text: please help me? two point-source loudspeakers are a certain distance apart, and a person stands 12.0 m in front of one of them on a line perpendicular to the baseline of the speakers. if the speakers emit identical 1000.0-hz tones, what is their minimum nonzero separation so that the observer hears little or no sound? (take the speed to be exactly 340 m/s.) there must be destuctive interference.  now, wavelength = 0.34 m  path difference is sqrt(x^2+144) - 12  this must equal an integral or half number of wavelengths.  take the simplest case of phase diff. = pi  so, path difference = 0.34/2 = 0.17  so, sqrt(x^2+144) = 12.17  or x = 2.027 m