| 摘要 |
PURPOSE:To execute exactly a measurement by executing a sampling from a time point which is not influenced by a direct sound, to a time point when a measured sound pressure level reaches a sound pressure level which is not influenced by a dark noise in a guide. CONSTITUTION:A timer in a computer 12 starts its operation, and when it becomes a sufficient set time by which the inside of a room 1 becomes a diffusion sound field after a loudspeaker 2 turns on, the loudspeaker 2 is turned off. At the time point of this turning-off, the time is reset, and immediately the reoperation is started. Thereafter, when an integration time of the timer becomes td1 which is not influenced by a direct sound, an input of a sampling data is started to the computer 12 from an A/D converting circuit 10. In this state, a sound pressure level in the sampling data is compared with (Lu+sigma+K) by a mean value Lu of a dark noise and a standard deviation sigma, and at the time point when both of them coincide, the input of the sampling data into the computer is ended. |
