1) The relationship between wireless earbuds performance and hardware and software
What factors are affecting the signal of TWS earphones?
Before 2020, the signal problem had always been among the most concerning issues for dealers and brand owners when purchasing. The signal problem directly determines the usability of TWS wireless earphones. Users want to avoid buying a pair of earphones that frequently disconnect, no matter how good the earphones are in terms of battery life, sound quality, and design.
1) Bluetooth Version
In the initial stage of the TWS earbuds market, the commonly used version of Bluetooth technology is V4.2. This version supports a maximum transmission distance of 50 meters and a maximum transmission speed of 24Mb/s. In theory, these parameters are sufficient to support true wireless. The headset runs smoothly. However, before 2020, many factories, brand owners, and distributors were still most concerned about whether the transmission of products is stable when they are producing and purchasing. I remember when a customer experiences our product, the first thing they do is cover their ears with their hands to determine how likely it is that the signal will be disconnected if it is jammed or blocked.
Why is this so?
There is always a big gap between the theoretical value and the actual application. If we compare it with WIFI technology, it may be easier to understand this problem. At present, the theoretical rate of WIFI transmission using the 2.4G frequency band can reach 300Mbps and above, but how many people have enjoyed download speeds above 20M in this environment? Factors such as the environment, the equipment's hardware, the mutual interference of signals, Etc., often lower the upper limit. The idea is very plump, but the reality is very skinny, probably so.
After the TWS earphones entered the market, it accelerated the popularization of new Bluetooth technology. Bluetooth 5.0 technology was announced in 2016, but commercial use has not been popularized. Now, Bluetooth 5.3 is gradually occupying the market, and the low-power solution to signal problems is also slowly improving.
Before the Bluetooth earphone enters the circuit board design (PCB layout), some questions must be thoroughly evaluated: Where will the Bluetooth antenna be placed? Can the earphone cavity and circuit board provide enough space for the antenna? The first-generation wireless earphone products of many brands tend to be relatively large. In addition to considering sound quality, enough space for avoidance and an excellent ideal antenna position are also important reasons. If the avoidance area is not enough, or it conflicts with other components (such as the touch area) or is located close to the skin, it will cause severe signal attenuation. For the first generation of our Card20 product, it took nearly a month to find a relatively good solution for processing the structure.
Common Bluetooth earphone antennas are divided into dipole antennas, PIFA antennas, and ceramic antennas. Strictly speaking, these antennas have advantages and disadvantages, and developers often choose a more suitable one according to product characteristics. The laser engraving antenna needs unique integration because it occupies a small space, is more suitable for compact models, and is used in some customized products.
4) Bluetooth chip
The selection of the Bluetooth chip has a significant influence on the debugging of the signal. From experience, different manufacturers and types of chips are used, and the difficulty of calling debugging will be very different. This does not mean that expensive chips are easier to debug. On the contrary, the more mass-market chips are, the easier they should be to debug.
5) Transmission mode
Compared with the primary and sub-earphone mechanisms adopted by the latest TWS earphones, it is more challenging to debug compared with the widely used pairing principles such as dual-engine and monitoring.
After 2020, users' demand for signal stability has changed from "basically available" to "not easy to disconnect in complex environments" while factories, chip manufacturers, Etc. Solve the needs of users. Bluetooth is a short-range wireless connection technology. Before the emergence of Bluetooth 5.0, the default standard distance tested by wireless headset factories was generally 10 meters. Currently, the theoretical transmission distance of Bluetooth 5.2 has reached 300 meters, and the theoretical transmission speed is 48Mbit/s. The standard has been popularized. Soon, we will listen to every high-definition audio program more freely and calmly.