Two identical speakers, $5\mathrm{.}0$ meters apart, produce coherent sound waves. As you walk in a straight line from one speaker to another, you hear the loudest possible sound when you are $1\mathrm{.}5$ meters from the nearest speaker. What are the lowest and highest possible frequencies ${?}^1$ produced by the speakers? Take the speed of sound in air to be $343\frac{m}{s}.$