Bluetooth Audio Codecs Explained: AAC, aptX, LDAC and LC3

Bluetooth can’t send music at full quality, so your phone compresses it first using a codec. Both phone and earbuds must support the same codec, otherwise they fall back to the basic one. Here’s what the names on the box mean.

The main codecs

• SBC: the mandatory basic codec every Bluetooth audio device supports. Fine, but the least efficient.
• AAC: the codec Apple devices use. On iPhone it performs very well, and it’s why AirPods sound good on iPhones. Android support and performance vary by phone.
• aptX family: from Qualcomm, common on Android phones with Snapdragon chips. Variants such as aptX Adaptive adjust quality and latency to conditions.
• LDAC: developed by Sony, supports higher bitrates. Built into Android, and popular with Sony headphones. At its highest setting, the connection can be less stable in crowded places.
• LC3: the codec of Bluetooth LE Audio, designed to sound better than SBC at lower bitrates and use less power. It also enables Auracast broadcast audio.

iPhone vs Android

iPhones use AAC and don’t support aptX or LDAC. That doesn’t make iPhone audio bad: AAC on Apple devices is excellent. Android phones support a wider range of codecs, depending on the manufacturer and chip.

Can you hear the difference?

For most people, in most listening situations, the earbuds’ tuning, fit and noise cancellation matter far more than the codec. On a noisy bus, no one can hear the difference between AAC and LDAC. Codecs matter more for critical listening in quiet rooms with high quality files.

Latency for gaming and video

Codecs also affect delay. Most video apps correct for it, but in games you may notice lag. Gaming modes and low latency codec variants help.

The takeaway

Buy earbuds that suit your phone’s ecosystem and your ears. iPhone users should look for good AAC performance. Android users can benefit from aptX or LDAC if their phone supports them.

Sources

• Bluetooth SIG, LE Audio and LC3
• SoundGuys, Understanding Bluetooth codecs