When using the Bluetooth headset, found that the computer's playback device shows two modes (as shown in the figure below), Stereo mode sound normal, and tuned to the Hands-Free AG Audio mode under the sound band is much narrower and poor sound quality, typical of the phone sound, the following specifically say the difference between the two modes.
- stereo=stereo (good sound quality, can only listen to songs)
- hands free = hands-free (poor sound quality, microphone available)
StereoThe device is referred to in Bluetooth terminology as an "Advanced Audio Distribution Profile", or A2DP, and is designed to transmit high-quality two-channel stereo sound in one direction. This simply means that the sound quality is higher (as opposed to "Hands-free" mode).
Hands-free ("Hands-free")The device corresponds to "Hands-Free Profile" (HFP) or "Headset Profile" (HSP), respectively.
They are both older than A2DP, and were first used to design for phone calls (two-way mono sound, limited frequency response, optimized for voice only). Hands-free (especially HSP), was designed to optimize headset power consumption. For wireless Bluetooth headsets (speakers), battery power is generally very limited due to physical size limitations, so it can be simply understood that hands-free mode is more power efficient. But the sound quality is worse.
Therefore, when using a Bluetooth headset, it is recommended to use theStereo。