Acoustic Laboratory Thailand (ALT) uses a Moving Microphone to test Airborne Sound Insulation (STC, Rw) to achieve the highest level of accuracy in acoustic testing.
Measuring the Sound Transmission Class (STC) is a crucial process for evaluating the sound insulation performance of materials and structures according to ASTM E90 and ISO 10140-2 standards. Typically, STC measurements are conducted using a measurement microphone that is fixed in a stationary position. However, in some cases, the Moving Microphone technique can enhance accuracy and effectively reduce measurement deviations.
What is Moving Microphone?
A Moving Microphone is a technique where the microphone moves during sound measurement to reduce the effects of sound wave interference (standing waves) and to achieve a more consistent average sound level. Typically, the movement of the microphone follows these patterns:
• Linear Motion – Moves in a straight line within the receiving room.
• Circular Motion – Rotates in a circular path to collect data from multiple directions.
• Random Motion – Moves randomly to reduce point-specific sound reflections.
Advantages of Using a Moving Microphone in STC Measurement
✅ Reduces the Impact of Standing Waves – Minimizes errors caused by standing waves that can distort measurements.
✅ Increases Accuracy of Average Sound Levels – Improves the accuracy and consistency of sound insulation calculations.
✅ Complies with International Testing Standards – Many standards, such as ASTM and ISO, allow the use of the Moving Microphone technique to enhance measurement results.
Ensure the highest quality standards with us! Customers using our services will be taken care of with top-level standards, along with a pre-test to check for sound leakage and installation flaws using an Acoustic Camera for even more accurate results!