How do TWS headphones achieve astonishing 40db noise reduction?

Editor’s note:next few yearsThe TWS earphone market will continue to maintain rapid growth. So how big will the TWS headphone market grow in the future, and where will its "ceiling" be?

     How does semi-in-ear TWS achieve amazing noise reduction effect? This was unimaginable before, but now, with ams technology, this dream can finally come true.

     In the early morning of October 29, Apple released its new generation of TWS headphones - AirPods Pro wireless headphones, which support active noise reduction. After testing the headphones, the noise reduction effect of the semi-in-ear TWS headphones actually exceeded the noise reduction effect of Bose over-ear headphones! Everyone who tried it was shocked. Although the headset was priced at 1,999 yuan, users flocked to it, forcing Apple to continuously increase production capacity. The headset also led the trend of TWS headset noise reduction. How do semi-in-ear headphones achieve amazing noise reduction effects? Let’s take a look at the noise reduction black technology of ams, a leading manufacturer in the field of active noise reduction.

     1 Long-term hard work brings harvest

In fact, the principle of active noise reduction technology is very simple. We all know that sound is a wave, which has peaks and troughs, and these two directly determine the sound size. According to physical theory, when two waves with the same frequency and opposite phases meet, interference and superposition will occur. Therefore, as long as we design a similar wave with completely opposite status, we can reduce the intensity to the minimum and eliminate the noise.

It’s like when an object vibrates upward due to force, another force takes the initiative to suppress this wave of vibration and keep it in place. This is what active noise reduction technology does, allowing one sound wave to suppress another sound wave. This is the principle of active noise reduction. In addition to being used in headphones, active noise reduction technology is also widely used in the automotive field. A large number of mid-to-high-end models have applied active noise reduction technology.

      recently,Pierre Laboisseams, executive vice president of ams Global Sales and Marketing, accepted interviews with media such as Electronic Innovation Network and introduced ams’ active noise reduction technology.

      In fact, ams has been deeply involved in the field of noise reduction for more than ten years. The earliest ams provided analog noise reduction. In addition, ams also provides professional knowledge to headphone manufacturers to help them optimize the acoustic, mechanical and electrical aspects of product design. In 2016, ams completed the acquisition of Incus Laboratories, acquired new digital audio technology, and entered the field of digital noise reduction.

      Pierre said that the company has accumulated a lot in the audio field, and in AppleAirPods Pro wireless headphonesBefore publishing, alsoNone are specific to semi-in-earsNoise reduction solution for headphones. In June this year, amsThe company officially launched the active noise reduction chip AS3460 for semi-in-ear earbuds.

      AS3460 is a digital noise reduction solution.In addition to integrating the Augmented Hearing Engine (AHE), which is mainly used for running noise reduction algorithms, the chip also integrates the Arm Cortex-M4F MCU for signal control.Among them, the self-developed DSP in AHE is one of the core competitiveness of ams's solution. ShouldDSP is completely based on its own IP research and development, and has its unique advantages in related algorithm processing. This technology originated fromIncus Laboratories acquired earlier.

      ams has accumulated over the yearsA large number of digital signal processing noise reduction patents can help manufacturers use DSP for noise reduction. The main method is to use complex filters and related algorithm technologies to perform frequency response and phase in digital signal processing.compensate,Driven by these patented technologies, this solution achieves better performance than traditional analog noise reduction solutions.

      AS3460 can also bring automatic preset selection (APS:That is, the automatic preset scene switching) function. The specific method is that for different scenes, ams designs different filters and temporarily stores them in the chip.In actual use, APS can automatically match the best filters for different noise scenarios, bringing better active noise reduction effects.At the same time, during use, headphones using this solution can also calculate the optimal noise reduction parameters in real time based on changes in the transfer function caused by changes in leakage between the human ear and the headphones and switch smoothly, achieving a natural listening experience without POP noise.

      Pierre reveals futureams will also launch a solution with better noise reduction effect. In addition, he believes that the TWS headset line will also integrate more functions. For example, integration with biometric monitoring is also a future trend. ams has a software and hardware integrated solution in this regard, but he did not disclose more details.

      According to GFK, the global TWS Bluetooth headset market will reach US$11 billion by 2020.The latest report from Top Industry Research Institute, a subsidiary of TrendForce, also pointed out that global TWS Bluetooth headset shipments reached 78 million sets in 2019 alone, an annual increase of 52.9%! This data does not include Huaqiang’s large number of copycats.If the shipments of AirPods Pro TWS headphones are included, this number will be very amazing!Next year, Bluetooth SIG will launch a new Bluetooth standard that truly supports TWS headsets. By then, the field of TWS headsets will usher in a new round of great changes.

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