Chapter 35, Problem 4PQ

You are seated on a couch equidistant between two speakers. The speakers are 2.0 m apart and you are seated 4.0 m away from the point between the speakers as shown in Figure P35.4. Both speakers play an A note (a constant frequency of 440 Hz) in phase and at the same volume. As you move left and right along the couch, you notice that the volume alternates between minimum and maximum due to interference effects. Assume the speed of sound is 343 m/s.

1. a. When you are seated at the center of the couch, is the sound a maximum or minimum in volume?
2. b. If you slide along the couch to the left or right, approximately how far do you need to move until you reach the next location that has the same volume? (Hint: You may wish to obtain an exact expression and then use a spreadsheet or trial and error to find an approximate solution.)

FIGURE P35.4