As the source of sound moves towards the observer, the frequency of the sound waves will increase, causing the pitch of the sound to appear higher. Conversely, as the source moves away from the observer, the frequency will decrease, causing the pitch of the sound to appear lower. The amplitude of the sound may also change, becoming louder as the source approaches and softer as it moves away. Additionally, the speed at which the sound waves reach the observer may change, affecting the timbre or quality of the sound.
