The Doppler effect is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The Doppler effect is named after the physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession.
The fundamental frequency, often referred to simply as the fundamental, is defined as the lowest frequency of a periodic waveform. In music, the fundamental is the musical pitch of a note that is perceived as the lowest partial present. In terms of a superposition of sinusoids, the fundamental frequency is the lowest frequency sinusoidal in the sum of harmonically related frequencies, or the frequency of the difference between adjacent frequencies. In some contexts, the fundamental is usually abbreviated as f0, indicating the lowest frequency counting from zero. In other contexts, it is more common to abbreviate it as f1, the first harmonic.
A pan flute is a musical instrument based on the principle of the closed tube, consisting of multiple pipes of gradually increasing length. Multiple varieties of pan flutes have been popular as folk instruments. The pipes are typically made from bamboo, giant cane, or local reeds. Other materials include wood, plastic, metal and ivory.
An idiophone is any musical instrument that creates sound primarily by the vibration of the instrument itself, without the use of air flow, strings (chordophones), membranes (membranophones) or electricity (electrophones). It is the first of the four main divisions in the original Hornbostel–Sachs system of musical instrument classification. The early classification of Victor-Charles Mahillon called this group of instruments autophones. The most common are struck idiophones, or concussion idiophones, which are made to vibrate by being struck, either directly with a stick or hand or indirectly, with scraping or shaking motions. Various types of bells fall into both categories. A common plucked idiophone is the Jew's harp.
Overblowing is the manipulation of supplied air through a wind instrument that causes the sounded pitch to jump to a higher one without a fingering change or the operation of a slide. Overblowing may involve a change in the air pressure, in the point at which the air is directed, or in the resonance characteristics of the chamber formed by the mouth and throat of the player.
Wind chimes are a type of percussion instrument constructed from suspended tubes, rods, bells or other objects that are often made of metal or wood. The tubes or rods are suspended along with some type of weight or surface which the tubes or rods can strike when they or another wind-catching surface are blown by the natural movement of air outside. They are usually hung outside of a building or residence as a visual and aural garden ornament. Since the percussion instruments are struck according to the random effects of the wind blowing the chimes, wind chimes have been considered an example of chance-based music. The tubes or rods may sound either indistinct pitches, or fairly distinct pitches. Wind chimes that sound fairly distinct pitches can, through the chance movement of air, create simple songs or broken chords.
A key is a component of a musical instrument, the purpose and function of which depends on the instrument. However, the term is most often used in the context of keyboard instruments, in which case it refers to the exterior part of the instrument that the player physically interacts in the process of sound production.
A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator can be either electromagnetic or mechanical. Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal. Musical instruments use acoustic resonators that produce sound waves of specific tones. Another example is quartz crystals used in electronic devices such as radio transmitters and quartz watches to produce oscillations of very precise frequency.
Corrugated galvanised iron or steel, colloquially corrugated iron, wriggly tin, pailing, corrugated sheet metal, zinc or custom orb / corro sheet (Australia) and occasionally abbreviated CGI is a building material composed of sheets of hot-dip galvanised mild steel, cold-rolled to produce a linear ridged pattern in them. Although it is still popularly called "iron" in the UK, the material used is actually steel, and only the surviving vintage sheets may actually be made up of 100% iron. The corrugations increase the bending strength of the sheet in the direction perpendicular to the corrugations, but not parallel to them, because the steel must be stretched to bend perpendicular to the corrugations. Normally each sheet is manufactured longer in its strong direction.
Musical acoustics or music acoustics is a multidisciplinary field that combines knowledge from physics, psychophysics, organology, physiology, music theory, ethnomusicology, signal processing and instrument building, among other disciplines. As a branch of acoustics, it is concerned with researching and describing the physics of music – how sounds are employed to make music. Examples of areas of study are the function of musical instruments, the human voice, computer analysis of melody, and in the clinical use of music in music therapy.
A flue pipe is an organ pipe that produces sound through the vibration of air molecules, in the same manner as a recorder or a whistle. Air under pressure is driven through a flue and against a sharp lip called a labium, causing the column of air in the pipe to resonate at a frequency determined by the pipe length. Thus, there are no moving parts in a flue pipe. This is in contrast to reed pipes, whose sound is driven by beating reeds, as in a clarinet. Flue pipes are common components of pipe organs.
A steam whistle is a device used to produce sound in the form of a whistle using live steam, which creates, projects, and amplifies its sound by acting as a vibrating system.
Helmholtz resonance or wind throb is the phenomenon of air resonance in a cavity, such as when one blows across the top of an empty bottle. The name comes from a device created in the 1850s by Hermann von Helmholtz, the Helmholtz resonator, which he used to identify the various frequencies or musical pitches present in music and other complex sounds.
Acoustic resonance is a phenomenon in which an acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration.
In music, the bore of a wind instrument is its interior chamber. This defines a flow path through which air travels, which is set into vibration to produce sounds. The shape of the bore has a strong influence on the instrument's timbre.
Violin acoustics is an area of study within musical acoustics concerned with how the sound of a violin is created as the result of interactions between its many parts. These acoustic qualities are similar to those of other members of the violin family, such as the viola.
The Savart wheel is an acoustical device named after the French physicist Félix Savart (1791–1841), which was originally conceived and developed by the English scientist Robert Hooke (1635–1703).
In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the reception of such waves and their perception by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in). Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges.
A wind instrument is a musical instrument that contains some type of resonator in which a column of air is set into vibration by the player blowing into a mouthpiece set at or near the end of the resonator. The pitch of the vibration is determined by the length of the tube and by manual modifications of the effective length of the vibrating column of air. In the case of some wind instruments, sound is produced by blowing through a reed; others require buzzing into a metal mouthpiece, while yet others require the player to blow into a hole at an edge, which splits the air column and creates the sound.
A whistle is a device that makes sound from air blown from one end forced through a small opening at the opposite end. They are shaped in a way that allows air to oscillate inside of a chamber in an unstable way. The physical theory of the sound-making process is an example of the application of fluid dynamics or hydrodynamics and aerodynamics. The principles relevant to whistle operation also have applications in other areas, such as fluid flow measurement.
