​Bluetooth speakers can't talk about sound quality?

- May 11, 2018-

What is the impact of bluetooth audio transmission on sound quality?

When it comes to factors that affect the sound quality of a bluetooth stereo, the first thing many people think about is the loss of bluetooth audio transmission.

In fact, as early as the bluetooth 2.0/2.1 era, the speed of bluetooth transmission has reached 2.1 Mbps, enough to meet the transmission of high-quality audio. But when it comes to bluetooth audio transmission, whether it's early bluetooth 2.0/2.1 or today's ubiquitous bluetooth 4.0, the same A2DP protocol is used.

Because A2DP agreement greatly limits the transmission bandwidth, audio signal the need for effective compression in order to ensure real-time broadcast at the receiving end, which has the bluetooth audio equipment in a variety of decoding scheme.

There are three kinds of bluetooth audio encoding schemes: SBC, AAC and apt-x. SBC is old, but still is the most common bluetooth audio codec scheme, AAC and apt - X is relatively new, on SBC scheme was improved, sound quality is better than SBC scheme in theory, the AAC scheme is mainly used for the iPhone apple devices, such as apt - X scheme is in vivo, samsung and other brands of mobile phones are common.

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It is important to note that although the apt - X describes himself as a "CD" audio codec scheme, but in actual use, apt - X is better than the old SBC, but there are still certain distance "CD" transmission distance. In addition, apt-x needs to be supported by the launch equipment and the playback device. If you want to use apt-x, you need to check whether the speaker supports the sound box before buying the bluetooth speaker, except for a mobile phone that supports apt-X.

If the three encoding schemes are to be named, apt-x is better than AAC over SBC in normal performance, and there is still a significant gap compared with the traditional wired audio transmission. But if you put the gap in a small bluetooth speaker, the effect on sound quality is far less theoretical.

We can be a simple test to prove that most of the bluetooth speakers have AUX linear input interface (3.5 mm headphone jack), we can use the double line 3.5 mm audio output in the mobile phone or Hi - Fi player analog audio input directly to the bluetooth speaker, and use a bluetooth transmission quality difference were compared.

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In most cases, the difference in sound quality is often small or even indistinguishable in the two modes. To Bose Soundlink Mini (first generation), for example, after changed into linear output, voice will retain more details of high frequency, low frequency is also becoming less "mouth", the sound will become more "clear", but the sound is still relatively limited, and there will be no "autoart audi" feeling. The sound quality of the stereo is often smaller than that of bluetooth.

In short, in a portable bluetooth speaker, bluetooth audio transmission does have an impact on sound quality, but it is not enough to become a bottleneck.


Xinyuanchuang company is a high quality company specializing in 3C accessories. The main products include bluetooth speaker, bluetooth headset, USB flash drive, etc.