Final answer:
The auditorium panels use the property of reflection to direct sound waves, changing their direction without altering amplitude, frequency, or velocity.
Step-by-step explanation:
An auditorium with special panels installed along its walls and portions of the ceiling is utilizing the wave property of reflection. Reflection occurs when a wave bounces off a barrier and changes its direction. This effect allows sound waves to be directed towards the audience, enhancing the acoustics of the auditorium. According to our references, reflection is not a change in amplitude, frequency, or velocity, but specifically the change in direction of a wave when it encounters a barrier. With sound waves, different wavelengths will reflect differently, which is why these panels are designed to reflect a range of frequencies for optimal audio quality.
Diffraction is another wave property, where a wave bends around the edges of an opening or an obstacle. However, this phenomenon is not primarily harnessed by the acoustic panels in an auditorium. Instead, diffraction can be observed when sound waves spread out after passing through a doorway, demonstrating that sound waves can bend into parts of the room not directly in the line of the doorway, due to their wavelengths being on the order of the size of the door.