Look at the spec sheet for any wireless earbuds or headphones and you’ll see a list of codecs: SBC, AAC, aptX, LDAC, maybe LC3. They affect how your music is squeezed down to travel over Bluetooth, but how much do they really matter? Here’s our guide to Bluetooth codecs explained, in plain English.
Quick answer
- A codec compresses audio so it fits through Bluetooth’s limited bandwidth.
- Your phone and headphones must share a codec, otherwise they fall back to basic SBC.
- LDAC and aptX Adaptive can carry more data, but are still lossy (aptX Lossless aside).
- LC3 is the new, more efficient codec for Bluetooth LE Audio.
- Fit, tuning and noise cancelling often matter more than the codec.
What is a Bluetooth codec?
A codec (coder-decoder) shrinks audio on your phone and unpacks it in your headphones. That’s needed because Bluetooth can’t carry much data. Sony says the bandwidth limit for Bluetooth audio is about 1Mbps, while hi-res audio needs around 4.6Mbps. Even CD-quality audio needs 1,411kbps, according to Qualcomm. So nearly all Bluetooth audio uses lossy compression, which throws away some data, rather than lossless compression, which keeps everything.
The main Bluetooth codecs
SBC: the universal fallback
SBC is the basic codec every Bluetooth stereo device supports. The Bluetooth standard for streaming audio, known as A2DP, makes SBC mandatory for both phones and headphones, according to the Bluetooth SIG’s A2DP requirements. If your devices don’t share a better codec, they’ll use SBC.
AAC: common on phones and earbuds
AAC is an optional codec in the same A2DP standard, and it’s widely supported. For example, Samsung lists AAC alongside SBC and its own Samsung Seamless Codec for the Galaxy Buds3 Pro. Quality depends a lot on how well the phone and headphones implement it.
aptX family: Qualcomm’s codecs
Qualcomm’s aptX site lists several versions:
| Codec | Bit depth | Bitrate |
|---|---|---|
| aptX | 16-bit | 384kbps at 48kHz |
| aptX Low Latency | 16-bit | 352kbps |
| aptX HD | 24-bit | 570kbps |
| aptX Adaptive | 24-bit | 276 to 420kbps, variable |
aptX Adaptive adjusts its bitrate to the radio conditions, so it can stay stable in busy places. Qualcomm says it’s designed to support 24-bit, 96kHz audio. Qualcomm has also introduced aptX Lossless, aimed at CD-quality 16-bit, 44.1kHz audio. As with any codec, both your phone and your headphones need to support it.
LDAC: Sony’s high-bitrate codec
LDAC is Sony’s codec. Sony says it can transmit about three times as much data as conventional Bluetooth audio, at up to 990kbps, without down-converting 24-bit, 96kHz hi-res audio. It’s still lossy compression, though, and Sony says you can lower the bitrate to suit your wireless conditions. Higher bitrates need a strong connection.
LC3: the new standard for LE Audio
LC3 is the codec for Bluetooth LE Audio, the next generation of Bluetooth audio. The Bluetooth SIG says it replaces SBC in LE Audio and provides higher quality than SBC at the same bitrate, or similar quality at a lower one. LE Audio also adds independent left and right streams for true wireless earbuds, standard hearing aid support and broadcast audio, known as Auracast.
Does the codec really make a difference?
Sometimes, but less than the marketing suggests. A higher-bitrate codec can help with detailed, high-quality recordings in a quiet room. But on a noisy commute, the seal of your ear tips and the noise cancelling usually matter more. A good pair of headphones using AAC can easily sound better than a mediocre pair using LDAC.
Bitrate isn’t everything either. LDAC’s highest setting needs a strong signal, and aptX Adaptive deliberately lowers its bitrate when the connection gets crowded, so the music doesn’t drop out.
What to check before you buy
- Check both devices. The codec only works if your phone or laptop and your headphones both support it.
- Look at your music source. Hi-res codecs make little difference if you mostly stream at standard quality.
- Gaming or video? Low latency matters more than bitrate. Look for a low latency mode, or a wireless gaming headset with its own USB dongle.
- Future-proofing? LE Audio and LC3 support is worth having, especially for Auracast sharing and hearing features.
Comparing earbuds? Read our AirPods Pro 3 vs Galaxy Buds3 Pro comparison and our guide to open-back vs closed-back headphones. For gaming, see our Arctis Nova 5X vs 7X comparison or browse the headsets in our shop.
Verdict
Codecs matter, but they’re only one part of the picture. Make sure your phone and headphones share the best codec they both support, then focus on fit, sound tuning, noise cancelling and battery life. If you’re an Android user who listens to hi-res music, LDAC or aptX Adaptive are worth looking for. For everyone else, a well-made pair with AAC will sound great. We haven’t tested codecs ourselves for this guide; it’s based on information from Sony, Qualcomm and the Bluetooth SIG. See how we test and choose products.
FAQ
Which Bluetooth codec is best?
There’s no single best codec. LDAC offers the highest bitrate, up to 990kbps, while aptX Adaptive balances quality and stability. LC3 is the most efficient for LE Audio. Your phone and headphones must both support the codec.
Is Bluetooth audio lossless?
Mostly no. Sony says Bluetooth’s bandwidth is about 1Mbps, so audio is compressed with lossy codecs. Qualcomm’s aptX Lossless aims at CD-quality lossless audio on supported devices.
What is SBC?
SBC is the basic codec that all Bluetooth stereo headphones and phones must support. It’s used when no better shared codec is available.
What is LC3?
LC3 is the codec for Bluetooth LE Audio. The Bluetooth SIG says it offers better quality than SBC at the same bitrate.
Featured image: Hykker wireless earbuds, photo by WrS.tm.pl via Wikimedia Commons, public domain.