Diffraction or Distraction?? A row of seats is parallel to a stage at a distance of 8.1 m from it. At the center and front of the stage is a diffraction horn loudspeaker. This speaker sends out its sound through an opening that is like a small doorway with a width D of 0.072 m. The speaker is playing a tone that has a frequency of 2.0 104 Hz. The speed of sound is 343 m/s. What is the separation between two seats, located near the center of the row, at which the tone cannot be heard?