Sound via Bluetooth: versions and codecs, do they affect the sound quality?
Bluetooth is a wireless technology that allows, among other things, to connect headphones or portable speakers, stereos or sound bars to your smartphone or laptop.
There are many devices on the market today with different versions of the Bluetooth protocol and with support for different codecs. What does this all mean, which version is the latest, you need to understand all of this, and most importantly for us, does it affect the sound quality in any way? Let’s take a look.
One important thing to keep in mind up front is that the Bluetooth sound technology you hear has much less impact on sound quality than the design of the device itself. If you try to test multiple headphones or wireless speakers, you will hear the obvious differences between the devices. If you test the same device, but connected with different codecs or versions of Bluetooth, the difference may not be so obvious, maybe even subtle.
Simply put, you should not base your choice solely on the Bluetooth technologies and codecs supported by the device, this is neither the first nor the second most important criteria.
Bluetooth versions
Bluetooth has improved dramatically over the years since the turn of the century, and audio compression isn’t as brutal today as it was in the days of Bluetooth 1.1 or 2.0 (when wireless headphones and earphones first hit the market. ). Let us highlight the main technical differences between the Bluetooth versions, devices with which they can be found for sale today.
Bluetooth 3.0: The data transfer rate has increased significantly (up to 24 Mbps vs. 2.1 Mbps in Bluetooth 2.0), but the power consumption has increased.
Bluetooth 4.0: reduced power consumption while maintaining a speed of 24 Mbps.
Bluetooth 4.1: added anti-crosstalk protection when working with LTE modules installed on all 4G smartphones.
Bluetooth 4.2: higher speed and improved data transmission security.
Bluetooth 5.0: range increases 4 times, speed increases 2 times.
Bluetooth 5.1: it was possible to determine the location and direction with the utmost precision.
As you can see, the new versions primarily address data rate and power efficiency issues, which rarely directly affect sound quality. However, newer versions can improve data transfer reliability, which can allow a heavier codec, such as aptX HD or LDAC, to operate at higher data rates.
Remember that for a particular version of Bluetooth to work, both devices must support it. That is, if your smartphone has Bluetooth 5.1 and the headphones are 4.2, then Bluetooth 4.2 will be used for the connection.
Audio codecs and Bluetooth
So it is not the Bluetooth version that directly affects the final sound, but which audio codec is used for sound transmission. In fact, a codec here means a complex algorithm to process (encode / decode) audio data to send it wirelessly between your devices. Using a codec is necessary because the less data is transmitted over Bluetooth, the more reliable the connection is and the less likely your headphones are to lose signal in the middle of a favorite track.
All current Bluetooth codecs are “lossy”, discarding some of the audio data, reducing the audio data transfer rate (bit rate), for example CD quality with a speed of 1411 kilobits per second at about 300 ~ 900 kbps (roughly we’ll talk about Lossy and Lossless separately next time).
Another distinguishing feature of codecs is latency. The time it takes for the digital signal processor to decode the encoded audio. Long audio latency creates problems with your timing when watching a video.
As in the case of the BT version, for the codec to work, it is important that it be compatible not only with headphones or acoustics, but also with the sound source: a phone, a player or a computer.
SBC is standard for Bluetooth. This codec can operate at data rates of up to 345 kilobits per second. While the source and destination devices can handle high bit rate audio, the audio quality is difficult to distinguish from standard AAC or aptX quality. But with the lag it can exceed 100 milliseconds or more, which creates problems with audio timing when watching a video.
