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).
The human ear is not equally sensitive to sounds (tones) of the same sound pressure levels but different frequencies. This subjective or perceived magnitude of a sound by an individual is called its loudness. The loudness of a sound is not equal with its sound pressure level and differs for different frequencies. In order to assess loudness of a sound the isophonic curves are explored.