The term 'Racetrack Sound' is composed of two words, 'Vroom' and 'CLOP'. Vroom is a sound made by a motor vehicle, usually an automobile, when it accelerates. It is also the sound made by a race car as it speeds around a racetrack. CLOP is the sound made by a horse's hooves as it gallops or trots. This sound is often heard at a racetrack as horses race around the track. Together, these two sounds create the unique sound of a racetrack.