Interference suppression and measurement method in reverberation time experiments

In response to the large standard error problems encountered in the measurement experiment on the course of “Acoustic Engineering and Application Experiments”, a reform research exploration was conducted on the reverberation time experiment. Firstly, the loudspeaker in the corner of the reverberation chamber was changed from being placed the to being supported by elastic springs. Secondly, the microphone and its preamplifier were suspended by elastic springs to reduce vibrations. The elastic springs supporting and suspending the equipment can eliminate power frequency interference with the loudspeaker. Thirdly, multiple hemispherical scatterers were installed on the inner walls of the reverberation chamber to improve sound field uniformity. Finally, a single-frequency continue wave (CW) pulse was transmitted by the generator to excite the reverberation chamber. The reverberation time was calculated using the reverse integration method, and the previous measurement method of cutting off single-frequency sine signal was abandoned. By analyzing the measured data of the same reverberation chamber, the standard error of the reverberation time at different frequencies was reduced from a maximum of 129 ms to no more than 31 ms. The results show that the aforementioned measures have achieved the goal of interference suppression during the experimental process and enhanced the measurement accuracy of the reverberation time.