Bluetooth is a wireless technology standard that uses UHF radio waves in the ISM band of 2.4 to 2.485 GHz to enable short-range connection of devices. Traditional wired headphones rely on wires to transmit audio data, and Bluetooth headphones rely on radio waves. So many people will have a question. Does Bluetooth headphones affect the sound quality when listening to concerts?
The difference between the structure of the Bluetooth headset and the wired headset is that there is an additional Bluetooth module and battery, and the connecting wire is removed. The Bluetooth protocol has undergone multiple versions of evolution and upgrades. In previous versions of the Bluetooth protocol, due to the limitation of transmission efficiency, it was not able to achieve the transmission speed required for music listening, so it was often used for communication. Call to use.
Currently popular high-quality Bluetooth audio compression algorithms include aptX / aptX-HD, LDAC, LHDC, etc. Among them, aptX is a technology promoted by CSR. After CSR was acquired by Qualcomm, it became the proprietary technology of Qualcomm chips.
To understand the sound quality of Bluetooth headsets, we need to first understand the following concepts:
①A2DP: It is a Bluetooth audio transmission protocol, which uses a chip in the headset to stack data to achieve high-definition sound. Most Bluetooth headsets currently on the market use the A2DP transmission protocol.
②apt-x: is an audio digital compression algorithm, mainly used in the professional audio field, providing high-quality audio, some high-quality headphones will support this algorithm
③LDAC: High-quality audio codec developed by Sony, Qualcomm's apt-xhd is the main competitor.
④LHDC: High-quality Bluetooth audio codec protocol.
⑤SBC: General audio coding format, Bluetooth transmission uses SBC transmission when it does not support AAC, aptx, and now 80% is in this format.
⑥ AAC, audio encoding format, when Bluetooth supports AAC format files, and mobile phones also support AAC transmission, the sound quality is much better than SBC. The difference is heard by ordinary people. At present, Qualcomm CSR mainstream chips all support AAC format transmission.
Although the Bluetooth version is currently limited to the transmission capacity of A2DP (SBC can only provide a maximum bandwidth of 328Kbit / s at 44.1Khz), audio transmission through Bluetooth cannot be 100% restored (CD sound quality requires a bandwidth of 1.41Mbit / s) . But if you do not use SBC, but use some more advanced compression technology, you can let the audio be compressed and then transmitted through A2DP, then the sound quality can be greatly improved.
The structure of the headset, the environment it is in, and the distance between the Bluetooth devices may affect the Bluetooth signal and cause distortion in sound quality.