Understanding Bluetooth Codecs: Which One Delivers Superior Audio Quality?

Bluetooth technology is often seen as complex. Its name, derived from a Scandinavian king known for dental issues, adds to its mystique. Understanding Bluetooth also involves dealing with codecs, which greatly influence audio quality. Although codecs may seem intricate, their basics are simple once you’re familiar with the terminology.

A codec, short for “coder-decoder,” refers to the method of transmitting your audio data from the source to your Bluetooth headphones or speakers. They’re comparable to different languages—all conveying the same audio files but employing varied methods. Each codec has distinct limitations, as do the devices in use. Additionally, Bluetooth has constraints, with a maximum data transfer rate around 2 Mbps. Currently, no Bluetooth device can deliver true lossless audio without a Wi-Fi connection.

The choice of the best Bluetooth codec is situation-dependent, influenced by the devices you are using and the quality of the audio itself. To grasp the differences between codecs, it helps to understand a few key measurements, which essentially revolve around bits of data.

Bit rate: This indicates the amount of data transmitted each second; a higher bit rate usually means better audio fidelity.

Audio bit depth: The number of bits in each second of audio affects the range of sounds communicated; a higher bit depth allows for a broader dynamic range.

Sample rate (kHz): This is the frequency at which audio samples are captured every second. More frequent sampling yields more precise audio representation. A common sample rate in music is 44.1kHz, meaning 44,100 audio snapshots are taken each second.

The base codec is SBC, which is supported by all Bluetooth devices. For other codecs, compatibility varies by device. Some, like Sony’s LDAC and Samsung’s Scalable codec, are proprietary and require specific support. While AptX codecs are more universally compatible, they are still owned by Qualcomm, meaning certain versions need licenses for specific uses, such as on a PC. Below is a comparison of some common Bluetooth codecs based on raw data.

A comparison of the most common Bluetooth codecs shows the following:

However, assessing the best codec is not solely based on bit rates. A codec with a higher bit rate might still compress audio less effectively. For instance, while SBC can reach 345 kbps, manufacturers often limit it to 256 kbps to save battery. Moreover, several codecs like LDAC and AptX may adapt their bit rates according to connection quality, meaning you might not always experience their full potential. Additionally, the human ear can only discern audio differences up to a certain threshold, making it crucial to choose codecs that balance quality and battery efficiency for daily listening.

Not all devices allow users to select which codec is in use. For example, Apple products support only AAC and SBC. On Android devices, you can change codecs by accessing Developer options or using third-party applications.

Changing Codecs via Developer Options

1. Enable Bluetooth and connect your device.
2. Navigate to Settings.
3. Select About Phone.
4. Choose Software Information.
5. Tap Build Number seven times to unlock Developer options.
6. Return to Settings.
7. Select Developer Options and look for Codec.
8. Tap on Bluetooth Audio Codec and select your desired codec.

Alternatively, you might prefer an app like Bluetooth Codec Changer, which offers a more user-friendly interface. This app allows you to customize audio profiles for different scenarios, such as phone calls versus music listening, although some features may require a subscription.