1. The problem statement, all variables and given/known data Two in-phase loudspeakers are 2.55 m apart. They emit sound with a frequency of 370.0 Hz. A microphone is placed half-way between the speakers and then moved along the line joining the two speakers until the first point of constructive interference is found. At what distance from that midpoint is that first point? The speed of sound in air is 340 m/s 2. Relevant equations λ = v/f 3. The attempt at a solution Ok, so first thing is to find the wavelength, v/f = 340/370 = 0.919m What is wanted is constructive interference, so the path difference/λ should be a whole number, and the first point of constructive interference would be when path difference/λ = 1. Now the midpoint between the two speakers is 2.55/2 = 1.275m. Not really sure how to put it all together.