STC – Acoustic Alliance Thailand

Testing of Sound Barriers and Standards

ISO Standards, Noise Barrier, Sound Absorption, STC / webmaster

The effectiveness of a sound barrier cannot be assessed by design or materials alone—it must be verified with internationally recognized test results. Acoustic Laboratory Thailand Co., Ltd. (ALT) offers expert sound barrier testing in a laboratory setting (Lab Test) according to the following international standards: Laboratory Test 1. Sound Transmission Loss Testing Conducted according to ISO 10140-2, EN 1793, or ASTM E90 standards Tests the Sound Transmission Loss (STL) of barriers or material panels Measures sound insulation performance across specific frequencies, such as 125 Hz to 5000 Hz or broader ranges Results can be evaluated as ratings like Rw or STC, which numerically represent the material’s sound-blocking performance ALT provides fully equipped standard testing chambers capable of performing these tests to ensure that selected materials or barriers meet required acoustic performance specifications. 2. Sound Absorption Testing Conducted in accordance with ISO 354, ISO 11654, or ASTM C423 Uses a reverberation chamber to measure the sound absorption properties of materials Results are presented as the Sound Absorption Coefficient (SAC) across various frequencies or as the NRC (Noise Reduction Coefficient), which is an average value Helps determine how effectively a material absorbs sound within the targeted frequency range These tests assist designers and developers in selecting the most suitable soundproofing materials based on real-world application requirements. Field Test For sound barriers installed in real-world environments, a key method is measuring Sound Insertion Loss (SIL) in accordance with ISO 10847, which evaluates the actual impact of the barrier on the surrounding acoustic environment. Additionally, modern technology enables in-situ sound absorption testing using the Local Plane Wave technique and Array Microphone systems. In Thailand, there are acoustic specialists capable of conducting such field tests on noise barriers, ensuring that the results accurately reflect real site conditions.

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Using a Moving Microphone in Testing STC for Material Sound Insulation

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. ASTM E90 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!