Low Complexity Communications Codec, or LC3, has become an option for manufacturers as part of LE Audio. The promise of LC3 is higher audio quality at the same, or potentially lower, bit rates. 

Most mid- and higher-end Bluetooth earbuds and headphones include additional codecs that promise the same benefits, often with a more audiophile reputation. Bluetooth SIG, the organization behind Bluetooth, even has an interesting comparison test on its website for LC3, where you can compare SBC and LC3 to the uncompressed original tracks at various bit rates.

Because it’s fairly new, LC3 is less common than most of the other codecs we’ll discuss. Remember, both the source (your phone, for example) and the headphones need to support a codec for it to work, so you might also need a new phone to get LC3 to work with your next pair of LC3-compatible headphones.

* Generally, this is the highest potential bit rate, though some implementations can be lower on specific devices. Bit rate alone is not enough to determine audio quality. For instance, AAC and SBC have psychoacoustic modeling, like MP3, so by discarding audio data, you (theoretically) can’t hear they’re capable of better apparent sound than their bit rate alone would suggest.

The next step up: AptX and AAC