How to evaluate the effectiveness of sound insulation materials?

Sound insulation materials are building materials specifically designed for noise reduction, lowering the volume of sounds. But how do we evaluate the effectiveness of sound insulation materials? How can we tell if a sound insulation material is effective or not? Today, we'll introduce methods for evaluating the sound insulation effect of sound insulation materials to help you avoid common pitfalls.

Laboratory testing methods

Reverberation chamber method:

This is a commonly used testing method. In the laboratory, there are specialized reverberation chambers and anechoic chambers. A floor slab specimen with sound insulation material is placed at the opening between the reverberation chamber and the anechoic chamber to simulate the actual sound propagation environment. A stable, full-frequency noise (including low, mid, and high frequencies) is emitted in the reverberation chamber, and the sound insulation is calculated by measuring the sound intensity received on one side of the anechoic chamber.

For example, this method can accurately measure the contribution of sound insulation materials to the sound insulation effect of floor slabs at different frequencies (such as 125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, etc.). The formula for calculating the sound insulation volume is \(R = L_1 - L_2\), where \(R\) is the sound insulation volume, \(L_1\) is the sound pressure level of the sound emitted from the reverberation chamber, and \(L_2\) is the sound pressure level of the sound received from the anechoic chamber. This method provides detailed sound insulation performance data for sound insulation materials at various frequencies, offering an accurate basis for evaluating their sound insulation effect on floor slabs.

Standing wave tube method:

It is mainly used to measure the vertical incident sound absorption coefficient of materials. For the application of sound insulation materials in floor slabs, the sound absorption coefficient is an important indicator for evaluating their performance. A sample of the sound insulation material is installed at one end of a standing wave tube, and then a plane wave is emitted at the other end of the tube. By measuring the maximum and minimum sound pressure levels of the standing wave inside the tube, the sound absorption coefficient of the material can be calculated.

For example, fibrous sound insulation materials may have a higher sound absorption coefficient in the mid-to-high frequency range. This method can quickly obtain the sound absorption performance of materials with a small sample size, which is helpful for the initial screening and comparison of different sound insulation materials. However, the standing wave tube method is mainly for vertically incident sound, which is different from the multi-angle incident sound in the actual environment, but it can still be used as a reference indicator to evaluate the performance of sound insulation materials.

Field testing methods

Field measurement:

In actual buildings, professional acoustic measurement instruments (such as sound level meters) are used to measure the sound conditions in the rooms above and below the floor slab. A stable noise source is created in the room above the floor slab, such as playing pink noise (a type of noise with relatively uniform energy distribution across all frequency bands) using a loudspeaker. Then, the received sound intensity is measured at different locations in the room below the floor slab (such as the center of the room, corners, etc.).

For example, in residential buildings, this method can be used to evaluate the sound insulation effect of floor slabs after the installation of sound insulation materials in a real-world environment. Simultaneously, the type of noise source can be changed (such as simulating footsteps or voices) to observe the sound insulation effect under different types of sound. Through multiple measurements and comparisons, relatively realistic data on the effectiveness of floor slab sound insulation materials can be obtained.

Comparative Test:

For comparison, two adjacent rooms with similar structures were selected, but one of their floors had sound insulation material installed. A room without sound insulation material was used as a reference. By creating the same noise source in each room, the sound intensity received by both rooms on the opposite side of the floor was measured.

For example, in a hotel room, the floor of one room is soundproofed while the floor of the other is left untreated. The same TV program or music at the same volume is played simultaneously in both rooms, and the sound intensity is measured in the corresponding room downstairs. This comparison provides a clear visual indication of the improvement in sound insulation achieved by the soundproofing material.

The above are the methods for measuring the sound insulation effect of sound insulation materials. You can choose the appropriate measurement method according to your actual situation to make a scientific and reasonable judgment on the sound insulation effect.