What Is Bluetooth A2DP?

By John Granby

i Ray Robert Green/Demand Media

Bluetooth is a wireless technology that is most often associated with mono audio headsets used for phone calls. However, Bluetooth is fully capable of carrying a lot more than just phone audio and is a popular wireless solution for stereo headphones as well as portable external speakers.

Definition of Bluetooth A2DP

i Ray Robert Green/Demand Media

The Advanced Audio Distribution Profile (A2DP) is the technology behind what's popularly known as Bluetooth Stereo Audio. Bluetooth A2DP enables a device such as a smartphone to connect wirelessly to a Bluetooth stereo headset and transmit music or other audio, as from a video. By default, the technology decodes audio from its native format (such as MP3 or AAC) and transforms it into a format that is more appropriate for Bluetooth's bandwidth. True audiophiles may notice some loss, but the quality of speakers used in stereo Bluetooth headsets typically does not allow for the loss to be noticed by most users. Most smartphones today are capable of connecting to A2DP devices and transmitting audio.

Types of Devices

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Manufacturers have used Bluetooth A2DP in both mono and stereo headsets. In mono headsets, however, the stereo aspects of A2DP aren’t used. Dual-speaker devices such as Bluetooth stereo headphones and external speakers are the most widely used devices for Bluetooth stereo audio playback. These devices can connect to your smartphone or computer to play audio from a music playlist or a movie you’re watching. A2DP can also transmit high-quality voice from a microphone, but this application is not widely available in consumer devices. A2DP devices with microphones still use a mono audio codec best-suited for high-quality phone audio and meant for a different Bluetooth profile altogether.