Sonocat Multifunctional Acoustic Measurement: Analysis of Transmission Paths Between Concert Hall Rooms

SonoCatPlaced in front of the sound radiation surface. Due to time constraints, we conducted "point" measurements and occasional "scan" measurements, completing a total of 62 measurements. In this measurement session, we determined the sound intensity of the radiation and calculated the normal "active" intensity. Active intensity refers to the net intensity, which is the radiation intensity minus the intensity reflected back from the room. For a radiation surface, if this value is positive, it indicates that there is net sound being radiated; if this value is negative, it indicates that there is net energy flowing into the surface (i.e., absorption), and the sound flowing out of the room through that surface is greater than that flowing in. The same surface may radiate sound at one frequency (band) while absorbing sound at another frequency (band).

Figure 1 shows the wooden "sliding door" in front of the window of Room 1 where we conducted measurements.

Figure 1: Measurement point m2

Figure 2: Active noise intensity at measurement point m2 (C-weighted)

Figure 3: "Emission" noise intensity at measurement point m2 (C-weighted)

 This measurement result shows that at 31 Hz and 80 Hz in the 1/3 octave band, there is net sound entering the room through these wooden grille doors. In other 1/3 octave bands, there is net sound penetration. The radiation intensity is significantly higher than the net result, and at low frequencies, the radiation intensity is higher than at high frequencies.

Measurement

Table 1: 23 out of 62 measurements completed in Room 1, grouped alphabetically

In the following charts, all measurements are grouped according to the letters in Table 1.

• m-Measurement: Podium

• n-Measurement: First Floor

• o-Measurement: Second Floor

Figure 4: Cross-section of the concert hall

m-Measurement

Figure 5: Active sound intensity of m- measurement (C-weighted)

Figure 6: "Emission" sound intensity of m- measurement (C-weighted)

 From the figures, it can be concluded that at low frequencies, most of the noise enters the room through measurement points 7 and 8 when the wooden sliding door is open.

n-Measurement

Figure 7: Active sound intensity of n- measurement (C-weighted)

Figure 8: "Emission" sound intensity of n- measurement (C-weighted)

From these two figures, it can be concluded that the vast majority of sound intensity is negative, indicating that sound is absorbed here.

o-Measurement

Figure 9: Active sound intensity of o- measurement (C-weighted)

Figure 10: "Emission" sound intensity of o- measurement (C-weighted)

In these measurements, o1, o3, o4, and o7 may be the locations where sound enters the room. On other surfaces, sound is absorbed.