Bluetooth – the most convenient way to listen to music wirelessly. Part 2
Sound quality comparison of conventional Bluetooth coding
⬤
SBC
Bluetooth “default” transmission code
SBC (Subband Codec) is an audio codec configured for the Advanced Audio Distribution Profile (A2DP) by the Bluetooth Special Interest Group (SIG), an organization that customizes various Bluetooth standards and specifications. Since it is part of the standard, almost all Bluetooth devices support it. SBC encoding. SBC supports mono and stereo transmission, with a sample rate of up to 48 kHz, while the highest bit rate for mono is 342 kbps and stereo is 345 kbps. The sound quality is approximately equal to that of medium quality MP3. SIG announced the SBC at CES in 2020. The following LC3 (Low Complexity Communication Codec) code, in theory, has better sound quality and less distortion than SBC.
⬤
AAC
The successor to MP3
Advanced Audio Coding (AAC) is a technology jointly developed by Dolby Lab, Sony, Nokia, and other major brands. It was designed as the successor to MP3. With the same bit rate, AAC is usually better than MP3. Sound quality. Spotify, Apple Music, and KKBOX use AAC encoding to stream music, and they are also widely used on different devices and platforms such as PS3, iPhone, and YouTube. Since iPhone, iPad, etc. will use AAC as Bluetooth music streaming, most headphones, speakers, etc. Bluetooth will support AAC, and the sound quality is roughly equal to medium to medium-high quality MP3.
Bluetooth (Bluetooth) is believed to be the most familiar wireless way of streaming songs. Although the connection is quite convenient, the sound quality is slightly lower. However, with the version upgrade and Bluetooth technology, different codes have been introduced so that this convenient and fast connection method can also provide better and better sound quality.
IPhone Bluetooth streaming has always used AAC and is not equipped with encryption technologies like LDAC or even aptX.
⬤
aptX
The first “high sound quality” Bluetooth codec
aptX was also called “apt-X” before, but this encoding algorithm was invented as early as the 1980s and was eventually bought by the famous mobile phone processor manufacturer “Qualcomm”. aptX supports 16-bit, 44.1 / 48 kHz audio, bit rate up to 384 kbps, backward compatible with SBC. Since the bit rate is higher than that of SBC and AAC, it also has better sound quality.In the early years, it was the first Bluetooth music codec with slightly close to CD sound quality. However, due to the need to pay Qualcomm’s license fees, some devices, such as iPhones, are not equipped with aptX.
Bluetooth (Bluetooth) is believed to be the most familiar wireless way of streaming songs. Although the connection is quite convenient, the sound quality is slightly lower. However, with the version upgrade and Bluetooth technology, different codes have been introduced so that this convenient and fast connection method can also provide better and better sound quality.
In 2009, Sennheiser launched the first headset equipped with aptX encoding technology and also began the development of Bluetooth for high-quality wireless music streaming.
⬤
aptX-HD
Nearly “lossless” Bluetooth music streaming
aptX HD is an “evolutionary version” of aptX, which can provide a bit rate of up to 576 kbps and a bit depth of up to 24 bits and an audio stream with a sample rate of 48 kHz. Although the name has “HD”, it is still a lossy encoding method, but it can already provide almost lossless music quality, providing audio frequencies of up to 20 kHz and a dynamic range of at least 120 dB. And the encoding delay is quite small, which can be less than 5 milliseconds, which is especially beneficial for applications such as Bluetooth as hands-free communication. Of course, listening to music is helpful. In terms of high-quality Bluetooth transmission, the main opponent is LDAC developed by Sony.
Other readings:
▸ [SPILL Encyclopedia] aptX HD: The Evolution of High-Quality Bluetooth Music Listening
Bluetooth (Bluetooth) is believed to be the most familiar wireless way of streaming songs. Although the connection is quite convenient, the sound quality is slightly lower. However, with the upgrade of the Bluetooth version and technology, different codes have been introduced to make this connection method convenient and fast.
