Overview
With the increasing popularity of TWS earphones in the market in recent years, major earphone manufacturers have begun to develop their own Active Noise Cancellation (ANC) technology to provide users with a better user experience.
ANC technology analyzes the sound wave characteristics of noise and then sends inverse sound waves to neutralize the noise, thus eliminating it. Its advantage lies in its significant suppression of low-frequency noise; by effectively isolating low-frequency noise, it reduces the impact of noise on hearing and health. Generally, the effective frequency range for ANC noise cancellation is between 50Hz and 2kHz. For noise exceeding 2kHz, manufacturers can address it through passive noise cancellation methods via headphone structural design and material selection.
The noise cancellation effect of ANC headphones is determined by two factors: the design of the filter circuit and the noise cancellation gain values. The filter circuit design is finalized during the R&D phase and will not be changed during mass production. However, due to differences in the quality of incoming microphone and speaker units, as well as variations in the cavity design during assembly, the performance of the finished products may differ slightly. To compensate for these errors and ensure consistent noise cancellation, the noise cancellation gain values need to be fine-tuned during mass production, and the noise cancellation effect must be tested and programmed online. The traditional approach is to manually adjust the gain, manually verify it until the desired noise cancellation effect is achieved, and then manually program the headphones.
This traditional manual method will face a series of problems once it reaches the mass production stage:
- The adjustment process is inefficient. Even skilled personnel typically need at least 1-2 minutes to manually adjust the process, resulting in a significant waste of production capacity.
- Low adjustment precision. Due to manual adjustment, it is impossible to accurately adjust to the set noise reduction level, resulting in low product consistency and affecting the product’s core competitiveness.
- The failure rate is high. Taking AMS chips as an example, they cannot be programmed again after three attempts. Manual adjustments cannot guarantee 100% success after three attempts, leading to a higher defect rate and wasting human and financial resources.
- The testing requirements for hybrid noise cancellation products cannot be met. Hybrid noise cancellation using both FF and FB microphone will require co-tuning of four registers, which cannot be adjusted manually.
The MegaSig AudioExpert-based ANC headphone testing platform supports almost all noise cancellation solutions on the market (including but not limited to: QCC, BES, Airoha, Realtek, Bluetrum, Actions, JL, WUQI, Beken, GearRadio, AMS, Audiowise, Synaptics, SmartLink, ATS, and other SoC solutions), enabling stable automated testing and programming on finished product lines. MegaSig has partnered with leading ODMs and noise cancellation solution manufacturers, and this system has achieved great success in both R&D and production lines, reliably and effectively creating value for customers.
This system also supports the measurement of key electroacoustic parameters of components such as headphones and microphones when ANC is disabled, allowing customers to complete their measurement needs in one stop. The software parameters are easy to configure, and the testing process is fast and accurate, maximizing production efficiency and ensuring product quality. It provides manufacturers with cost reduction and efficiency gains, earns the trust of brand manufacturers, and ultimately expands the market, achieving a win-win-win situation.
The ANC wireless calibration system test items include: speaker frequency response/distortion, ANC passive noise reduction, FB single-mic feedforward noise reduction, FF single-mic feedforward noise reduction, hybrid noise reduction, etc.
MegaSig ANC Headphone Testing System Layout
System Configuration
- AudioExpert Basic Analysis Software
- Analysis software AudioExpert ANC Function
- PM6143 analyzer, 1 unit
- Bluetooth Adapter U982, 1 unit
- AH215, a dedicated jig for in-ear headphones, 1 unit
- Pressure field microphone kit CM311+A804, 2 sets
- SB05, 1 unit, mid-low frequency audio source
- Computer host, 1 unit
- Display, 1 unit
- Silent enclosure AB03, 1 unit
- Work cabinet D03, 1 unit
- Customized fixture, 1 unit
- Customized test sequence, 1 unit