Low-noise microphone & Sound Power Level Measurement System

A microphone is a sensor that converts sound into electrical signals to measure its loudness and pitch. Microphones have a type of noise called "self-noise," which they generate themselves. Sounds quieter than this self-noise cannot be measured accurately, but the low-noise microphone we have just released reduces the self-noise level to one of the world's best, making it possible to measure minute sounds in the 10dB range, which are difficult to measure with conventional measurement microphones. In recent times, with the demand for noise reduction measures becoming stricter due to the COVID-19 pandemic and other factors, this microphone is finding more use in industries such as air conditioning and automotive, where quiet operation is particularly important.

To the best of our knowledge, this is the microphone with the lowest self-noise level among microphones of this aperture (1/2 inch). Furthermore, by adopting the "back electret" structure, a first for low-noise microphones in Japan, it can be directly connected to analysis equipment, making it easier to use and reducing initial costs.

Yes, that's right. I'm one of the development team members, but this development project involved many tasks, so the entire microphone development team worked together as one. In order to reduce the self-noise level to below 10dB, we had to go beyond our company's previous technological limits, so we relearned the fundamentals of physical phenomena and proceeded by rebuilding everything from scratch. Another major point was that we adopted a new method, the use of simulation, at the suggestion of the team leader.

Generally, simulator tools are often used in electronic circuit design, but this time we adopted a method that models the physical phenomena of the microphone and allows for the integrated evaluation of the physical phenomena and electronic circuit on the simulator. By reducing the process of actually manufacturing and evaluating the product, and by being able to adjust parameters on the simulator, I believe this was a breakthrough in this development and led to good results. Also, because low-noise microphones are very delicate in that they can pick up even the slightest sounds, it was very difficult to establish a system for mass production with stable quality. I am very happy that we were able to reach the release stage by having close meetings and coordinating with all parties involved.

The development team achieved performance that exceeded my initial expectations. This was the first product I was truly in charge of planning, so there were many challenges as I had to learn while leading. However, the development team produced outstanding results, and I myself grew through this experience, so I'm glad I took on this challenge.

In recent years, with the increasing trend towards noise reduction across various industries, we've received many requests for solutions that can accurately measure even the quietest sounds. Our product has been particularly well-received by these customers. While it's more expensive than typical microphones, it's also cheaper than comparable products from other companies, which is another point that customers appreciate.

Acoustic power level is an index that measures the noise level by capturing the sound emitted from equipment not at a single point, but across the radiating surface. While the sound level of equipment can vary depending on the measurement location, the acoustic power level measurement method is defined by international standards. Therefore, it is a globally recognized noise level index used in various industries, including office equipment such as printers and multifunction devices, air conditioning equipment, home appliances, and automotive parts. This time, we have released a new system using our DS-5000 Sound and Vibration Analysis System which was released several years ago, and O-Solution.

The ability to save measurement results as reports and the addition of features useful for root cause analysis have made it easy to perform not only measurements but also detailed subsequent analysis and identification of sound source locations. Furthermore, in recent years, there has been an increase in products that emit high-pitched noises, such as motors, so the measurement range has been expanded to include higher frequency ranges than international standards.

This has also been well-received. We are honored that the Japan Quality Assurance Organization (JQA), a key organization in Japan's quality assurance system, has adopted our O-Solution DS-5000 Sound Power Level Measurement System using low-noise microphones. By adopting low-noise microphones, it is possible to evaluate even quieter sounds than can be measured with conventional microphones, thus contributing to the improvement of quality assurance in Japan. We are also delighted to have received positive feedback from the person in charge.

In developing this product, we not only interpreted multiple international standards and incorporated them into the software, but also visited customers to gather information on usage and requirements, aiming for a simpler and more user-friendly product. Achieving both standard compliance and user-friendliness simultaneously was challenging, but I believe that effort led to a better product. Furthermore, I and the other development team members deepened our understanding of the standards and improved our skills through this development process, which I also consider a positive outcome.

The development of this low-noise microphone was prompted by the increasing demand for quieter operation, but I believe that the products our customers need change with the times. Going forward, we want to quickly grasp our customers' evolving needs and focus our product development on addressing them.

Personally, I gained a great deal of skill in electronic circuits through this development project. I hope to fully utilize those skills in the next product development.

Since sound power levels are defined by standards, it's crucial to ensure we can properly respond to any revisions to those standards. Furthermore, we don't just want to stop at measurement; we also want to add features that help customers who want to "lower the volume," and we plan to continue updating our software in the future.