The shotgun, like the airgun, releases all of its acoustic energy in a single pulse with a very high sound-pressure level, but with a very short duration.
In contrast, marine vibrators have a very low sound-pressure level, but it runs for a relatively long time.
In the neighborhood closest to the power plant, the A-weighted sound-pressure level
at night during the pumping operation was documented as > 50 dB(A).
We converted individual measurements of sound-pressure level
to power levels (W) before performing statistical analyses because intensity (dB) is measured on a logarithmic scale.
Results indicate that mean reaction time on a morning psychomotor vigilance task slowed significantly by 3.6 ms after exposure to recorded traffic noise during sleep, and the slowing of reaction times was directly and significantly related to increases in both the frequency and sound-pressure level
of the nightly noise events.
That means that 84db, the point at which we try to limit your daily exposure, is a sound-pressure level
about 251 million times higher than the best hearing capability, which, over time, permanently will damage your ears.
When the values of sound-pressure level
are compared separately in the height of one and two meters (Figs.
An increase of three dB suggests that the sound-pressure level
has doubled, and this is about the smallest change in sound that we can hear.
The sound-pressure level
(SPL) was approximately 75 dB for pass one and 85 dB for a second pass, at which level the crossoverless 6-inchers were moving visibly.
A contour plot of the sound-pressure level
at 500 Hz is presented on page 84.
Subjective sleepiness was assessed using the ESS, and snoring intensity was assessed using the highest one percentile ambient sound-pressure level
attained while asleep during PSG.