If you've ever seen a Jewish man with strings hanging out of his clothing, this is probably what you were seeing. There is no particular religious significance to the tallit (shawl) itself, other than the fact that it holds the tzitzit (fringes) on its corners.
Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average, or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa).
dB of sound pressure level (dB SPL) is defined as: 20 log 10 p1/p0 where p1 is actually measured sound pressure level of a given sound, and p0 is a reference value of 20Î¼Pa, which corresponds to the lowest hearing threshold of the young, healthy ear.