Pickup (music technology) - AbsoluteAstronomy.com

A pickup device is a transducer

Transducer

A transducer is a device that converts one type of energy to another. Energy types include electrical, mechanical, electromagnetic , chemical, acoustic or thermal energy. While the term transducer commonly implies the use of a sensor/detector, any device which converts energy can be considered a...

that captures mechanical vibrations, usually from suitably equipped stringed instruments such as the electric guitar

Electric guitar

An electric guitar is a guitar that uses the principle of direct electromagnetic induction to convert vibrations of its metal strings into electric audio signals. The signal generated by an electric guitar is too weak to drive a loudspeaker, so it is amplified before sending it to a loudspeaker...

, electric bass guitar

Bass guitar

The bass guitar is a stringed instrument played primarily with the fingers or thumb , or by using a pick....

, Chapman Stick

Chapman Stick

The Chapman Stick is an electric musical instrument devised by Emmett Chapman in the early 1970s. A member of the guitar family, the Chapman Stick usually has ten or twelve individually tuned strings and has been used on music recordings to play bass lines, melody lines, chords or textures...

, or electric violin

Electric violin

An electric violin is a violin equipped with an electronic output of its sound. The term most properly refers to an instrument purposely made to be electrified with built-in pickups, usually with a solid body...

, and converts them to an electrical signal that is amplified

Instrument amplifier

An instrument amplifier is an electronic amplifier that converts the often barely audible or purely electronic signal from musical instruments such as an electric guitar, an electric bass, or an electric keyboard into an electronic signal capable of driving a loudspeaker that can be heard by the...

, recorded, or broadcast

Broadcasting

Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...

Magnetic pickups

A magnetic pickup consists of a permanent magnet with a core of material such as alnico

Alnico

Alnico is an acronym referring to iron alloys which in addition to iron are composed primarily of aluminium , nickel and cobalt , hence al-ni-co, with the addition of copper, and sometimes titanium. Alnico alloys are ferromagnetic, with a high coercivity and are used to make permanent magnets...

, wrapped with a coil

Coil

A coil is a series of loops. A coiled coil is a structure in which the coil itself is in turn also looping.-Electromagnetic coils:An electromagnetic coil is formed when a conductor is wound around a core or form to create an inductor or electromagnet...

of several thousand turns of fine enameled copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

wire. The pickup is most often mounted on the body of the instrument, but can be attached to the bridge

Bridge (instrument)

A bridge is a device for supporting the strings on a stringed instrument and transmitting the vibration of those strings to some other structural component of the instrument in order to transfer the sound to the surrounding air.- Explanation :...

, neck and/or pickguard, as on many electro-acoustic archtop jazz guitars and string basses. The vibration of the nearby soft-magnetic

Magnet

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.A permanent magnet is an object...

strings modulate

Modulation

In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...

s the magnetic flux

Magnetic flux

Magnetic flux , is a measure of the amount of magnetic B field passing through a given surface . The SI unit of magnetic flux is the weber...

linking the coil, thereby inducing

Faraday's law of induction

Faraday's law of induction dates from the 1830s, and is a basic law of electromagnetism relating to the operating principles of transformers, inductors, and many types of electrical motors and generators...

an alternating current through the coil of wire. This signal is then carried to amplification

Instrument amplifier

or recording equipment via a cable

Cable

A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...

. There may also be an internal preamplifier

Preamplifier

A preamplifier is an electronic amplifier that prepares a small electrical signal for further amplification or processing. A preamplifier is often placed close to the sensor to reduce the effects of noise and interference. It is used to boost the signal strength to drive the cable to the main...

stage between the pickup and cable. More generally, the pickup operation can be described using the concept of a magnetic circuit

Magnetic circuit

A magnetic circuit is made up of one or more closed loop paths containing a magnetic flux. The flux is usually generated by permanent magnets or electromagnets and confined to the path by magnetic cores consisting of ferromagnetic materials like iron, although there may be air gaps or other...

, in which the motion of the string varies the magnetic reluctance

Magnetic reluctance

Magnetic reluctance, or magnetic resistance, is a concept used in the analysis of magnetic circuits. It is analogous to resistance in an electrical circuit, but rather than dissipating magnetic energy it stores magnetic energy...

in the circuit created by the permanent magnet.

Output

The output voltage of pickups varies between 100 mV rms

Root mean square

In mathematics, the root mean square , also known as the quadratic mean, is a statistical measure of the magnitude of a varying quantity. It is especially useful when variates are positive and negative, e.g., sinusoids...

to over 1 V rms for some of the higher output types. Measurements taken with an Oscilloscope with a hard strum on all 6 guitar strings can produce a larger output voltage swing, typically peak voltages of +/- 5 volts for single coil pickups and +/- 10 volt peaks on dual coil pickups. Some high-output pickups achieve this by employing very strong magnets, thus creating more flux and thereby more output. This can be detrimental to the final sound because the magnet's pull on the strings can cause problems with intonation as well as damp

Damping

In physics, damping is any effect that tends to reduce the amplitude of oscillations in an oscillatory system, particularly the harmonic oscillator.In mechanics, friction is one such damping effect...

the strings and reduce sustain. Other high-output pickups have more turns of wire to increase the voltage generated by the string's movement. However, this also increases the pickup's output resistance/impedance, which can affect high frequencies if the pickup is not isolated by a buffer amplifier

Buffer amplifier

A buffer amplifier is one that provides electrical impedance transformation from one circuit to another...

or a DI unit

DI unit

A DI unit, DI box, Direct Box, or simply DI , is a device typically used in recording studios to connect a high-impedance, line level, unbalanced output signal to a low-impedance microphone level balanced input, usually via XLR connector...

Pickup sound

The turns of wire in proximity to each other have an equivalent self-capacitance

Capacitance

In electromagnetism and electronics, capacitance is the ability of a capacitor to store energy in an electric field. Capacitance is also a measure of the amount of electric potential energy stored for a given electric potential. A common form of energy storage device is a parallel-plate capacitor...

that, when added to any cable capacitance present, resonates with the inductance

Inductance

In electromagnetism and electronics, inductance is the ability of an inductor to store energy in a magnetic field. Inductors generate an opposing voltage proportional to the rate of change in current in a circuit...

of the winding. This resonance

Resonance

In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...

can accentuate certain frequencies, giving the pickup a characteristic tonal quality. The more turns of wire in the winding, the higher the output voltage but the lower this resonance frequency

Resonance

In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...

. The inductive source impedance inherent in this type of transducer

Transducer

makes it less linear than other forms of pickups, such as piezo-electric or optical. The tonal quality produced by this nonlinearity is, however, subject to taste, and some guitarists and luthiers consider it aesthetically superior to a more linear transducer.

The external load usually consists of resistance (the volume and tone potentiometer

Potentiometer

A potentiometer , informally, a pot, is a three-terminal resistor with a sliding contact that forms an adjustable voltage divider. If only two terminals are used , it acts as a variable resistor or rheostat. Potentiometers are commonly used to control electrical devices such as volume controls on...

in the guitar, and any resistance to ground at the amplifier input) and capacitance between the hot lead and shield in the guitar cable. The electric cable also has a capacitance, which can be a significant portion of the overall system capacitance. This arrangement of passive components forms a resistively-damped second-order low-pass filter

Electronic filter

Electronic filters are electronic circuits which perform signal processing functions, specifically to remove unwanted frequency components from the signal, to enhance wanted ones, or both...

. Pickups are usually designed to feed a high input impedance

Input impedance

The input impedance of an electrical network is the equivalent impedance "seen" by a power source connected to that network. If the source provides known voltage and current, such impedance can be calculated using Ohm's Law...

, typically a megohm

Ohm

The ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.- Definition :The ohm is defined as a resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere,...

or more, and a low impedance load reduces the high-frequency response of the pickup because of the filtering effect of the inductance.

Humbuckers

Classic single coil pickups (in contrast to modern, noiseless single coil designs) also act like an antenna and are prone to pick up mains hum

Mains hum

Mains hum, electric hum, or power line hum is an audible oscillation of alternating current at the frequency of the mains electricity, which is usually 50 Hz or 60 Hz, depending on the local power line frequency...

(nuisance electromagnetic interference generated by electrical power cables, power transformers, and fluorescent light ballasts in the area) along with the musical signal. Mains hum consists of a fundamental signal at a nominal 50 or 60 Hz, depending on local alternating current

Alternating current

In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

frequency, and usually some harmonic content. The changing magnetic flux caused by the mains current links with the windings of the pickup, inducing a voltage by transformer

Transformer

A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

action. The pickups also are sensitive to the electromagnetic field from nearby cathode ray tubes in video monitors or televisions.

To overcome this effect, the humbucking

Humbucker

A humbucker is a type of electric guitar pickup, first patented by Seth Lover and the Gibson company, that uses two coils, both generating string signal. Humbuckers have higher output than a single coil pickup since both coils are connected in series...

pickup was invented by Raymond J. Butts, but Seth Lover

Seth Lover

Seth Lover is most famous for inventing the humbucker or hum-cancelling electric stringed instrument pickup, most often used on the electric guitar....

of Gibson

Gibson Guitar Corporation

The Gibson Guitar Corporation, formerly of Kalamazoo, Michigan and currently of Nashville, Tennessee, manufactures guitars and other instruments which sell under a variety of brand names...

was also working on one himself. Ray Butts initially developed one on his own and later worked with Gretsch

Gretsch

The Gretsch Company was founded in 1883 by Friedrich Gretsch, a twenty-seven year old German immigrant recently arrived in the US. Friedrich Gretsch manufactured banjos, tambourines, and drums, until his death in 1895. His son, Fred, moved operations to Brooklyn, New York in 1916...

. Who developed it first is a matter of some debate, but Ray Butts was awarded the first patent and Seth Lover came next . Ultimately, both men developed essentially the same concept, but Ray Butts was never recognized as the true First. Another way to reduce nuisance hum when recording with humbuckers or single coils is to aim the instrument's neck in a different direction to find a location that minimizes the received noise signal.

A humbucking pickup, shown in the image on the right, is composed of two coils. Each coil is wound reverse to one another. However, the six magnetic poles are opposite in polarity in each winding. Since ambient hum from power-supply transformers, radio frequencies, or electrical devices reaches the coils as common-mode noise

Common-mode interference

In telecommunication, the term common-mode interference has the following meanings:#Interference that appears on both signal leads , or the terminals of a measuring circuit, and ground....

, it induces an electrical current of equal magnitude in each coil. Because the windings are reversed in each pickup coil, the electro-magnetic interference sine wave signals in each pickup are equal and in antiphase, resulting in them canceling each other. However, the signal from the guitar string is doubled, due to the phase reversal caused by the out of phase magnets. The magnets being out of phase in conjunction with the coil windings being out of phase put the guitar string signal from each pickup in phase with one another. Therefore, the voltage of the signal is approximately doubled, if the two coils are connected in series.

When wired in series, as is most common, the overall inductance

Inductance

of the pickup is increased, which lowers its resonance frequency and attenuates the higher frequencies, giving a less trebly tone (i.e., "fatter") than either of the two component single-coil pickups would give alone. Because the two coils are wired in series, the resulting signal that is output by the pickup is larger in amplitude, thus more able to overdrive the early stages of the amplifier.

An alternative wiring places the coils in buck parallel. The equal common-mode mains hum interference cancels, while the string variation signal sums. This method has a more neutral effect on resonant frequency: mutual capacitance is doubled (which if inductance were constant would lower the resonant frequency), and inductance is halved (which would raise the resonant frequency without the capacitance change). The net is no change in resonant frequency. This pickup wiring is rare, as guitarists have come to expect that humbucking 'has a sound', and is not neutral. On fine jazz guitars, the parallel wiring produces significantly cleaner sound, as the lowered source impedance drives capacitive cable with lower high frequency attenuation.

A side-by-side humbucking pickup senses a wider section of the string (has a wider aperture) than a single-coil pickup. This affects tone. By picking up a larger portion of the vibrating string more lower harmonics are present in the signal produced by the pickup in relation to high harmonics, resulting in a "fatter" tone. Humbucking pickups in the narrow form factor of a single coil, designed to replace single-coil pickups, have the narrower aperture resembling that of a single coil pickup. Some models of these single-coil-replacement humbuckers produce more authentic resemblances to classic single coil tones than full-size humbucking pickups of a similar inductance, which shows that the amount of high-frequency rolloff due to coil inductance is not the only factor in that sound.

Construction

Pickups have magnetic polepieces (with the notable exceptions of rail and lipstick tube pickups—one or two for each string. These polepiece centers should perfectly align with the strings, or sound is suboptimal as the pickup would capture only a part of the string's vibrational energy. An exception to this rule are the J- and P-style pickups (found on the Fender Jazz Bass

Fender Jazz Bass

The Jazz Bass was the second model of electric bass created by Leo Fender. The bass is distinct from the Precision Bass in that its tone is brighter and richer in the midrange and treble with less emphasis on the fundamental harmonic...

and Precision Bass

Fender Precision Bass

The Fender Precision Bass is an electric bass.Designed by Leo Fender as a prototype in 1950 and brought to market in 1951, the Precision was the first electric bass to earn widespread attention and use. A revolutionary instrument for the time, the Precision Bass has made an immeasurable impact on...

, respectively) where the two polepieces per string are positioned on either side of each string.

String spacing is not even on most guitars: it starts with minimal spacing at nut and ends with maximal at bridge. Thus, bridge, neck and middle pickups usually have different polepiece spacing on the same guitar.

There are several standards on pickup sizes and string spacing between the poles. Spacing is measured either as a distance between 1st to 6th polepieces' centers (this is also called "E-to-E" spacing), or as a distance between adjacent polepieces' centers.

	1st-to-6th	Adjacent
Standard spacing (Vintage Gibson guitars)	1.90" 48 mm	0.380" 9.6 mm
F-spacing (Most Fender guitars, modern Gibson, Floyd Rose Floyd Rose The Floyd Rose Locking Tremolo, or simply Floyd Rose, is a type of locking vibrato arm for a guitar. The first of its kind, Floyd D. Rose invented the locking vibrato in 1977, and it is now manufactured by a company of the same name... bridges)	2.01" 51 mm	0.402" 10.2 mm
Very close to bridge, extra pickup (Roland guitar synth hex pickups)	2.060" 52.3 mm	0.412" 10.5 mm
Telecaster spacing (Fender Telecaster guitars)	2.165" 55 mm	0.433" 11 mm
Steinberger Spirit GT-Pro spacing (may be typical for other Steinberger guitars)	2.362" 60 mm	0.3937" 10 mm

Notation

Usually an electric guitar has more than one magnetic pickup. A combination of pickups is called a pickup configuration. It is usually notated by just writing out the pickup types, using "S" for single-coil and "H" for humbucker, in order from bridge pickup to neck pickup. Popular pickup configurations include:
Less frequently found configurations are:

S (Fender Esquire, early Gibson Les Paul
Gibson Les Paul
The Gibson Les Paul was the result of a design collaboration between Gibson Guitar Corporation and the late jazz guitarist and electronics inventor Les Paul. In 1950, with the introduction of the Fender Telecaster to the musical market, electric guitars became a public craze. In reaction, Gibson...

Juniors, Gibson Melody Maker
Gibson Melody Maker
In 2007, the Melody Maker became a separate model. It now has a smaller single-coil pickup than the P-90, a wraparound bridge/tailpiece unit, a mahogany neck, and a pickguard similar to the original Melody Maker...

, some Telecasters)
H (some hollow body guitars like Gibson ES-165 Herb Ellis; minimalistic rock/metal guitars like Kramer Baretta
Kramer Guitars
Kramer Guitars is an American manufacturer of electric guitars and basses. Kramer produced aluminum-necked electric guitars and basses in the 1970s and wooden-necked guitars catering to hard rock and heavy metal musicians in the 1980s; Kramer is currently a division of Gibson Guitar Corporation...

; later Les Paul Juniors)
H-S (minimalistic guitars like Hamer Californian Deluxe
Hamer Guitars
Hamer Guitars is an American manufacturer of electric guitars. Founded in 1973 by vintage guitar shop owners, Jol Dantzig and his business partner Paul Hamer. Early instruments featured guitar designs based on the Gibson Explorer and Flying V...

and Les Paul BFG, entry-level guitars like Squier '51
Squier '51
The Squier '51 was an electric guitar made by Squier, a subsidiary of Fender. The '51 is notable for being one of the few original designs made by Squier, which normally manufactures less expensive authorized copies of Fender's popular guitars and bass guitars....

)

Examples of rare configurations that only a few particular models use include:

H-H-H (some Gibson Les Paul
Gibson Les Paul
The Gibson Les Paul was the result of a design collaboration between Gibson Guitar Corporation and the late jazz guitarist and electronics inventor Les Paul. In 1950, with the introduction of the Fender Telecaster to the musical market, electric guitars became a public craze. In reaction, Gibson...

Gold Tops and Customs, Gibson SG-3
Gibson SG
At the launch of the SG in 1961, Gibson offered four variants of the SG; the SG Junior , the SG Special, the SG Standard, and the top-of-the-line SG Custom. However, Gibson's current core variants as of 2010 are the SG Standard and the SG Special...

, Gibson ES-5 Switchmaster
Gibson ES-5
The Gibson ES-5 is a guitar produced by the Gibson Guitar Corporation as part of the ES, or "Electric Spanish" series of guitars. The ES-5 was intended to be an electric version of their popular Gibson L-5 acoustic jazz model. The ES-5 was introduced in 1949, and offered several innovative...

(after 1957), Kramer Jersey Star
Kramer Guitars
Kramer Guitars is an American manufacturer of electric guitars and basses. Kramer produced aluminum-necked electric guitars and basses in the 1970s and wooden-necked guitars catering to hard rock and heavy metal musicians in the 1980s; Kramer is currently a division of Gibson Guitar Corporation...

, Ibanez Destroyer
Ibanez Destroyer
The Destroyer is an Ibanez brand electric guitar model manufactured at the FujiGen-Gakki musical instrument factory for the Hoshino-Gakki Company. The Destroyer model was first introduced by Hoshino-Gakki in 1975 and was based on the Gibson Musical Instruments' Explorer design...

, Ibanez
Ibanez
is a Japanese guitar brand owned by Hoshino Gakki. Based in Nagoya, Aichi, Japan, Hoshino Gakki were one of the first Japanese musical instrument companies to gain a significant foothold in import guitar sales in the United States and Europe, as well as the first brand of guitars to mass produce...

PGM200
Paul Gilbert
Paul Brandon Gilbert is an American guitarist. He is well known for his technical guitar work with Racer X and Mr...

)
H-S-S-H (Music Man Steve Morse
Steve Morse
Steven J. "Steve" Morse is an American guitarist and composer, best known for his work in the hard rock band Deep Purple since 1994. He began his career to form the unique styled instrumental rock band Dixie Dregs in the 1970. Morse's musical inspiration comes from country, funk, jazz fusion, and...

Signature)
H-H-S (some ESP Stephen Carpenter Models and Alembic Jerry Garcia Models)
H-H (some early seven-string ESP horizon models. But unlike the regular H-H setup, the humbuckers are in the Middle and bridge position)
S-H-S (Fender Wayne Kramer
Wayne Kramer (guitarist)
Wayne Kramer is an American guitarist, singer, songwriter, producer and film and television scorer....

Signature)
S-H (Some Telecasters have this configuration.)
H-S (one model of the Fender Jazzmaster. The Ibanez RG2011SC, but with the single coil in the middle, rather than the neck position.)
H-S-S (The Hamer phantom has this configuration but instead has an angled neck pickup and there is no space between the middle single coil and the bridge humbucker.)

Sensors

Many semi-acoustic

Semi-acoustic guitar

A semi-acoustic guitar or hollow-body electric is a type of electric guitar with both a sound box and one or more electric pickups. This is not the same as an electric acoustic guitar, which is an acoustic guitar with the addition of pickups or other means of amplification, either added by the...

and acoustic guitars, and some electric guitars and basses, have been fitted with piezoelectric

Piezoelectricity

Piezoelectricity is the charge which accumulates in certain solid materials in response to applied mechanical stress. The word piezoelectricity means electricity resulting from pressure...

pickups instead of, or in addition to, magnetic pickups. These have a very different sound, and also have the advantage of not picking up any other magnetic fields, such as mains hum and feedback

Feedback

Feedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...

from monitoring loops. In hybrid guitar

Hybrid guitar

A hybrid guitar is an electric guitar with the ability to produce a signal with the tonal quality of an acoustic guitar in addition to a typical electric signal from a magnetic pickup, allowing a wide tonal pallette performers with a varied repertoire...

s, this system allows switching between magnetic pickup and piezo sounds, or simultaneously blending the output. Solid bodied guitars with only a piezo pickup are known as silent guitar

Silent guitar

A silent guitar is a type of guitar with a solid or chambered body that converts the vibration of the strings into electric current using a piezoelectric pickup. The body of the guitar does not amplify the vibration of the strings into audible sound...

s, which are usually used for practicing by acoustic guitarists. Piezo pickups can be also built into electric guitar bridges for conversion of existing instruments.

Most pickups for bowed string instruments, such as cello, violin, and double bass, are piezoelectric. These may be inlaid into the bridge

Bridge (instrument)

, laid between the bridge feet and the top of the instrument, or, less frequently, wedged under a wing of the bridge. Some pickups are fastened to the top of the instrument with removable putty

Blu-Tack

Blu-Tack is a versatile, reusable putty-like pressure-sensitive adhesive produced by Bostik, commonly used to attach papers to walls or other surfaces....

Preamps

Piezoelectric pickups have a very high output impedance

Output impedance

The output impedance, source impedance, or internal impedance of an electronic device is the opposition exhibited by its output terminals to an alternating current of a particular frequency as a result of resistance, inductance and capacitance...

and appear as a capacitance

Capacitance

in series with a voltage source

Voltage source

In electric circuit theory, an ideal voltage source is a circuit element where the voltage across it is independent of the current through it. A voltage source is the dual of a current source. In analysis, a voltage source supplies a constant DC or AC potential between its terminals for any current...

. They therefore often have an instrument-mounted buffer amplifier

Buffer amplifier

A buffer amplifier is one that provides electrical impedance transformation from one circuit to another...

fitted to maximize full frequency response

Frequency response

Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system. It is a measure of magnitude and phase of the output as a function of frequency, in comparison to the input...

. Piezo pickups are usually mounted under the bridge

Bridge (instrument)

and sometimes form part of the bridge assembly itself.

The piezo pickup gives a very wide frequency range output compared to the magnetic types and can give large amplitude

Amplitude

Amplitude is the magnitude of change in the oscillating variable with each oscillation within an oscillating system. For example, sound waves in air are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation...

signals from the strings. For this reason, the buffer amplifier is often powered from relatively high voltage rails (about ±9 V) to avoid distortion

Distortion

A distortion is the alteration of the original shape of an object, image, sound, waveform or other form of information or representation. Distortion is usually unwanted, and often many methods are employed to minimize it in practice...

due to clipping

Clipping (audio)

Clipping is a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability...

. Some musicians prefer a preamp that isn't as linear (like a single-FET amplifier) in which the clipping is "softer". Such an amplifier starts to distort sooner, which makes the distortion less "buzzy" and less audible than a more linear, but less forgiving op-amp. However, at least one study indicates that most people can not tell the difference between FET and op-amp circuits in blind listening comparisons of electric instrument preamps, which correlates with results of formal studies of other types of audio devices. Sometimes, piezoelectric pickups are used in conjunction with magnetic types to give a wider range of available sounds.

For early pick-up devices using the piezoelectric effect, see phonograph.

Other transducers

Some pickup products are installed and used similarly to piezoelectric pickups, but use different underlying technology, for instance electret

Electret

Electret is a dielectric material that has a quasi-permanent electric charge or dipole polarisation. An electret generates internal and external electric fields, and is the electrostatic equivalent of a permanent magnet. Oliver Heaviside coined this term in 1885...

or condenser microphone technology.

Multi-transducer pickups

Hexaphonic pickups (also called divided pickups and polyphonic
Polyphony (instrument)
Polyphony Instruments that are not capable of polyphony are monophonic.-Synthesizer:Most of early synthesizers were monophonic musical instruments which can play only one note at a time, and are often called monosynth as opposed to polysynth...

pickups) have a separate output for each string (Hexaphonic assumes six strings, as on a guitar). This allows for separate processing and amplification for each string. It also allows a converter to sense the pitch coming from individual string signals for producing note commands, typically according to the MIDI (musical instrument digital interface) protocol. A hexaphonic pickup and a converter are usually components of a guitar/synthesizer

Guitar/synthesizer

A guitar synthesizer is any one of a number of musical instrument systems that allow a guitar player to play synthesizer sound. While the term "MIDI guitar" is often used as a synonym for the field of guitar/synthesis or for a guitar/synthesizer, MIDI is not always used...

.

Such pickups are uncommon (compared to normal ones), and only a few notable models exist. Hexaphonic pickups can be either magnetic or piezoelectric.

Optical

Optical pickups are a fairly recent development that work by sensing the interruption of a light beam by the string. The light source is usually an LED, and the detector is a photodiode

Photodiode

A photodiode is a type of photodetector capable of converting light into either current or voltage, depending upon the mode of operation.The common, traditional solar cell used to generateelectric solar power is a large area photodiode....

or phototransistor. These pickups have complete insensitivity to magnetic or electric interference and also have a very wide and flat frequency response, unlike magnetic pickups.

Optical pickup guitars were first shown at the 1969 NAMM in Chicago, by Ron Hoag.

Active and passive pickups

Pickups can be either active or passive

Passivity (engineering)

Passivity is a property of engineering systems, used in a variety of engineering disciplines, but most commonly found in analog electronics and control systems...

. Pickups, apart from optical types, are inherently passive transducers. "Active" pickups incorporate electronic circuitry to modify the signal. "Passive" pickups are usually wire wound around a magnet, and are the most common type used. They can generate electric potential

Electric potential

In classical electromagnetism, the electric potential at a point within a defined space is equal to the electric potential energy at that location divided by the charge there...

without need for external power, though their output is relatively low, and the harmonic content of output depends greatly on the winding.

Active pickups require an electrical source of energy (usually one or two 9V batteries) to operate and include an electronic preamp, active filters, active EQ

Equalization

Equalization, is the process of adjusting the balance between frequency components within an electronic signal. The most well known use of equalization is in sound recording and reproduction but there are many other applications in electronics and telecommunications. The circuit or equipment used...

and other sound-shaping features. They can sometimes give much higher possible output. They also are less affected in tone by varying lengths of the electric cable connecting the guitar to the amplifier, and amplifier input characteristics. Magnetic pickups used with 'active' circuitry usually feature a lower inductance (and initially lower output) winding that tends to give a flatter frequency response curve.

The disadvantages of active pickup systems (pickups->preamp) are the power source (usually either a battery

Battery (electricity)

An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

or phantom power

Phantom power

Phantom power, in the context of professional audio equipment, is a method for transmitting DC electric power through microphone cables to operate microphones that contain active electronic circuitry....

) and higher cost. They are more popular on electric bass, because of their solid tone and improved clarity; most high-end basses feature active pickup systems. Most piezoelectric and all optical pickups are active and include some sort of preamp.

The main advantages of active bass pickup systems is their cleaner, clearer more "Hi Fi" sound. Many players, notably Stanley Clarke

Stanley Clarke

Stanley Clarke is an American jazz musician and composer known for his innovative and influential work on double bass and electric bass guitar as well as for his numerous film and television scores...

, Flea

Flea (musician)

Michael Peter Balzary , better known by his stage name Flea, is an Australian-American musician and occasional actor. He is best known as the bassist, co-founding member, and one of the composers of the rock band Red Hot Chili Peppers...

, Victor Wooten

Victor Wooten

Victor Lemonte Wooten is an American bass player, composer, author, and producer, and has been the recipient of five Grammy Awards....

, Abraham Laboriel

Abraham Laboriel

Abraham Laboriel, Sr. is a Mexican bassist of Garifuna descent who has played on over 4,000 recordings and soundtracks. Guitar Player Magazine described him as "the most widely used session bassist of our time". Laboriel is the father of drummer Abe Laboriel Jr. and of producer, songwriter, and...

and Doug Wimbish

Doug Wimbish

Doug Wimbish is a bass player, primarily known for his studio work for the rap/hip hop label Sugarhill Records and his membership of the funk metal band Living Colour. He has played for a vast range of artists, including Jeff Beck, Mick Jagger, Madonna, George Clinton, Paula Cole, Bomb the Bass,...

have used active bass pickups to produce their characteristic bass tones.

They also allow more "headroom" and dynamic range. Good quality active systems produce less noise and hum compared to their passive counterparts.

Stereo and multiple pickups with individual outputs

Rickenbacker

Rickenbacker International Corporation, also known as Rickenbacker, is an electric and bass guitar manufacturer based in Santa Ana, California...

was the first manufacturer who began producing stereo bass guitars with a stereo output for each pickup section. The neck pickup had one output and the bridge pickup had one. Also Teisco

Teisco

Teisco was a Japanese manufacturer of affordable musical instruments from 1948 until 1969, and now its brand is owned by Kawai Musical Instruments Manufacturing Co. Ltd. . The company produced guitars as well as keyboard instruments, microphones, amplifiers and even drums...

produced a guitar with a stereo option. Teisco divided the two sections in the upper three strings and the lower three strings for each individual output. The Gittler guitar

Gittler guitar

A Gittler Guitar is an experimental designed guitar created by Allan Gittler . Gittler felt that sentimental design references to acoustic guitars are unnecessary in an electronically amplified guitar, and designed his instrument with the objective of reducing the electric guitar to the most...

was an experimental guitar with six pickups, one for each string, with six outputs. The Go! Team

The Go! Team

The Go! Team are a six-piece band from Brighton, England. They combine indie rock and garage rock with a mixture of blaxploitation and Bollywood soundtracks, double dutch chants, old school hip hop and distorted guitars similar to the style of Sonic Youth. Their songs are a mix of live...

has modified a Fender Telecaster

Fender Telecaster

The Fender Telecaster, colloquially known as the Tele , is typically a dual-pickup, solid-body electric guitar made by Fender.Its simple yet effective design and revolutionary sound broke ground and set trends in electric guitar manufacturing and popular music...

with an additional rotated pickup for the upper string, causing a simulation of a one string bass sound.

External links

Guitar Pickup Simulation
Guitar Pickup - Interactive Java Tutorial National High Magnetic Field Laboratory
Properties of Magnetic Materials (chapter)
Basic Electric Guitar Circuits - Pickups

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Magnetic pickups

Output

Pickup sound

Humbuckers

Construction

Notation

Sensors

Preamps

Other transducers

Multi-transducer pickups

Optical

Active and passive pickups

Stereo and multiple pickups with individual outputs

See also

External links