Plucked
87-487: The bandola is one of many varieties of small pear-shape chordophones found in Venezuela and Colombia . They are related to the bandurria and mandolin . Instruments known as bandola include: Chordophone In musical instrument classification , string instruments , or chordophones , are musical instruments that produce sound from vibrating strings when a performer strums, plucks, strikes or sounds
174-547: A laser , light is amplified in a cavity resonator that is usually composed of two or more mirrors. Thus an optical cavity , also known as a resonator, is a cavity with walls that reflect electromagnetic waves (i.e. light ). This allows standing wave modes to exist with little loss. Mechanical resonators are used in electronic circuits to generate signals of a precise frequency . For example, piezoelectric resonators , commonly made from quartz , are used as frequency references. Common designs consist of electrodes attached to
261-507: A short circuit or open circuit, connected in series or parallel with a main transmission line. Planar transmission-line resonators are commonly employed for coplanar , stripline , and microstrip transmission lines. Such planar transmission-line resonators can be very compact in size and are widely used elements in microwave circuitry. In cryogenic solid-state research, superconducting transmission-line resonators contribute to solid-state spectroscopy and quantum information science. In
348-413: A "normal" plucking point, producing a canonical harpsichord sound; the other has a plucking point close to the bridge, producing a reedier "nasal" sound rich in upper harmonics. A single string at a certain tension and length only produces one note. To produce multiple notes, string instruments use one of two methods. One is to add enough strings to cover the required range of different notes (e.g., as with
435-550: A cave painting in the Trois Frères cave in France depicts what some believe is a musical bow , a hunting bow used as a single-stringed musical instrument. From the musical bow, families of stringed instruments developed; since each string played a single note, adding strings added new notes, creating bow harps , harps and lyres . In turn, this led to being able to play dyads and chords . Another innovation occurred when
522-431: A challenge to instrument builders, as compared with instruments that are only plucked (e.g., guitar), because on bowed instruments, the musician must be able to play one string at a time if they wish. As such, a bowed instrument must have a curved bridge that makes the "outer" strings lower in height than the "inner" strings. With such a curved bridge, the player can select one string at a time to play. On guitars and lutes ,
609-411: A clock or bell. Electric string instruments, such as the electric guitar , can also be played without touching the strings by using audio feedback . When an electric guitar is plugged into a loud, powerful guitar amplifier with a loudspeaker and a high level of distortion is intentionally used, the guitar produces sustained high-pitched sounds. By changing the proximity of the guitar to the speaker,
696-573: A coil of wire, is self-resonant at a certain frequency due to the parasitic capacitance between its turns. This is often an unwanted effect that can cause parasitic oscillations in RF circuits. The self-resonance of inductors is used in a few circuits, such as the Tesla coil . A cavity resonator is a hollow closed conductor such as a metal box or a cavity within a metal block, containing electromagnetic waves (radio waves) reflecting back and forth between
783-517: A half a pear shape using three strings. Early versions of the violin and fiddle, by comparison, emerged in Europe through instruments such as the gittern , a four-stringed precursor to the guitar, and basic lutes . These instruments typically used catgut (animal intestine) and other materials, including silk, for their strings. String instrument design was refined during the Renaissance and into
870-498: A heavier metal winding produces a lower pitch than a string of equal length without a metal winding. This can be seen on a 2016-era set of gut strings for double bass. The higher-pitched G string is often made of synthetic material, or sometimes animal intestine, with no metal wrapping. To enable the low E string to produce a much lower pitch with a string of the same length, it is wrapped with many wrappings of thin metal wire. This adds to its mass without making it too stiff. The frequency
957-484: A key part of orchestras – cellos, violas, and upright basses, for example, were now standard instruments for chamber ensembles and smaller orchestras. At the same time, the 19th-century guitar became more typically associated with six-string models, rather than traditional five-string versions. Major changes to string instruments in the 20th century primarily involved innovations in electronic instrument amplification and electronic music – electric violins were available by
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#17327803399201044-421: A lowest frequency called the fundamental frequency . The above analysis assumes the medium inside the resonator is homogeneous, so the waves travel at a constant speed, and that the shape of the resonator is rectilinear. If the resonator is inhomogeneous or has a nonrectilinear shape, like a circular drumhead or a cylindrical microwave cavity , the resonant frequencies may not occur at equally spaced multiples of
1131-540: A lute-like instrument came from Mesopotamia prior to 3000 BC. A cylinder seal from c. 3100 BC or earlier (now in the possession of the British Museum) shows what is thought to be a woman playing a stick lute. From the surviving images, theorists have categorized the Mesopotamian lutes, showing that they developed into a long variety and a short. The line of long lutes may have developed into
1218-402: A particular engine speed or range of speeds. In many keyboard percussion instruments, below the centre of each note is a tube, which is an acoustic cavity resonator . The length of the tube varies according to the pitch of the note, with higher notes having shorter resonators. The tube is open at the top end and closed at the bottom end, creating a column of air that resonates when the note
1305-401: A performance. The frequency is inversely proportional to the length: A string twice as long produces a tone of half the frequency (one octave lower). Pitch can be adjusted by varying the tension of the string. A string with less tension (looser) results in a lower pitch, while a string with greater tension (tighter) results in a higher pitch. Pushing a pedal on a pedal steel guitar raises
1392-407: A piece of quartz, in the shape of a rectangular plate for high frequency applications, or in the shape of a tuning fork for low frequency applications. The high dimensional stability and low temperature coefficient of quartz helps keeps resonant frequency constant. In addition, the quartz's piezoelectric property converts the mechanical vibrations into an oscillating voltage , which is picked up by
1479-533: 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. A cavity resonator is one in which waves exist in a hollow space inside the device. In electronics and radio, microwave cavities consisting of hollow metal boxes are used in microwave transmitters, receivers and test equipment to control frequency, in place of
1566-453: A specific resistor component, or due to resistance of the inductor windings. Such resonant circuits are also called RLC circuits after the circuit symbols for the components. A distributed-parameter resonator has capacitance, inductance, and resistance that cannot be isolated into separate lumped capacitors, inductors, or resistors. An example of this, much used in filtering , is the helical resonator . An inductor consisting of
1653-415: A spring, pendulums , balance wheels , and LC tuned circuits have one resonant frequency. Systems with two degrees of freedom, such as coupled pendulums and resonant transformers can have two resonant frequencies. A crystal lattice composed of N atoms bound together can have N resonant frequencies. As the number of coupled harmonic oscillators grows, the time it takes to transfer energy from one to
1740-520: A sustained sound. Some string instruments are mainly plucked, such as the harp and the electric bass . Other examples include the sitar , rebab , banjo , mandolin , ukulele , and bouzouki . In the Hornbostel–Sachs scheme of musical instrument classification , used in organology , string instruments are called chordophones. According to Sachs , Chordophones are instruments with strings. The strings may be struck with sticks, plucked with
1827-401: A transmission line causes reflection of the transmitted signal. Two such reflectors on a transmission line evoke standing waves between them and thus act as a one-dimensional resonator, with the resonance frequencies determined by their distance and the effective dielectric constant of the transmission line. A common form is the resonant stub , a length of transmission line terminated in either
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#17327803399201914-403: A violin scale is only about 13 inches (33 cm). On the shorter scale of the violin, the left hand may easily reach a range of slightly more than two octaves without shifting position , while on the bass' longer scale, a single octave or a ninth is reachable in lower positions. In bowed instruments, the bow is normally placed perpendicularly to the string, at a point halfway between the end of
2001-421: 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 (including acoustic ). Resonators are used to either generate waves of specific frequencies or to select specific frequencies from
2088-487: Is a method of playing on instruments such as the veena , banjo , ukulele , guitar, harp, lute , mandolin , oud , and sitar , using either a finger, thumb, or quills (now plastic plectra) to pluck the strings. Instruments normally played by bowing (see below) may also be plucked, a technique referred to by the Italian term pizzicato . Bowing (Italian: arco ) is a method used in some string instruments, including
2175-461: Is equal to an integer number of wavelengths λ {\displaystyle \lambda \,} of the wave: If the velocity of a wave is c {\displaystyle c\,} , the frequency is f = c / λ {\displaystyle f=c/\lambda \,} so the resonant frequencies are: So the resonant frequencies of resonators, called normal modes , are equally spaced multiples ( harmonics ) of
2262-402: Is impractical. Instruments with a fingerboard are then played by adjusting the length of the vibrating portion of the strings. The following observations all apply to a string that is infinitely flexible (a theoretical assumption, because in practical applications, strings are not infinitely flexible) strung between two fixed supports. Real strings have finite curvature at the bridge and nut, and
2349-457: Is inversely proportional to the square root of the linear density: Given two strings of equal length and tension, the string with higher mass per unit length produces the lower pitch. The length of the string from nut to bridge on bowed or plucked instruments ultimately determines the distance between different notes on the instrument. For example, a double bass with its low range needs a scale length of around 42 inches (110 cm), whilst
2436-485: Is made by cutting a narrow slit along the length of a conducting tube. The slit has an effective capacitance and the bore of the resonator has an effective inductance. Therefore, the LGR can be modeled as an RLC circuit and has a resonant frequency that is typically between 200 MHz and 2 GHz. In the absence of radiation losses, the effective resistance of the LGR is determined by the resistivity and electromagnetic skin depth of
2523-409: Is mainly used on electric instruments because these have a pickup that amplifies only the local string vibration. It is possible on acoustic instruments as well, but less effective. For instance, a player might press on the seventh fret on a guitar and pluck it at the head side to make a tone resonate at the opposing side. On electric instruments, this technique generates multitone sounds reminiscent of
2610-465: Is one of the five main divisions of instruments in the Hornbostel–Sachs scheme of musical instrument classification . Hornbostel–Sachs divides chordophones into two main groups: instruments without a resonator as an integral part of the instrument (which have the classification number 31, also known as 'simple'); and instruments with such a resonator (which have the classification number 32, also known as 'composite'). Most western instruments fall into
2697-687: Is one of the oldest string instruments. Ancestors of the modern bowed string instruments are the rebab of the Islamic Empires, the Persian kamanche and the Byzantine lira . Other bowed instruments are the rebec , hardingfele , nyckelharpa , kokyū , erhu , igil , sarangi , morin khuur , and K'ni . The hurdy-gurdy is bowed by a wheel. Rarely, the guitar has been played with a bow (rather than plucked) for unique effects. The third common method of sound production in stringed instruments
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2784-514: Is struck. This adds depth and volume to the note. In string instruments, the body of the instrument is a resonator. The tremolo effect of a vibraphone is achieved via a mechanism that opens and shuts the resonators. String instruments such as the bluegrass banjo may also have resonators. Many five-string banjos have removable resonators, so players can use the instrument with a resonator in bluegrass style, or without it in folk music style. The term resonator , used by itself, may also refer to
2871-421: Is surrounded by a material with much lower dielectric constant, then this abrupt change in dielectric constant can cause confinement of an electromagnetic wave, which leads to a resonator that acts similarly to a cavity resonator. Transmission lines are structures that allow broadband transmission of electromagnetic waves, e.g. at radio or microwave frequencies. Abrupt change of impedance (e.g. open or short) in
2958-406: Is to strike the string. The piano and hammered dulcimer use this method of sound production. Even though the piano strikes the strings, the use of felt hammers means that the sound that is produced can nevertheless be mellow and rounded, in contrast to the sharp attack produced when a very hard hammer strikes the strings. Violin family string instrument players are occasionally instructed to strike
3045-409: The standing wave is imposed on the beam. This type of system can be used as a sensor to track changes in frequency or phase of the resonance of the fiber. One application is as a measurement device for dimensional metrology . The most familiar examples of acoustic resonators are in musical instruments . Every musical instrument has resonators. Some generate the sound directly, such as
3132-496: The Baroque music era and fiddles used in many types of folk music ). All of the bowed string instruments can also be plucked with the fingers, a technique called " pizzicato ". A wide variety of techniques are used to sound notes on the electric guitar , including plucking with the fingernails or a plectrum, strumming and even " tapping " on the fingerboard and using feedback from a loud, distorted guitar amplifier to produce
3219-506: The Baroque period (1600–1750) of musical history. Violins and guitars became more consistent in design and were roughly similar to acoustic guitars of the 2000s. The violins of the Renaissance featured intricate woodwork and stringing, while more elaborate bass instruments such as the bandora were produced alongside quill-plucked citterns , and Spanish body guitars. In the 19th century, string instruments were made more widely available through mass production, with wood string instruments
3306-423: The muffler to reduce noise, by making sound waves "cancel each other out". The "exhaust note" is an important feature for some vehicle owners, so both the original manufacturers and the after-market suppliers use the resonator to enhance the sound. In " tuned exhaust " systems designed for performance, the resonance of the exhaust pipes can also be used to remove combustion products from the combustion chamber at
3393-455: The piano , which has sets of 88 strings to enable the performer to play 88 different notes). The other is to provide a way to stop the strings along their length to shorten the part that vibrates, which is the method used in guitar and violin family instruments to produce different notes from the same string. The piano and harp represent the first method, where each note on the instrument has its own string or course of multiple strings tuned to
3480-413: The resonator guitar . The modern ten-string guitar , invented by Narciso Yepes , adds four sympathetic string resonators to the traditional classical guitar. By tuning these resonators in a very specific way (C, B♭, A♭, G♭) and making use of their strongest partials (corresponding to the octaves and fifths of the strings' fundamental tones), the bass strings of the guitar now resonate equally with any of
3567-428: The saxophone and trumpet . The development of guitar amplifiers, which contained a power amplifier and a loudspeaker in a wooden cabinet , let jazz guitarists play solos and be heard over a big band. The development of the electric guitar provided guitarists with an instrument that was built to connect to guitar amplifiers. Electric guitars have magnetic pickups , volume control knobs and an output jack. In
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3654-469: The tamburs and pandura . The line of short lutes was further developed to the east of Mesopotamia, in Bactria , Gandhara , and Northwest India, and shown in sculpture from the 2nd century BC through the 4th or 5th centuries AD. During the medieval era , instrument development varied in different regions of the world. Middle Eastern rebecs represented breakthroughs in terms of shape and strings, with
3741-406: The tuned circuits which are used at lower frequencies. Acoustic cavity resonators, in which sound is produced by air vibrating in a cavity with one opening, are known as Helmholtz resonators . A physical system can have as many resonant frequencies as it has degrees of freedom ; each degree of freedom can vibrate as a harmonic oscillator . Systems with one degree of freedom, such as a mass on
3828-688: The violin , viola , cello , and the double bass (of the violin family ), and the old viol family. The bow consists of a stick with a "ribbon" of parallel horse tail hairs stretched between its ends. The hair is coated with rosin so it can grip the string; moving the hair across a string causes a stick-slip phenomenon , making the string vibrate , and prompting the instrument to emit sound. Darker grades of rosin grip well in cool, dry climates, but may be too sticky in warmer, more humid weather. Violin and viola players generally use harder, lighter-colored rosin than players of lower-pitched instruments, who tend to favor darker, softer rosin. The ravanahatha
3915-493: The 1920s and were an important part of emerging jazz music trends in the United States. The acoustic guitar was widely used in blues and jazz , but as an acoustic instrument, it was not loud enough to be a solo instrument, so these genres mostly used it as an accompaniment rhythm section instrument. In big bands of the 1920s, the acoustic guitar played backing chords, but it was not loud enough to play solos like
4002-465: The 1960s and 1970s, such as fuzz pedals , flangers , and phasers , enabling performers to create unique new sounds during the psychedelic rock era. Breakthroughs in electric guitar and bass technologies and playing styles enabled major breakthroughs in pop and rock music in the 1960s and 1970s. The distinctive sound of the amplified electric guitar was the centerpiece of new genres of music such as blues rock and jazz-rock fusion . The sonic power of
4089-408: The 1960s, larger, more powerful guitar amplifiers were developed, called "stacks". These powerful amplifiers enabled guitarists to perform in rock bands that played in large venues such as stadiums and outdoor music festivals (e.g., Woodstock Music Festival ). Along with the development of guitar amplifiers, a large range of electronic effects units , many in small stompbox pedals, were introduced in
4176-406: The action and strings of the piano were taken out of its box, it could still be played. This is not true of the violin , because the string passes over a bridge located on the resonator box, so removing the resonator would mean the strings had no tension. Curt Sachs also broke chordophones into four basic subcategories, "zithers, lutes, lyres and harps." Dating to around c. 13,000 BC ,
4263-459: The air inside it. The vibration of the body of the instrument and the enclosed hollow or chamber make the vibration of the string more audible to the performer and audience. The body of most string instruments is hollow, in order to have better sound projection. Some, however—such as electric guitar and other instruments that rely on electronic amplification—may have a solid wood body. In musicology , string instruments are known as chordophones. It
4350-417: The attached electrodes. These crystal oscillators are used in quartz clocks and watches, to create the clock signal that runs computers, and to stabilize the output signal from radio transmitters . Mechanical resonators can also be used to induce a standing wave in other media. For example, a multiple degree of freedom system can be created by imposing a base excitation on a cantilever beam. In this case
4437-478: The bare fingers or a plectrum, bowed or (in the Aeolian harp, for instance) sounded by wind. The confusing plenitude of stringed instruments can be reduced to four fundamental type: zithers, lutes, lyres, and harps. In most string instruments, the vibrations are transmitted to the body of the instrument, which often incorporates some sort of hollow or enclosed area. The body of the instrument also vibrates, along with
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#17327803399204524-404: The beam after passing through the resonators. The first resonator causes bunching of the particles passing through it. The bunched particles travel in a field-free region where further bunching occurs, then the bunched particles enter the second resonator giving up their energy to excite it into oscillations. It is a particle accelerator that works in conjunction with a specifically tuned cavity by
4611-437: The bow harp was straightened out and a bridge used to lift the strings off the stick-neck , creating the lute. This picture of musical bow to harp bow is theory and has been contested. In 1965 Franz Jahnel wrote his criticism stating that the early ancestors of plucked instruments are not currently known. He felt that the harp bow was a long cry from the sophistication of the civilizations of western Asia in 4000 BC that took
4698-487: The bridge can be flat, because the strings are played by plucking them with the fingers, fingernails or a pick; by moving the fingers or pick to different positions, the player can play different strings. On bowed instruments, the need to play strings individually with the bow also limits the number of strings to about six or seven; with more strings, it would be impossible to select individual strings to bow. (Bowed strings can also play two bowed notes on two different strings at
4785-421: The bridge, because of its motion, is not exactly nodes of vibration. Hence the following statements about proportionality are approximations. Pitch can be adjusted by varying the length of the string. A longer string results in a lower pitch, while a shorter string results in a higher pitch. A concert harp has pedals that cause a hard object to make contact with a string to shorten its vibrating length during
4872-475: The cavity is conveniently small in size. Due to the low resistance of their conductive walls, cavity resonators have very high Q factors ; that is their bandwidth , the range of frequencies around the resonant frequency at which they will resonate, is very narrow. Thus they can act as narrow bandpass filters . Cavity resonators are widely used as the frequency determining element in microwave oscillators . Their resonant frequency can be tuned by moving one of
4959-467: The cavity's walls. When a source of radio waves at one of the cavity's resonant frequencies is applied, the oppositely-moving waves form standing waves , and the cavity stores electromagnetic energy. Since the cavity's lowest resonant frequency, the fundamental frequency, is that at which the width of the cavity is equal to a half-wavelength (λ/2), cavity resonators are only used at microwave frequencies and above, where wavelengths are short enough that
5046-439: The conductor used to make the resonator. One key advantage of the LGR is that, at its resonant frequency, its dimensions are small compared to the free-space wavelength of the electromagnetic fields. Therefore, it is possible to use LGRs to construct a compact and high-Q resonator that operates at relatively low frequencies where cavity resonators would be impractically large. If a piece of material with large dielectric constant
5133-412: The configuration of the structures. The reflex klystron is a klystron utilizing only a single apertured cavity resonator through which the beam of charged particles passes, first in one direction. A repeller electrode is provided to repel (or redirect) the beam after passage through the resonator back through the resonator in the other direction and in proper phase to reinforce the oscillations set up in
5220-441: The difference is perhaps more subtle. In keyboard instruments, the contact point along the string (whether this be hammer, tangent, or plectrum) is a choice made by the instrument designer. Builders use a combination of experience and acoustic theory to establish the right set of contact points. In harpsichords, often there are two sets of strings of equal length. These "choirs" usually differ in their plucking points. One choir has
5307-468: The dynamic and timbre (tone colour) range of orchestras, bands, and solo performances. String instruments can be divided into three groups: It is also possible to divide the instruments into categories focused on how the instrument is played. All string instruments produce sound from one or more vibrating strings , transferred to the air by the body of the instrument (or by a pickup in electronically amplified instruments). They are usually categorised by
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#17327803399205394-410: The extracted RF energy to the load, which may be a cooking chamber in a microwave oven or a high gain antenna in the case of radar. The klystron , tube waveguide, is a beam tube including at least two apertured cavity resonators. The beam of charged particles passes through the apertures of the resonators, often tunable wave reflection grids, in succession. A collector electrode is provided to intercept
5481-498: The fingerboard and the bridge. However, different bow placements can be selected to change timbre . Application of the bow close to the bridge (known as sul ponticello ) produces an intense, sometimes harsh sound, which acoustically emphasizes the upper harmonics . Bowing above the fingerboard ( sul tasto ) produces a purer tone with less overtone strength, emphasizing the fundamental , also known as flautando , since it sounds less reedy and more flute-like. Bowed instruments pose
5568-412: The fundamental frequency. They are then called overtones instead of harmonics . There may be several such series of resonant frequencies in a single resonator, corresponding to different modes of vibration. An electrical circuit composed of discrete components can act as a resonator when both an inductor and capacitor are included. Oscillations are limited by the inclusion of resistance, either via
5655-401: The guitar, bass, violin, etc.) can be played using a magnetic field. An E-Bow is a small hand-held battery-powered device that magnetically excites the strings of an electric string instrument to provide a sustained, singing tone reminiscent of a held bowed violin note. Third bridge is a plucking method where the player frets a string and strikes the side opposite the bridge. The technique
5742-419: The guitarist can produce sounds that cannot be produced with standard plucking and picking techniques. This technique was popularized by Jimi Hendrix and others in the 1960s. It was widely used in psychedelic rock and heavy metal music . There are three ways to change the pitch of a vibrating string . String instruments are tuned by varying a string's tension because adjusting length or mass per unit length
5829-478: The loudly amplified, highly distorted electric guitar was the key element of the early heavy metal music , with the distorted guitar being used in lead guitar roles, and with power chords as a rhythm guitar . The ongoing use of electronic amplification and effects units in string instruments, ranging from traditional instruments like the violin to the new electric guitar, added variety to contemporary classical music performances, and enabled experimentation in
5916-400: The next becomes significant. The vibrations in them begin to travel through the coupled harmonic oscillators in waves, from one oscillator to the next. The term resonator is most often used for a homogeneous object in which vibrations travel as waves, at an approximately constant velocity, bouncing back and forth between the sides of the resonator. The material of the resonator, through which
6003-402: The pitch of certain strings by increasing tension on them (stretching) through a mechanical linkage; release of the pedal returns the pitch to the original. Knee levers on the instrument can lower a pitch by releasing (and restoring) tension in the same way. A homemade washtub bass made out of a length of rope, a broomstick and a washtub can produce different pitches by increasing the tension on
6090-451: The player presses keys on to trigger a mechanism that sounds the strings, instead of directly manipulating the strings. These include the piano , the clavichord , and the harpsichord. With these keyboard instruments , strings are occasionally plucked or bowed by hand. Modern composers such as Henry Cowell wrote music that requires that the player reach inside the piano and pluck the strings directly, "bow" them with bow hair wrapped around
6177-491: The primitive technology and created "technically and artistically well-made harps, lyres, citharas, and lutes." Archaeological digs have identified some of the earliest stringed instruments in Ancient Mesopotamian sites, like the lyres of Ur , which include artifacts over three thousand years old. The development of lyre instruments required the technology to create a tuning mechanism to tighten and loosen
6264-557: The resonator. On the beamline of an accelerator system, there are specific sections that are cavity resonators for radio frequency (RF) radiation. The (charged) particles that are to be accelerated pass through these cavities in such a way that the microwave electric field transfers energy to the particles, thus increasing their kinetic energy and thus accelerating them. Several large accelerator facilities employ superconducting niobium cavities for improved performance compared to metallic (copper) cavities. The loop-gap resonator (LGR)
6351-468: The rim of the chamber are cylindrical cavities. The cavities are open along their length and so they connect with the common cavity space. As electrons sweep past these openings they induce a resonant high frequency radio field in the cavity, which in turn causes the electrons to bunch into groups. A portion of this field is extracted with a short antenna that is connected to a waveguide (a metal tube usually of rectangular cross section). The waveguide directs
6438-427: The rope (producing a higher pitch) or reducing the tension (producing a lower pitch). The frequency is proportional to the square root of the tension: The pitch of a string can also be varied by changing the linear density (mass per unit length) of the string. In practical applications, such as with double bass strings or bass piano strings, extra weight is added to strings by winding them with metal. A string with
6525-440: The same note. (Many notes on a piano are strung with a "choir" of three strings tuned alike, to increase the volume.) A guitar represents the second method—the player's fingers push the string against the fingerboard so that the string is pressed firmly against a metal fret. Pressing the string against a fret while plucking or strumming it shortens the vibrating part and thus produces a different note. Resonator A resonator
6612-531: The same time, a technique called a double stop .) Indeed, on the orchestral string section instruments, four strings are the norm, with the exception of five strings used on some double basses . In contrast, with stringed keyboard instruments, 88 courses are used on a piano , and even though these strings are arranged on a flat bridge, the mechanism can play any of the notes individually. Similar timbral distinctions are also possible with plucked string instruments by selecting an appropriate plucking point, although
6699-399: The second group, but the piano and harpsichord fall into the first. Hornbostel and Sachs' criterion for determining which sub-group an instrument falls into is that if the resonator can be removed without destroying the instrument, then it is classified as 31. The idea that the piano's casing, which acts as a resonator, could be removed without destroying the instrument, may seem odd, but if
6786-421: The sides is d {\displaystyle d\,} , the length of a round trip is 2 d {\displaystyle 2d\,} . To cause resonance, the phase of a sinusoidal wave after a round trip must be equal to the initial phase so the waves self-reinforce. The condition for resonance in a resonator is that the round trip distance, 2 d {\displaystyle 2d\,} ,
6873-533: The string tension. Lyres with wooden bodies and strings used for plucking or playing with a bow represent key instruments that point towards later harps and violin-type instruments; moreover, Indian instruments from 500 BC have been discovered with anything from 7 to 21 strings. In Vietnam, a 2,000 year old, singularly stringed instrument made of deer antler was also discovered. Musicologists have put forth examples of that 4th-century BC technology, looking at engraved images that have survived. The earliest image showing
6960-449: The string with the stick of the bow, a technique called col legno . This yields a percussive sound along with the pitch of the note. A well-known use of col legno for orchestral strings is Gustav Holst 's "Mars" movement from The Planets suite. The aeolian harp employs a very unusual method of sound production: the strings are excited by the movement of the air. Some instruments that have strings have an attached keyboard that
7047-513: The string. With bowed instruments, the player pulls a rosined horsehair bow across the strings, causing them to vibrate. With a hurdy-gurdy , the musician cranks a wheel whose rosined edge touches the strings. Bowed instruments include the string section instruments of the orchestra in Western classical music ( violin , viola , cello and double bass ) and a number of other instruments (e.g., viols and gambas used in early music from
7134-438: The strings in varying manners. Musicians play some string instruments, like guitars , by plucking the strings with their fingers or a plectrum (pick) , and others by hitting the strings with a light wooden hammer or by rubbing the strings with a bow , like violins . In some keyboard instruments, such as the harpsichord , the musician presses a key that plucks the string. Other musical instruments generate sound by striking
7221-419: The strings, or play them by rolling the bell of a brass instrument such as a trombone on the array of strings. However, these are relatively rarely used special techniques. Other keyed string instruments, small enough for a strolling musician to play, include the plucked autoharp , the bowed nyckelharpa , and the hurdy-gurdy, which is played by cranking a rosined wheel. Steel-stringed instruments (such as
7308-404: The technique used to make the strings vibrate (or by the primary technique, in the case of instruments where more than one may apply). The three most common techniques are plucking, bowing, and striking. An important difference between bowing and plucking is that in the former the phenomenon is periodic so that the overtones are kept in a strictly harmonic relationship to the fundamental. Plucking
7395-441: The walls of the cavity in or out, changing its size. The cavity magnetron is a vacuum tube with a filament in the center of an evacuated, lobed, circular cavity resonator. A perpendicular magnetic field is imposed by a permanent magnet. The magnetic field causes the electrons, attracted to the (relatively) positive outer part of the chamber, to spiral outward in a circular path rather than moving directly to this anode. Spaced about
7482-407: The waves flow, can be viewed as being made of millions of coupled moving parts (such as atoms). Therefore, they can have millions of resonant frequencies, although only a few may be used in practical resonators. The oppositely moving waves interfere with each other, and at its resonant frequencies reinforce each other to create a pattern of standing waves in the resonator. If the distance between
7569-468: The wooden bars in a xylophone , the head of a drum , the strings in stringed instruments , and the pipes in an organ . Some modify the sound by enhancing particular frequencies, such as the sound box of a guitar or violin . Organ pipes , the bodies of woodwinds , and the sound boxes of stringed instruments are examples of acoustic cavity resonators. The exhaust pipes in automobile exhaust systems are designed as acoustic resonators that work with
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