When you stream music or take a call over Bluetooth, your phone and headphones use a codec, a small piece of software that compresses and decompresses audio data so it can travel wirelessly. The codec you end up using affects sound quality, how quickly the audio reaches your ears, and even how long your battery lasts. Understanding the main Bluetooth codecs helps you make sense of what your gear can do and why two pairs of headphones can sound different with the same phone.
What a Bluetooth codec does
A codec, short for coder-decoder, takes a digital audio signal and shrinks it so it can be sent over a Bluetooth connection without using too much bandwidth. On the receiving end, the codec unpacks the data and turns it back into sound. The amount of compression and the way the codec handles that process influence how much detail is preserved, how much delay (latency) is introduced, and how much energy the wireless radio consumes.
According to the Bluetooth SIG, the SBC codec is included with Classic Audio. Optional codecs can step in when both the source device and the headphones know how to speak them, often delivering clearer sound or lower latency.
LE Audio and the LC3 codec
The Bluetooth SIG introduced LE Audio as the next generation of Bluetooth audio, running on the Bluetooth Low Energy radio rather than the Classic radio. A central piece of LE Audio is the Low Complexity Communications Codec, or LC3. The Bluetooth SIG states that extensive listening evaluations have shown LC3 provides improvements in audio quality over the SBC codec included with Classic Audio, even at a 50% lower bit rate. That efficiency gives developers room to make trade-offs: they can use the power savings to design products with longer battery life or, when current battery life is enough, shrink the form factor by using a smaller battery.
LE Audio also brings Multi-Stream Audio, which allows multiple independent, synchronized audio streams between a source and one or more sink devices. The Bluetooth SIG explains that this can improve stereo imaging on truly wireless earbuds, make voice assistant interactions more seamless, and smooth out switching between multiple source devices. In addition, LE Audio adds support for Bluetooth hearing aids, opening up wireless calling, listening, and watching to a growing number of people with hearing loss.
If you want to explore how codec choices interact with other headphone features, our Headphone Technology Explained article covers ANC, spatial audio, and more. You can also see how battery life figures into the picture on our Battery Life page.
LDAC: high-resolution audio over Bluetooth
Sony developed LDAC as a way to transmit more data over a Bluetooth connection. According to Sony’s LDAC product page, LDAC can send audio at a maximum bitrate of 990 kbps,. This higher throughput allows LDAC to carry High-Resolution Audio content and meet the requirements of the “Hi-Res Audio Wireless” logo at the 990 kbps transfer rate.
LDAC includes a “Best effort” mode that automatically adjusts the bitrate depending on network conditions. Sony says the bitrate changes among 330 kbps, 660 kbps, and 990 kbps to keep the connection stable even in challenging wireless environments. Because LDAC is a software codec, it can be added to a wide range of devices. Sony contributed the LDAC source code to the Android Open Source Project, so many smartphone manufacturers can include LDAC playback support, though a license from Sony is required for sink devices like headphones.
For a broader look at how wireless and wired paths compare, visit our Wired vs Wireless guide.
aptX and Snapdragon Sound
Qualcomm’s aptX site focuses on its Snapdragon Sound technology. The company’s aptX page now highlights Snapdragon Sound technology, which is designed to bring together several Qualcomm audio technologies across phones and earbuds. Qualcomm describes Snapdragon Sound as supporting lossless and high-resolution music streaming, super wideband voice for clearer calls, and ultra-low latency for gaming, all while maintaining glitch-free audio even in busy wireless environments.
While the page does not break out individual bitrate figures for each aptX variant, the emphasis on low latency makes these codecs particularly relevant for gamers and anyone who watches video and needs the audio to stay in sync with the picture. If gaming is your primary use, our Gaming section can help you think through other features that matter alongside the codec.
Why codec compatibility matters
A codec only works when both the source device and the headphones support it. If your phone can send LDAC but your earbuds only understand SBC and AAC, the connection will fall back to a codec they both share, often SBC. The same rule applies to aptX and LC3. This means that before you assume you are getting the highest-quality stream, you need to check the specifications of both ends of the link.
Manufacturers usually list supported codecs on the product page or in the user manual. Steps differ by model, so following your own device’s documentation is the most reliable approach. Our Compatibility page walks through what to look for when matching headphones with phones, computers, and other sources.
Auracast broadcast audio: sharing your sound
Auracast broadcast audio is a new Bluetooth capability that is part of LE Audio. The Bluetooth SIG describes it as a way for an audio source to broadcast one or more streams to an unlimited number of nearby sink devices, without the need for traditional pairing. This opens up several scenarios: you can share music from your phone with a friend’s earbuds, unmute a silent television in a public lounge, or use it as an assistive listening system in theaters and lecture halls.
Joining an Auracast broadcast is designed to be straightforward. The Bluetooth SIG outlines three methods: searching for available broadcasts much like you scan for Wi-Fi networks, scanning a QR code displayed at a venue, or tapping an NFC tag to connect. Because Auracast is built on LE Audio, devices need to support the new standard to take part. For a deeper dive into the underlying technology, see our Bluetooth Codecs category page.
How to check which codecs your headphones use
Start by looking at the specifications on the manufacturer’s website or the printed materials that came with your headphones. The exact steps vary by operating system and device model, so consult the support pages for your specific phone and headphones. If you are comparing models, our Connectivity page explains how different wireless features are documented.
Frequently asked questions
Do all Bluetooth headphones support LDAC?
No. LDAC must be supported by both the source device and the headphones. Sony’s LDAC page notes that a license is required for sink devices, and while many Android phones include LDAC playback, not all headphones have the necessary software.
What is the difference between LE Audio and Classic Audio?
According to the Bluetooth SIG, Classic Audio operates on the Bluetooth Classic radio, while LE Audio runs on the Bluetooth Low Energy radio. LE Audio introduces the LC3 codec, Multi-Stream Audio, and Auracast broadcast audio, and it adds support for hearing aids.
Can I use Auracast with any Bluetooth headphones?
No. Auracast is a feature of LE Audio, so both the transmitter and the receiver need to support the new standard. The Bluetooth SIG explains that joining an Auracast broadcast will be possible through searching, scanning a QR code, or tapping an NFC tag, but only on devices built for LE Audio.
For more details on Bluetooth codecs and how they affect your listening experience, visit our Bluetooth Codecs page.
