JBL Speaker System User Manual

SOUWind - Wind gives the illusion that a sound is coming froma different direction than it really is. This creates a re<antpropagation vector (see diag. 1). When sound propagateswith the wind it tends to refract downward, and against thewind refract upwards (see diag. 2), (*refraction is the termused to describe the bending of sound).From the speakers to our ears - Since you usually want a targetbackground SPL of about 70dB - 80dB to your listeners, keep inmind the Inverse Square Law, which states that in a free field with nowalls, floor, or ceiling, the intensity of sound decreases with thesquare of the distance. For example when you double the distancebetween the speaker and your listener's ear, the SPL decreases by6dB (i.e. If a speaker's output is 100dB SPL at 10 feet away, at 20feet away the SPL is decreased to 94dB.) Don't forget, a 1OdB dropwill sound "half as loud".ISS WlND CROSS WlNDPROPAGATION 'VECTORCROSS WlNDTemperature - Temperature differences also have a smalleffect'on sound propagation. Hot air is less dense than cold.travels faster in a less dense medium and thereforeup as air gets warmer, and slows down as air gets