室内声场简正波法的数值计算方法和混响场中声强测量的误差

简正波法是求解室内声场的一种较准确的数值计算方法,准确度由所取级数的项数而定,本文详细讨论了数值计算方法、级数的收敛性,并以图线来表明在声源点级数的发散及在声源附近计算的困难,本文还讨论声强测量的理论误差,用一般声强计在混响场中测量声强,误差是很大的,以致所得结果完全不可信任,如将传声器易位、前后两次测得的声强取平均,测量误差就可大大减小,若能采用精密仪器,使两个通道的相位差小于0.05°,则测量结果的统计误差可控制在合理范围内。

Computation of sound field in a reverberation room with simple harmonic wave method and the theoretical error of sound intensity measurement

Simple harmonic wave method is a precise digital computation method for room acoustics.Accuracy is dependent on the number of series terms taken in computation.In this paper we havediscussed the digital coluputation method and series convergence speed and domaim,and shown thedivergence at the sound source position and the difficulty to performing computation at the proximityof the sound source by diagrams.We have also discussed the theoretical errors of sound intensitymeasurement in reverberation sound field.The measurement errors are so great that the measurement isnonsense if one uses an ordinary sotund intensity meter.To average two measurement sound intensitiesat a sound field position by reversing the probe direction can reduce measurement error a great lot.If we can get a precise sound intensity meter with phase diference between two channels within 0.05 degree,the measurement error can be controlled in a reasonable range.