Do you mean "The Doppler Effect"?
Inflection
Semitone
The up and down movement of an airplane's nose is called "pitch." Pitch refers to the angle of the aircraft's nose relative to the horizon and is controlled primarily by the elevators on the tail of the airplane. Adjusting pitch affects the aircraft's ascent or descent during flight.
Pitch of vibrating objects is determined by the frequency of their vibrations. Objects that vibrate at a higher frequency produce higher pitch sounds, while objects that vibrate at a lower frequency produce lower pitch sounds.
Ummm . . . the change of pitch is called a modulation. Perhaps that is what you are asking. Or . . . a higher-pitched harmony in singing is called a Descant.
Elevators change the pitch of the aircraft.
The change in pitch you hear as the ambulance passes by is called the Doppler effect. This phenomenon occurs because the sound waves are compressed as the ambulance approaches and stretched as it moves away, resulting in a higher pitch as it comes closer and a lower pitch as it moves away.
The apparent change in pitch of a moving sound source is called the Doppler effect. It describes how the frequency of the sound waves perceived by an observer changes as the source of the waves moves relative to the observer.
Valves. They're used to change the pitch.
As the frequency of a sound wave changes, the pitch of the sound will also change. Higher frequencies will result in higher-pitched sounds, while lower frequencies will produce lower-pitched sounds. This change in pitch is a result of the number of wave cycles per second altering the perception of the sound's frequency.
A change of pitch in a sound is caused by a change of wavelength. This can be caused by a change in length or size of the vibrating or oscillating device or system causing the sound. When you press on a guitar string at one of the frets, for instance, you shorten the vibrating part of the string thereby shortening its wavelength and increasing its pitch - shorter wavelength = higher pitch.*The pitch of a sound can also be changed by movement of the sound source away from or toward the listener. This is called Doppler effect. Moving away, the waves become stretched resulting in a lower pitch, and vice versa when moving toward the listener.*Keep in mind that all sound waves travel at the same speed, so shorter wavelengths will reach your ears in greater numbers per second than longer wavelengths. This is called frequency. Higher frequency = higher pitch and, again, vice versa.
It is called "pitch."