Sound is created by vibrations that travel through a medium, such as air or water. These vibrations reach our ears and are interpreted by our brains. Sound possesses several characteristics, including loudness, duration, and a quality known as pitch. Understanding pitch helps us differentiate between the sounds we encounter daily.
What is Sound Pitch?
Pitch refers to how high or low a sound is perceived. It is a perceptual quality that enables us to order sounds along a scale from low to high. For instance, a tiny whistle produces a sound that we describe as high-pitched, while the deep rumble of thunder is considered low-pitched. This auditory attribute allows us to distinguish musical notes and recognize different voices. Pitch is a subjective experience.
The Science of Pitch
The perception of pitch is directly related to a sound wave’s frequency. Frequency measures the number of vibrations or cycles a sound wave completes per second. It is typically measured in Hertz (Hz), where one Hertz equals one cycle per second. A high-pitched sound corresponds to a sound wave with a high frequency. These high-frequency waves also have shorter wavelengths.
Conversely, a low-pitched sound results from a sound wave with a low frequency. Consequently, these low-frequency waves possess longer wavelengths. For example, a small instrument like a flute produces high-frequency sounds, leading to a high pitch. In contrast, larger instruments such as a tuba or a double bass generate low-frequency sound waves, which are perceived as low-pitched.
Hearing Highs and Lows
Our daily lives are filled with examples of both high and low-pitched sounds. High-pitched sounds include the chirping of a bird, the squeal of a mouse, or a child’s voice. The sharp sound of a whistle or the ringing of a school bell are also common high-pitched examples. In contrast, low-pitched sounds encompass the deep roar of a lion, the resonant tones of a large drum, or a man’s voice. The distant rumble of thunder is another low-pitched example.
The human ear is capable of detecting a wide range of frequencies, translating these physical vibrations into the sensation of pitch. For a person with normal hearing, this range typically extends from approximately 20 Hz to 20,000 Hz. While we can perceive sounds across this broad spectrum, our hearing is most sensitive to frequencies between 2,000 and 5,000 Hz. Sounds below 20 Hz are known as infrasound, and those above 20,000 Hz are called ultrasound, both generally beyond human hearing.