Quality of voice recording with Android Bluetooth
Bluetooth makes the mobile phone more efficient with the wireless connection, the tedious wired connections for audio devices are no longer necessary. Little earbuds allow you to be completely hands-free for answering phone calls or listening to your favorite music.
Modern high-end Bluetooth devices support AptX, a proprietary audio codec that offers high-quality audio that preserves more of the audio’s full range of frequency. It is faster to encode and decode and AptX HD is an even higher-quality with 48kHz audio.
Advanced Audio Distribution Profile (A2DP) is one of the oldest Bluetooth audio profile. It is the default for streaming audio over Bluetooth that supports high-quality stereo audio. It also supports other methods of compression and encodings like MP3, AAC, and ATRAC and it doesn’t need to re-encode in sub-band coding (SBC). With A2DP, the maximum audio bandwidth is 728kbit/s but due to “lossy” compression in the SBC, the reality of the audio quality is considerably lower, somewhere in the range of 256kbit/s at 48 kHz.
Audio Recording using Bluetooth device
Audio recording from a smartphone’s mic or any other wired headset gives a high-quality sound without any loss in the information. With the introduction of Bluetooth wireless devices that are often used for audio recording, the quality is not good enough. This Bluetooth recorded files sounds like old recorded audio and is not as clear as modern wired microphones.
The main reason for the poor recording quality is that in recording mode the Bluetooth switches to 8kHz low-quality mono configuration, as compared to 48kHz stereo. Due to this switching to lower bandwidth a significant data is lost which ultimately results in poor audio.
Bluetooth has 79 channels for different devices but a Bluetooth audio device has only two channels. in bidirectional communication, format mic takes up 1 channel leaving a single channel for headphones. This means that when the mic is being used the audio quality suffers.