1. The problem statement, all variables and given/known data Imagine you are in an open field where two loudspeakers are set up and connected to the same amplifier so that they emit sound waves in phase at 688 Hz. Take the speed of sound in air to be 344 m/s. What is the shortest distance d you need to walk forward to be at a point where you cannot hear the speakers? 2. Relevant equations f1= V/2L lambda1 = 2L 3. The attempt at a solution So...this is what I did... 688 = 344/2L L = .25 lambda1 = 2L lambda = 2(.25) lambda = .5 Destructive interference occurs at a distance that is half lambda. I said that the answer was .25 meters, but according to the program that is not the correct answer. So...where is my error? (It is always possible the program is wrong, but normally it is me) Please help me identify my mistake.