Inverse Square Measurement System in an Anechoic Chamber

MFAC

In an anechoic chamber, to verify the absorption characteristics (compliance with the inverse square law), measurements are conducted using a mobile microphone. Inverse square measurement is a highly labor-intensive task.

Recently, our company has been conducting measurements in accordance with ISO 26101. We stretch wires inside the anechoic chamber and manually move them incrementally using gears. Conducting inverse square measurements in one anechoic chamber can take up to two days. Therefore, we investigated how other companies perform these measurements.

According to our acoustic technology consultant, we learned about an automatic microphone system being used at Tongji University in China. It seems to have been developed by an acoustics research institute in Beijing. Although we cannot disclose details, it was an intriguing device.

However, automatic systems, compared to manual ones, offer simpler operation but require more time for setup. In inverse square measurements, various speakers are used, differing in size and shape. Consequently, wires and microphones must be set up each time to align with the center points of the speakers.

Currently, our company is developing a mobile microphone system to address these challenges. We look forward to announcing it soon.