On November 22 last year, Di Zhixun has released a "future of TWS headphones: Bluetooth BLE AUDIO is approaching, the mobile phone big factory will be a world? "The article, took the lead in exposed the Bluetooth Technology Alliance (Bluetooth SIG) upcoming new Bluetooth BLE AUDIO standard, and introduced the standard will act on the truth of the Radio Bluetooth Headset (TWS headset) market.

▲Ken Kolderup, Vice President, Bluetooth Technology Alliance Marketing

US local time January 6, 2020, Bluetooth Sig (Bluetooth SIG) held a media conference in the US Las Vegas CES2020, officially launched the next-generation standard Bluetooth Le Audio of Bluetooth wireless audio.

We all know that the audio of classic Bluetooth Classic wireless transmission is classic Audio, while Bluetooth Le Audio, as the name suggests, is low-power Bluetooth audio, which will not only support the same audio product as Classic Audio. And the development of the use case, also introduced an exciting new feature, which is expected to improve its performance and create new products and use cases.

Bluetooth Le Audio fully supports Bluetooth 5.1 standards and next-generation Bluetooth Le's ISOC (Isochronous) architecture, bringing innovative solutions for TWS headset markets, accelerating the TWS headset market outbreak. 

Jinhang standard KINGHELM product KH5220

Let's take a look at the new features and improvements in Bluetooth Le Audio:

First, wireless multiplex directly

There are currently a lot of TWS headphones that use the left and right headphones asynchronous transmission, mainly 2.4GHz Bluetooth signal forwarding schemes and LBRT magnetic induction.

Regardless of the forwarding scheme, it will bring a larger earphone power consumption, the battery is also exhausted, and once the main headset does not work, the secondary headset will not be used. There is also a problem of connection stability and delay.

Therefore, relative to the TWS connection scheme that needs to be distinguished, the sound signal is simultaneously transmitted to the left and right headphone units, and the protocol may not only effectively avoid the electric wave loss, but also reduce the delay and Improve connection stability and bring a better user experience.

The TWS connection scheme of the previous non-division of the secondary headphones mainly include: Apple's listening scheme and Double connection scheme adopted by Qualcomm. At the same time, there are some other chip vendors on the market to begin a different approach, through other technical solutions to achieve the "double hair" of the non-divisional secondary headset.

However, there are several problems, one is a patent issue, relatively, Apple, Qualcomm and other audio technology majors have more technical patents, other similar programs or other similar programs or There will be patented hidden dangers; another question is that each chip manufacturer is fighting, and there is no uniform Bluetooth audio transmission standard that can be unshalful, which will cause TWS earphone compatibility, because many programs It is difficult to support the mobile phone, especially if it is more difficult to compatibility with the chip platform. For example, the TWS headset of the Qualcomm Slip, may not be compatible with mobile phones that use Apple or Huayi Chip.

Obviously, these problems hinder the development of the TWS headset market.

As is the case of such a previous Iz, Bluetooth Le Audio has joined the new multi-stream audio function to achieve a single audio source device and one or more audio receiving devices. Multi-and independent audio string streaming.

That is, Bluetooth Le Audio not only completely solves the standard problems and compatibility issues of TWS headphones, and an audio source can even connect multiple wireless audio acceptance devices.

HEARING AID WORKING HO Working Group (HEARING AID WORKING Group Chairman Nick HuNN) said: "For real wireless incoming earphones, developers will be able to use multi-stream audio functions to improve performance. For example, Multi-string audio can provide a better stereo experience, making the voice assistant service more seamless and makes switching between multiple sound source devices more smooth. "

Second, support broadcast audio

In addition, Bluetooth Le Audio also adds broadcast audio (Broadcast Audio), allowing audio source devices to broadcast one or more audio streams to unlimited number of audio receiving devices. The joining broadcast audio technology has also provided an important new opportunity for innovation, including enabling new Bluetooth use case "audio sharing".

According to reports, Bluetooth audio sharing based on radio audio technology can be personal or location. Through Bluetooth audio sharing, people will be able to share Bluetooth audio experiences with others; for example, sharing music in smartphones with family and friends. Through the location-based audio sharing, there are public places such as airports, bars, gymnasiums, cinemas and conference centers.

The Bluetooth Technical Alliance Board of Directors, the head of the BOSE, said: "Location-based audio sharing features are expected to change our experience environment. For example, even in public places, even in silent mode, it is still possible to broadcast audio. People receive TV audio signals, and the scenes such as theater and lecture halls will be able to share audio, and can even provide helpful visitors, while also have multilingual. "

Stefan Zimmer, Secretary-General of the European Listening Instrument Manufacturer Association, said: "Le Audio will drive the development of Bluetooth hearing aids, thus bringing all the benefits of Bluetooth audio to increasing hearing loss .le Audio will become the most important of hearing aids and hearing aid users. One of the progress. "

Ken Kolderup, vice president of Bluetooth Technology Alliance Marketing, also, also, said that the design of Le Audio specification fully supports hearing aid development standards. Kolderup expects that the LE Audio standard product will appear in the second half of 2020 and integrate the Le Audio listening options in the field in the next three years.

Third, the new audio code decoder LC3

For TWS headphones, mainly used to receive audio, and the sound quality effect is directly affected by the user's experience. The audio codec format that is most widely used in classic Bluetooth is most widely used in classic Bluetooth.

Among them, SBC is a Bluetooth audio transfer protocol enforcement code format, all Bluetooth audio chips support this protocol, but this code rate is only 320kbps, and because the Bluetooth transmission intermediate device is required, each transcoding will lose details. Therefore, the hearing sensation caused by the SBC will be a lot more than the original MP3.

In contrast, Apple's main push AAC and Qualcomm CSR's APTX, Sony's LDAC is better, but not other Bluetooth audio chip manufacturers want to use, the same terminal TWS headset brand manufacturer, want to provide more Good sound quality, mostly only select high-pass chip solutions.

Therefore, for other TWS headset brand manufacturers, in addition to Qualcomm, the high-quality Bluetooth audio technology solutions can be selected is limited, and this also hinders the TWS earphones in sound quality.

The BLUETOTH LE AUDIO released this time is integrated with new high-quality, low delay, and low power audio decoder LC3.

According to reports, the sampling rate of LC3 is: 8, 16, 24, 32, 44.1, 48kHz, bit rate: 16-320 kbps, frame length: 7.5, 10 ms. With high quality characteristics, it can provide significant flexibility in low data rate conditions, which will better trade between key product properties such as sound quality and power consumption during product design.

According to the standard stereo measured data displayed by the Bluetooth Technology Alliance and Fraunhofer IIS (LC3 Code Technology Contributors), LC3 will provide higher sound quality effect, even in Bit, based on the SBC codec of Classic Audio. The rate of high sound quality can be maintained if the rate is reduced by 50%.

Fraunhofer IIS Communication Audio Audio Department Manfred Lutzky said: "Developers will be able to take advantage of this advantage, create battery life more lasting products, or optimize by using smaller sizes by using smaller sizes Product shape design size. "

It is worth mentioning that Fraunhofer IIS from Germany is not only the LC3 codec contributor of this Bluetooth Le Audio, but also the contributor of MP3 / AAC technology.

In addition to the LC3 of the Bluetooth Le Audio mandatory codec, Fraunhofer IIS also launched a standardized scheme LC3PLUS with more advantages on the basis of LC3.

Fraunhofer IIS China Representative Office Technical Sales Manager Zou Wei told Core Zhixun: "LC3PLUS is an extension version of LC3, which also has high transmission robustness, extremely low delay and high resolution audio transmission on the basis of all of LC3. ability.

1. In order to improve robustness, LC3PLUs contains very high performance packet loss hidden algorithms, as well as forward error correction schemes such as channel coding or redundant frame modes.

2. The codec can operate in several low delay modes, such as 2.5 ms frame length delay can be as low as 5 ms.

3, LC3PLUS's special high-resolution audio mode can provide high quality audio with 24bit and 96kHz, which is very suitable for high-quality wireless headphones and high quality game headphones. Open standard audio codecs.

According to reports, the current ETSI (European Telecommunications Standardization Association) has been standardized to TS 103634, and the DECT brings ultra-wideband voice / audio quality due to the incorporation of the 2019 DECT standard. Its broadband capacity is twice the previous standard. LC3PLUS channel coding designed for DECT channel characteristics allows LC3PLUS payloads to be transmitted on a distant DECT channel, even if the phone is far from the base station, it is also possible to interrupt.

Zou Wei said to Core Zhixun: "Although LC3 has become a mandatory codec of Bluetooth Le Audio, you can get LC3 related SDK for Bluetooth through us. Manufacturers who have higher requirements for sound quality can also choose LC3PLUS. "

Zou Wei said to the core Zhixun: "LC3 standard is expected to be released in the first half of 2020, Fraunhofer IIS will provide development code for the industry in the first time. CADENCE and SYNOPSYS have launched related products. And for sound quality, delay, and transmission Higher requirements manufacturers also welcome LC3PLUS. "

Summary: 

As the previously introduced, the main secondary headset exists in many TWS headphones, the sound quality, poor compatibility, poor compatibility, power consumption, which restricts the improvement of the TWS headset experience, and also restrict the TWS headset industry. developing. The new Bluetooth Le Audio standard has been largely solved in a large extent. Therefore, there are also many chip vendors to follow up.

According to reports, the current Bluetooth chip large factory such as Airoha (Dial), Dialog, Gaittong Technology, Microchip, Nordic, Qualcomm is about to introduce Bluetooth chips that support Bluetooth Le Audio standard. It is worth mentioning that on the CES2020, Hunting Technology also works in a technological, first demonstrating the Bluetooth Le Audio solution applied to TWS true wireless headphones.

However, it should be pointed out that even if the manufacturer has introduced a TWS headset based on the Bluetooth Le Audio standard, it is also necessary to transmit the Bluetooth Le Audio standard. Therefore, the size commercial time point of the BLUETOTH LE AUDIO solution should be in the second half of this year. .

 
Jinhang standard KINGHELM product KH6010

At present, the replacement of TWS headphones for traditional low-end wired headphones has become a general trend, especially in the power of upstream chip manufacturers and many mobile phone models, TWS headphones have been rapidly improved, cost Also accelerated down.

Core Zhixun still insists that the previous judgment, we believe that the future TWS headset is expected to be a standard accessory for smartphones, and fully replacing the wired headphones comes with the previous smartphone "in box". This also means that the TWS headset market still has nearly 10 times grew space. With the launch of Bluetooth Le Audio standards that can effectively solve many experience problems in TWS earphones, this process will undoubtedly accelerate this process. At the same time, the application of the new audio broadcast function of Bluetooth Le Audio will further expand the application range of TWS headphones.