Sound impulse meter

Impulse Meter Sound level meters do not respond quickly enough for measurement of impulse sounds. Impulse meters provide this quick response. They give readings in decibels for peak levels of transient sound. 

Impulse noise Noise comprising rapid increases (of at least 5 to 10dB) of short duration in the sound level. The impulse sound level Lj can be measured with appropriate equipment. If an ordinary sound level meter (not an impulse sound level meter) is used for determining the equivalent continuous level L, the measured value should be increased by 6dB. 

The units for the values in Table 5.11 are shown as dB A impulse for A, dB F impulse for flat, and dB L impulse for linear. One must pay attention when using a super low frequency sound meter to the linear reading. The linear range of its dynamic response is l-90Hz when the frequency component is over 90Hz, it becomes a low level frequency. 

The following typical combustion velocities have been observed the turbulent deflagration mode with a velocity of some dozens of meters per second in lean mixtures the sound deflagration mode, high-speed deflagration with 800-1,000 m/ s velocities, when the combustion front moves with the local sound speed relative to the reaction products the quasi-detonation mode when the velocity spectra exceeds 1,100 m/s, but is 200-500 m/s less than the CJ detonation velocity. The quasi-detonation mode velocity deficit, in comparison with thermodynamic defined values, is explained by impulse losses due to interactions with walls and obstacles. 

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