Starting with the cancellation of the 3.5 headphone jack on the iPhone, the headphone jack on high-end mobile phones has disappeared one after another, which has brought the TWS (True Wireless Stereo) headphones. Why TWS Earphones are popular?
The audio transmission between TWS earphones and mobile phones and tablets adopts Bluetooth wireless technology. Bluetooth technology was born in 1998, and the A2DP protocol (Bluetooth Audio Transmission Model Protocol) has been specified in the 1.0 version specification. On the basis of the A2DP protocol, audio coding has developed a variety of coding standards. With a simple understanding of these coding standards (algorithms, formats), consumers can choose the TWS headset that suits them.
The most basic： SBC
SBC (Sub-band coding) is a coding standard specified at the beginning of the A2DP protocol. All Bluetooth audio transmissions support this standard, which also means that all Bluetooth headsets currently on the market support SBC coding. Due to the technical limitations of SBC encoding, from the perspective of actual sound quality, it is about the same as listening to MP3 songs on a computer with wired headphones.
AAC from Dolby Laboratories
AAC (Advanced Audio Coding, Advanced Audio Coding) coding standard from the well-known Dolby Laboratories. Compared with SBC, the compression ratio of audio files encoded by AAC is higher, and the sound quality is better. Dolby’s official statement is that “AAC can accommodate a maximum of 48 channels of audio tracks, with a sampling rate of 96KHz, and can provide 5.1-channel music programs with ITU-R broadcast quality at a data rate of 320Kbps.” Before Apple’s Apple Music launched its lossless audio service, it provided music files in AAC format.
aptX acquired by Qualcomm
The aptX coding standard first came from Audio Processing Technology, which was later acquired by the British chip company CSR. In 2017, CSR was included in the chip giant Qualcomm, and the related patents of aptX belong to Qualcomm.
At present, aptX is subdivided into aptX, aptX Adaptive, aptX Low latency, aptX HD and aptX Lossless according to usage scenarios and technical standards. Among them, aptX, aptX Adaptive and aptX HD are commonly used for Bluetooth headsets. Unlike Dolby Laboratories, which only does technology research and development and formulates standards, as a chip company, Qualcomm integrates the aptX standard into its own chip software and hardware solutions. As long as you buy a Qualcomm chip, you can launch a Bluetooth headset that supports the aptX standard.
LDAC developed by Sony
Sony is a deep-rooted company in audio, and LDAC is a wireless audio coding standard developed by it, which debuted at the 2015 CES Consumer Electronics Show. Compared to aptX, LDAC has faster transfer speeds and supports higher-quality audio files.
At first, LDAC was proprietary to Sony, but later Sony and Google reached a cooperation. Android devices with Android O (8.0) and above basically already support LDAC from the software system level.
In terms of Bluetooth headsets, in addition to Sony’s own products, Xiaomi, VIVO, oppo, 1MORE, etc. have also launched Bluetooth headsets that support LDAC after obtaining authorization from Sony.
LHDC
LHDC (Low-Latency Hi-Definition Audio Codec) coding standard is developed by Shengwei Advanced Technology. Compared to LDAC, LHDC uses a different file transfer method, but both have achieved Hi-Res Audio Wireless (High Definition Audio Wireless) standard certification by the Acoustical Society of Japan. Therefore, in terms of sound quality, the sound quality of LHDC transmission is comparable to that of LDAC. Starting with Android 10, LDAC joined the Android Open Source Project.
It should also be noted that HWA (Hi-Res Wireless Audio High-Definition Wireless Audio), which is closely related to LHDC, is not a coding, but a certification standard based on the former. The properties of HWA are similar to Hi-Res Audio Wireless.
HWA certification is in charge of the HWA Alliance. The alliance was established by Huawei and the China Audio Association. Huawei is the main technology promoter, but the technology leader is still Shengwei Advanced Technology. As one of the leaders of the HWA Alliance, Huawei mobile phones are the first to support the HWA standard.
LE Audio
The Bluetooth SIG released the LE Audio standard for low energy audio last year. LE Audio can significantly improve the performance of Bluetooth audio. For example, Multi-Stream Audio brings a completely independent communication link to the headset, realizes the synchronous transmission of signals, and reduces communication delay; low-complexity communication codec (Low Complexity Communication Codec, LC3) for higher sound quality, lower power consumption and lower latency.
Because LE Audio is part of the Bluetooth 5.2 standard, devices that theoretically support the Bluetooth 5.2 standard can use LE Audio.
aptX Lossless
aptX Lossless is an audio coding standard officially launched by Qualcomm this year. This standard supports audio coding and decoding of 44.1kHz/16bit sampling specifications, and the sound quality is better than LDAC. But aptX Lossless has a series of requirements for hardware and software – Snapdragon 888 and above CPU, dedicated FastConnect chip, Qualcomm’s latest Bluetooth processor chip, Aqstic audio CODEC and Aqstic power amplifier chip, etc. The software part includes active noise reduction algorithm, true wireless, 3D audio. The popularization of aptX Lossless is still a process, and there is no Bluetooth headset that supports aptX Lossless.
Summarize
In conclusion, when both software and hardware are supported, LDAC=LHDC>aptX HD>aptX Adaptive>aptX>AAC>SBC in terms of sound quality
TWS headset recommendation
Redmi AirDots 3
The Redmi AirDots 3 uses a ring iron dual unit, equipped with a Qualcomm 3040 chip, and supports the aptX Adaptive audio standard. A single earphone can be used for about 7 hours with a full charge, and with a 600mAh charging box, the battery life can be up to about 30 hours. The control adopts a light touch type, and it can also “summon” “Xiao Ai”. Redmi AirDots 3 is available in red, blue, and white colors.
Support encoding SBC, aptX Adaptive
Edifier TWS NB2 pro
The Edifier TWS NB2 Pro is a TWS headset that focuses on noise reduction. It adopts the Hybrid composite noise reduction scheme and the ENC dual-microphone call noise reduction algorithm, and also supports the panoramic sound surround sound function. The surface of the charging box has a leather texture, and the lines of the earphone handle are sharp and tough, which are more recognizable. TWS NB2 Pro supports fast charging function, charging for 15 minutes, the headset can play for 2 hours. It adopts touch interaction, and more functions can be expanded in Edifier Connect App.
Support encoding SBC, AAC
Realme Buds Air 2
The sound cavity shell of the realme Buds Air2 earphones is treated with a frosted process, and the earphone handle is treated with an electroplating process, which supports ANC active noise reduction and environmental noise cancellation (ENC) functions. It is also equipped with a custom R2 noise reduction chip, and in game mode, the realme Buds Air2 has a minimum latency of 88 milliseconds. The headset can provide 5 hours of playback time on a single charge, and with the charging case, the headset can achieve 25 hours of all-weather battery life. realme Buds Air2 supports smart touch operation, is equipped with Bluetooth 5.2 and dual-channel transmission function, and supports IPX5 waterproof level.
Support encoding SBC, AAC
Sony WF-1000XM4
The WF-1000XM4 is Sony’s third-generation “noise-canceling bean” Bluetooth wireless headset that supports LDAC encoding and is smaller than the previous generation. At the same time, the noise reduction chip has been upgraded from the previous generation QN1e to Sony’s self-developed V1 chip, and the noise reduction effect has been greatly improved compared to the previous generation. In terms of battery life, the XM4 can last for 8 hours when noise reduction is turned on on a single charge, and it can be increased to 12 hours when noise reduction is turned off. With the charging box, it can be fully charged twice, and the cumulative battery life can reach 36 hours without noise reduction. The charging box uses a USB-C interface and supports Qi wireless charging.
Support encoding SBC, AAC, LDAC
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