The Weighted Sound Insulation Level refers to the sound insulation level measured through a weighting network. Under the condition that the frequency spectrum and sound level of the sound source room are fixed, the sound insulation level measured in the receiving room is used to evaluate the sound insulation of walls or components.

The weighted sound insulation level is determined by comparing a standard curve with the sound insulation frequency characteristic curve of the component. The standard curve takes into account the auditory characteristics of the human ear, meaning that the ear is less sensitive to high-frequency sounds compared to low-frequency sounds. Additionally, it considers that the sound insulation of components is generally lower at low frequencies and higher at high frequencies. The standard curve is a broken line that varies with frequency. Although the sound insulation levels at different frequencies are different, the perceived sound insulation effect is the same, similar to the equal-loudness contour. In fact, it represents an equal sound insulation effect curve.

      The steps for determining the weighted sound insulation level are as follows:

Firstly, plot the sound insulation levels of the soundproof components across different frequencies on a graph with the insulation level on the vertical axis and frequency on the horizontal axis, and connect them to form a sound insulation frequency characteristic curve. Then, draw the standard curves for evaluating weighted sound insulation levels on a transparent sheet with the same coordinate scales (or copy the standard curves onto transparent polyester film). Place the transparent standard curve graph above the sound insulation frequency characteristic curve graph, align the frequency coordinates of both graphs, and move them vertically up and down until they meet the following two conditions.

    The 1/3 octave sound insulation frequency characteristic curve should meet the following requirements:

The total sum of dBs below the standard curve for all bands does not exceed 32dB.

(2) The sound insulation level of any frequency band in the sound insulation frequency characteristic curve should not exceed an adverse deviation of more than 8 dB below the standard curve.

       The frequency characteristics curve for 1/1 octave band isolation should meet the following requirements:

(1) The total sum of dBs under the standard curve for all bands does not exceed 10 dB.

(2) The sound insulation level of any frequency band in the sound insulation frequency characteristic curve should not exceed a negative deviation of more than 5 dB below the standard curve.

Next, draw a vertical line upwards from 500Hz and intersect it with the standard curve. Draw a horizontal line from the intersection point to the vertical axis of the sound insulation frequency characteristic curve. The dB value at the intersection point is the required weighted sound insulation level, RW.