Pitch
Pitch is a fundamental aspect of sound that relates to how high or low a note is perceived. It is closely tied to the frequency of sound waves, which is measured in hertz (Hz) and refers to the number of vibrations per second. While frequency is an objective measure, pitch is subjective and influenced by individual perception. Sounds can be categorized into definite and indefinite pitches; definite pitches are sounds that can be clearly identified and measured, while indefinite pitches are more ambiguous and challenging to discern, such as those produced by certain percussion instruments.
In musical terms, pitch is organized into scales, with intervals like octaves representing specific frequency ratios, notably a 2:1 ratio. Additional factors such as loudness and timbre also affect how pitch is perceived. For example, increasing the loudness of a low pitch may make it seem even lower, while increasing a high pitch may elevate its perceived height. Understanding pitch involves recognizing its relationship with frequency and how it influences musical harmony, where multiple pitches can combine to create pleasing sounds.
Pitch
FIELDS OF STUDY: Acoustics
ABSTRACT: This article describes pitch as it relates to sound, musical tones, and frequency. Frequency and pitch are related but are not the same. Frequency is an absolute value, while pitch is more subjective and may depend on other tone qualities.
Principal Terms
- definite pitch: a sound in which the pitch is easily detected.
- frequency: the number of times a repeated event happens over time.
- harmony: the combination of two or more different musical notes played simultaneously that create a pleasant sound.
- indefinite pitch: a sound in which the pitch is not easily detected.
- loudness: a quality of sound related to amplitude.
- scale: in music, a group of notes arranged by pitch or frequency.
- timbre: the quality of a tone or sound that is unique from its loudness and pitch and allows one to distinguish between different sound sources.
- tone: a vocal or musical sound with a specific pitch and loudness.
Pitch, Loudness, and Quality
Pitch is the quality of sound related to its perceived highness or lowness. Pitch is associated with frequency but is not the same. Low pitches are associated with low frequencies, and high pitches with high frequencies. However, frequency refers to an absolute value, while pitch is subjective, depending on sound perception. The frequency of a sound wave is determined and quantified by its number of vibrations in a period of time and is measured in hertz (Hz).
Pitch relationships are perceived according to fixed ratios. Musical tones can be ascribed to relative positions on a musical scale based on frequency. The interval between the first and last notes on a scale is referred to as an "octave." When two frequencies have a 2:1 ratio, they sound as though they are an octave apart. In other words, when a frequency is halved or doubled, one hears a different octave. When listening to harmony, one usually hears a single pitch related to the lowest frequency, although some listeners can distinguish separate pitches.
Pitch also depends on other sound attributes such as loudness and timbre. If the loudness of a low pitch increases, it will be perceived as becoming lower. If the loudness of a high pitch increases, it will be perceived as becoming higher. Timbre, or tone color, allows a person to distinguish one musical sound from another of identical pitch and loudness.
Definite and Indefinite Pitch
A listener can easily identify a particular pitch when a sound or note is of definite pitch. A definite pitch has a sound that is steady with a frequency that is measurable. Indefinite pitches are nearly impossible for a listener to discern as a certain pitch. Percussion instruments such as snare drums are indefinite pitch instruments because they produce sounds lacking notes with clear pitches.
Pitch and Frequency
Pitch and frequency describe the same phenomenon but are not interchangeable. Pitch depends on the listener’s interpretation of a sound’s frequency. A real-world example relating to both pitch and frequency is band-pass filters. Band-pass filters are used in wireless transmitters and receivers and allow certain frequency ranges to pass while rejecting others and maintaining quality.
Bibliography
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Halliday, David. Fundamentals of Physics. 10th ed. Hoboken: Wiley, 2014. Print.
Nave, Carl R. "Pitch." HyperPhysics. Dept. of Physics and Astronomy, Georgia State U, 2012. Web. 3 June 2015.
"Pitch and Frequency." Physics Classroom. Physics Classroom, 1996–2015. Web. 3 June 2015.
Spilsbury, Louise, and Richard Spilsbury. Why Can’t I Hear That? Pitch and Frequency. Chicago: Heinemann, 2014. Print.
Walker, James S. Physics. 5th ed. San Francisco: Pearson, 2010. Print.