Theoretical and experimental investigation of sound power transmitting through reflecting plane with low surface density in the calibration of reference sound sources

The study investigates sound power transmitting through the wooden board floor quantitatively. The authors designed the hemispherical frame to realize a measurement surface with the radius of 2.0m. The reference sound source (RSS) is set on the floor at the center of the frame. Twenty WS2F microphones are fixed to the frame using microphone holders and connected to preamplifiers. The output voltage of each microphone is acquired simultaneously by a 20 ch FFT analyzer. A PC automatically controls the FFT analyzer and calculates the sound power level. At frequencies over 1 kHz, the transmitting sound power is negligible for the surface density of the wooden board floor in our calibration system. From 125 Hz to 1 kHz, showed that experimental results are in good agreement with theoretical values and that the transmitting sound power does increase as the surface density of the floor decreases. This means that the transmitting sound power can be theoretically estimated and that the sound power measured in our system can be corrected for precise sound power calibration.