The portable sound intensity meter can directly obtain the sound intensity vector (including size and direction) by measuring the sound pressure and particle vibration velocity of sound propagating in the medium. This unique advantage makes it of great value in on-site measurement of building acoustics, especially suitable for scenarios where traditional methods cannot meet the harsh testing conditions.
1、 Sound absorption coefficient measurement: an on-site solution to replace the reverberation chamber method
The traditional measurement of sound absorption coefficient needs to be carried out in a professional reverberation room, which is difficult to use for on-site component evaluation. Portable sound intensity meters provide an alternative solution.
Measurement principle and steps:
Principle: Using the sound intensity transfer function method. Place the dual microphone probe of the sound intensity meter in front of the surface of the material to be tested, and measure the vector difference between the incident sound intensity and the reflected sound intensity. By calculating the normal sound intensity level, the sound absorption coefficient of the material can be obtained.
Steps:
Arrange one or more measurement points (or scan) in front of the material.
Use a stable sound source (such as a speaker) to emit noise.
The sound intensity meter directly measures the sound absorption coefficient without depending on the diffusion sound field conditions.
Advantages and limitations:
Advantages: No dedicated reverberation room is required, and measurements of components such as walls and ceilings can be directly taken on site, resulting in results that are closer to actual usage conditions.
Limitations: Measurement results are affected by acoustic field conditions (non diffusive fields), which may limit accuracy at extremely low frequencies. It is often used as an effective tool for engineering evaluation and comparison.
2、 Sound insulation performance evaluation: precise quantification of sound transmission loss
Traditional sound insulation measurement requires the testing room to meet the conditions of expanding the field and the background noise to be sufficiently low. The sound intensity rule breaks through these limitations.
Measurement principle and steps:
Principle: Directly measure the sound power passing through the partition wall or component. On one side of the partition wall, use a sound intensity meter to scan the entire wall and measure the total sound power transmitted to the wall; On the other side, scan and measure the total transmitted sound power. The difference between the two is the apparent sound insulation of the component.
Steps:
In the sound source chamber, scan and measure the sound power incident on the component.
In the receiving room, scan and measure the transmitted sound power of the component.
Calculate the difference between the two sound power levels to determine the sound insulation.
Core advantages:
Not affected by background noise interference: Due to the directional nature of the sound intensity meter, it can effectively suppress the influence of background noise on the receiving room side, and can accurately measure even in noisy environments.
Identifying the weak links in sound insulation: By using the sound intensity distribution cloud map, it is possible to intuitively locate sound insulation defects such as "sound bridges" and gap leaks, providing a direct basis for improving design.
Summary: Portable sound intensity meters provide a revolutionary tool for on-site acoustic measurement, making it possible to quickly and directionally evaluate sound absorption and insulation performance, particularly suitable for building quality acceptance, fault diagnosis, and existing building renovation.