Question

The compressions ahead of a moving sound source are ________, ________ so you hear a higher pitch. Behind the moving sound source, the compressions are ________ ________, so you hear a lower pitch.

Answer 1

The compressions ahead of a moving sound source are **closer together**, **compressed**, so you hear a higher pitch. Behind the moving sound source, the compressions are **further apart**, **stretched out**, so you hear a lower pitch.