| Japanese | English |
This time, a helicopter noise is measured at the Air Self Defense Force Komaki base.
|Date||27 Feb. 2002 13:00|
|Temperature||18 degrees centigrade|
|WAVE file:||air5.wav (44.1kHz / Stereo / 8sec / 1.34MB)|
Background noise level was 48-50 dB.
A helicopter appeared at the place where we are measuring the
takeoff noise of a fighter. Although it is heard quite noisy, they are about
53 dBA according to the sound level meter.
The helicopter passes from left to right. It is far from us.
Sound becomes large and small repeatedly.
The 1/3 octave analysis and the peak level display of the helicopter sound is
The time-frequency display of power spectrum.
The real time display of the ACF. Actually, the amplitude becomes large or
Running ACF measurement with the integration time of 0.2 seconds was performed
for 8 seconds.
Analysis by SA (Sound Analyzer). This is the time course of the relative
sound pressure level.
By the screen copy function, graphs of the calculation result can be captured.
January 2002 by M.Sakurai