抄録
The Loudness Level of S. S. Stevens, well-known as a subjective noise rating number. cannot be simply obtained because of the need of indispensable definit procedures by Octave Band Sound Pressure Level. It has already been clarified that there exists a close correlation between Sound Levels (A, B and C) and Loudness Level owing to the studies of S. Morita, A. Nakano and P. H. Parkin. But in case the Sound Level (for example, dB(A)) is used in place of the Loudness Level, it cannot be free of some error. Figs. 9, 10 and 11 show a very intimate correlation between Sound Level and Loudness Level in our investigation, using (C-A) value as a parameter on the basis of noise measured on various parts of motor cars. The results of regression analysis are given in Table 6. Furthermore, in case the formula: LL = 1/2(C+A)+10 (phon) is assumed for a simpler calculating method, the error becomes very small and no problem in operation occurs. This means that the Loudness Level can be simply measured by using only Sound Level Meter.
