It's time to spread the knowledge of Bluetooth version with everyone. Please read this article in the correct posture: While listening to the music you think is beautiful with the Bluetooth speaker, while clasping your feet, don't forget to read and think. There is actually no difference between 2.0 and 2.1. The transmission speed is basically the same, but the power saving module is improved and the distance is a little longer.
EDR stands for Enhanced data rate, which is the abbreviation of enhanced data rate in Bluetooth technology. Its feature is to greatly increase the data transmission rate of Bluetooth technology to 2.1Mbps, which is three times that of current Bluetooth technology. Therefore, in addition to lower power consumption for more stable audio streaming, it can also make full use of the bandwidth advantage to connect multiple Bluetooth devices at the same time. Connect a mobile phone and a computer while connecting the Bluetooth speaker.
In the Bluetooth 2.0 specification, EDR appears as a supplement. It correctly defines the change in modulation technology and additional packet types, which enables it to transmit at a rate of 3MBPS. Therefore, what we usually see is "Bluetooth Core Specification version 2.0 + EDR".
The actual situation is that there is currently no Bluetooth application that requires more than 1MBPS for transmission. Even for high-quality stereo data streams, it must use subband codec; SBC codec, which requires 345KBPS at most. Therefore, the stereo sound of Bluetooth speakers is not so "three-dimensional".