Which phenomenon explains a perceived pitch change due to motion of the source or listener?

Which phenomenon explains a perceived pitch change due to motion of the source or listener?

• A. Reflection
• B. Doppler effect
• C. Diffraction
• D. Closure

Answer: (B)

The Doppler effect explains how motion between a sound source and the listener changes the pitch you perceive. When the source moves toward you, the sound waves are compressed, so the frequency reaching your ears goes up and the pitch sounds higher. When the source moves away, the waves are stretched out, the frequency drops, and the pitch sounds lower. The same idea applies if you’re moving toward or away from a stationary source. This phenomenon is why sirens or train horns seem higher as they approach and lower as they pass by. Other concepts like reflection (echo), diffraction (baving around obstacles), or perceptual filling-in don’t account for systematic pitch changes tied to motion, so they don’t explain the effect as directly as the Doppler effect does.

The Doppler effect explains how motion between a sound source and the listener changes the pitch you perceive. When the source moves toward you, the sound waves are compressed, so the frequency reaching your ears goes up and the pitch sounds higher. When the source moves away, the waves are stretched out, the frequency drops, and the pitch sounds lower. The same idea applies if you’re moving toward or away from a stationary source. This phenomenon is why sirens or train horns seem higher as they approach and lower as they pass by. Other concepts like reflection (echo), diffraction (baving around obstacles), or perceptual filling-in don’t account for systematic pitch changes tied to motion, so they don’t explain the effect as directly as the Doppler effect does.