Pickup (music technology)

Source: Wikipedia, the free encyclopedia.
(Redirected from
Magnetic pickup
)
single coils
.

A pickup is a

recorded
directly.

The first electrical string instrument with pickups, the "Frying Pan" slide guitar, was created by George Beauchamp and Adolph Rickenbacker around 1931.[1]

Most electric guitars and electric basses use

piezoelectric pickup.[citation needed
]

Magnetic pickups

A typical magnetic pickup is a transducer (specifically a

mV peak) for one string and 128 mV RMS (850 mV peak) for a chord.[4]

The pickup is connected with a

recording
equipment via a patch cable.

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

humbuckers. A special type of humbucker characteristic for Precision type bass guitars is called split coil pickup: two coils, each of them picks up different strings, on a 4-string bass, one coil the E and A string, the second coil the D and G string.[5]
The pickup is one of the most important aspects to distinguishing an electric guitar's sound. Most guitar models have a distinction in pickups, which act as a new selling point for guitar companies.

Construction

Split pole pickups, Fender Jazz Bass

Pickups have magnetic polepieces, typically one or two for each string, with the notable exceptions of rail and lipstick tube pickups. Single polepieces are approximately centered on each string whereas dual polepieces such as the standard pickups on the Fender Jazz Bass and Precision Bass sit either side of each string.

On most guitars, the strings are not fully parallel: they converge at the nut and diverge at the bridge. Thus, bridge, neck and middle pickups usually have different polepiece spacings 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 bridges)
2.01"
51 mm
0.402"
10.2 mm
Very close to bridge, extra pickup
(Roland GK series hexaphonic)
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

Output

Some high-output pickups employ 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 (called string capture

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 and impedance, which can affect high frequencies if the pickup is not isolated by a buffer amplifier or a DI unit.

Pickup sound

Single coil pickups, Fender Stratocaster (1963)

The turns of wire in proximity to each other have an equivalent self-capacitance that, when added to any cable capacitance present, resonates with the inductance of the winding. This resonance can accentuate certain frequencies, giving the pickup a characteristic tonal quality. The more turns of wire in the winding, the higher the output voltage[7] but the lower this resonance frequency.

The arrangement of parasitic resistances and capacitances in the guitar, cable, and amplifier input, combined with the inductive

low-pass filter, producing a non-linearity effect not found in piezoelectric or optical transducers. Pickups are usually designed to feed a high input impedance, typically a megohm
or more, and a low-impedance load increases attenuation of higher frequencies. Typical maximum frequency of a single-coil pickup is around 5 kHz, with the highest note on a typical guitar fretboard having a fundamental frequency of 1.17 kHz.

Humbuckers

PRS's Dragon humbucker

Single-coil pickups act like a directional antenna and are prone to pick up mains hum—nuisance alternating current electromagnetic interference from electrical power cables, power transformers, fluorescent light ballasts, video monitors or televisions—along with the musical signal. Mains hum consists of a fundamental signal at a nominal 50 or 60 Hz, depending on local current frequency, and usually some harmonic content.

To overcome this, the

Gibson.[8] Who developed it first is a matter of some debate, but Butts was awarded the first patent (U.S. patent 2,892,371) and Lover came next (U.S. patent 2,896,491
).

A humbucking pickup is composed of two coils, with each coil wound reverse to the other. Each set of six magnetic poles is also opposite in polarity. Since ambient hum from electrical devices reaches the coils as

common-mode noise
, it induces an equal voltage in each coil, but 180 degrees out of phase between the two voltages. These effectively cancel each other, while the signal from the guitar string is doubled.

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

An alternative wiring places the coils in buck parallel, which has a more neutral effect on resonant frequency. This pickup wiring is rare,[9] as guitarists have come to expect that humbucking pickups 'have a sound', and are not so neutral. On fine jazz guitars, the parallel wiring produces significantly cleaner sound,[9] as the lowered source impedance drives capacitive cable with lower high frequency attenuation.

A side-by-side humbucking pickup senses a wider section of each string than a single-coil pickup.[10] 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.

Notation

Most electric guitars have two or three magnetic pickups. A combination of pickups is called a pickup configuration, usually notated by writing out the pickup types in order from bridge pickup through mid pickup(s) to neck pickup, using “S” for single-coil and “H” for humbucker. Typically the bridge pickup is known as the lead pickup, and the neck pickup is known as the rhythm pickup.[11]

Common pickup configurations include:

Less frequently found configurations are:

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

  • H-S, but with single coil in the middle (one model of Fender Jazzmaster, Ibanez RG2011SC, Fender Player Jaguar)
  • H-S-S, but with no space between the middle single coil and the bridge humbucker (Hamer Phantom with angled neck pickup)
  • H-H-S (Mayones Legend “22” Anders Nyström signature, some ESP Stephen Carpenter Models, and Alembic Jerry Garcia Models)
  • H-S-S-H (Music Man Steve Morse Signature)
  • S-H (some Telecasters, Music Man “Valentine” James Valentine signature)
  • S-H-H (some early seven-string ESP Horizons)
  • S-H-S (Fender Wayne Kramer Signature)

Piezoelectric pickups

Sensors

Piezoelectric pickup on a classical acoustic guitar
Piezoelectric pickup on a classical acoustic guitar
Dual pickup by peterman.com.au in Australia
Dual pickup by Peterman in Australia
Piezoelectric violin bridge pickup
Piezoelectric violin bridge pickup

The piezoelectric pickup contains a piezo crystal, which converts the vibrations directly to a changing voltage.

Many

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

putty
.

Preamps

Piezoelectric pickups have a very high output impedance and appear as a capacitance in series with a voltage source. They therefore often have an instrument-mounted buffer amplifier fitted to maximize frequency response.

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

op-amp.[citation needed] However, at least one study[13]
indicates that most people cannot 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 pickup 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

condenser microphone technology.[15]

Double systems pickups

There are basically four principles used to convert sound into an alternating current, each with their pros and cons:

  1. A
    crosstalk
    .
  2. Contact pickups register the vibrations of the instrument itself. They have the advantage of producing little feedback and no crosstalk at all. In spite of their lesser sound quality and thanks to their low price, contact pickups (and especially the piezoelectric pickup) have become the most popular transducer.
  3. Magnetic pickups. Magnetic pickups, as applied in electric guitars, register the vibrations of nickel or steel strings in a magnetic field. They have the advantage that they can be connected directly to an (electric guitar) amplifier, but in combination with a steel-string acoustic guitar the sound tends to be electric. This is why acoustic guitarists typically choose a piezoelectric pickup, built in microphone, or both.
  4. Electrostatic pickups. Another way is to use the changing capacitance between the string and a pickup plate. These electronic pickups produce much higher dynamics than conventional pickups, so the difference between a soft and a loud pick strike is more pronounced than with other types of pickups.

An amplification system with two transducers combines the qualities of both. A combination of a microphone and a piezoelectric pickup typically produces better sound quality and less sensitivity to feedback, as compared to single transducers. However, this is not always the case. A less frequently used combination is a piezoelectric and a magnetic pickup. This combination can work well for a solid sound with dynamics and expression. Examples of a double system amplifier are the Highlander iP-2, the Verweij VAMP or the LR Baggs dual source and the D-TAR Multisource.[16]

Multi-transducer pickups

Hexaphonic pickups (also called divided pickups and

guitar/synthesizer
.

Such pickups are uncommon (compared to normal ones), and only a few notable models exist, like the piezoelectric pickups on the Moog Guitar. Hexaphonic pickups can be either magnetic or piezoelectric or based on the condensor principle like electronicpickups

Optical

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

phototransistor.[17]
These pickups are completely resistant to magnetic or electric interference and also have a very broad and flat frequency response, unlike magnetic pickups.

Optical pickup guitars were first shown at the 1969

Chicago, by Ron Hoag.[18]

In 2000, Christopher Willcox, founder of LightWave Systems, unveiled a new beta technology for an optical pickup system using infrared light. In May 2001, LightWave Systems released their second generation pickup, dubbed the "S2."[19]

Active and passive pickups

EMG 81 and EMG 85: a pair of popular active pickups
EMG 81 and EMG 85: a pair of popular active pickups

Pickups can be either active or passive. Pickups, apart from optical types, are inherently passive transducers. "Passive" pickups are usually wire-wound around a magnet, and are the most common type used. They can generate electric potential without need for external power, though their output is relatively low, and the harmonic content of output depends greatly on the winding.

Seymour Duncan AHB-1 Blackouts

"Active" pickups incorporate electronic circuitry to modify the signal. Active circuits are able to filter, attenuate or boost the signal from the pickup. The main disadvantage of an active system is requirement of a battery power source to operate the

preamp circuitry. Batteries limit circuit design and functionality, in addition to being inconvenient to the musician. The circuitry may be as simple as a single transistor, or up to several operational amplifiers configured as active filters, active EQ
and other sound-shaping features. The op amps used must be of a low-power design to optimize battery life, a design restriction that limits the dynamic range of the circuit. The active circuitry may contain audio filters, which reduce the dynamic range and mildly distort certain ranges. High-output active pickup systems also have an effect on an amplifier's input circuit.

Stereo and multiple pickups with individual outputs

Rickenbacker was the first manufacturer to market stereo instruments (guitars and basses). Their proprietary "Ric-O-Sound" circuitry has two separate output jacks, allowing the musician to send each pickup to its own audio chain (effects device, amplifier, mix console input).

Teisco produced a guitar with a stereo option. [20] Teisco divided the two sections in the upper three strings and the lower three strings for each individual output.

The Gittler guitar was a limited production guitar with six pickups, one for each string.

Gibson created the HD.6X Pro guitar that captures a separate signal for each individual string and sends them to an onboard analog/digital converter, then out of the guitar via

Ethernet cable
.

See also

Notes

  1. ^ "Invention: Electric Guitar". www.invention.si.edu. Lemelson Center for the Study of Invention and Innovation. Archived from the original on 24 August 2018. Retrieved 21 July 2018.
  2. ^ Lawing, A Scott (14 February 2017). "How Does a Pickup Really Work?". Lawing Musical Products. Dr A. Scott Lawing. Retrieved 2 January 2019.
  3. ^ "Guitar Pickup - MagLab". nationalmaglab.org. Retrieved 2 January 2019.
  4. ^ Elliott, Rod (2021). "Guitar & Bass Pickup Output Voltages". sound-au.com. Archived from the original on 2023-06-01. Retrieved 2024-03-08.
  5. ^ Veallpublished, Dan (2020-12-21). "Bass guitar pickups explained". guitarworld. Retrieved 2023-09-17.
  6. .
  7. ^ "The Structure of the Electric Guitar:[Experiment]Let's make and then test several coils - Musical Instrument Guide - Yamaha Corporation". www.yamaha.com. Retrieved 2023-02-23.
  8. ^ Wheeler. p.214
  9. ^ a b humbucker
  10. ^ Tillman, Donald (2002).
  11. ^ "Gibson Pickups: A Guide to These Epic Game Changers".
  12. ^ Discrete FET Guitar Preamp
  13. ^ Mottola, R.M. (2003). "A Listening Evaluation of Discrete vs Integrated Circuit Audio Preamplifiers in Stringed Musical Instruments". Journal of Musical Instrument Technology (23).
  14. ^ B-Band electret pickup
  15. ^ Schertler Bluestick
  16. ^ "About the amplification of acoustic stringed instruments - VERWEIJ Snaarinstrumenten". Archived from the original on 2014-10-31. Retrieved 2013-01-17.
  17. ^ "LightWave Systems | Technology". Archived from the original on 25 August 2012. Retrieved 13 September 2012.
  18. ^ Wallace, Joe (2006-12-11). "Light Speed Guitars: The Story Of Ron Hoag And His Optical Guitar Pickup". Gearwire. Archived from the original on 2009-05-01. Retrieved 2009-06-09.
  19. ^ "About | LightWave Systems". Retrieved 2012-09-13.
  20. ^ Meyers, Frank. "Teisco's Spectrum—A Rainbow of Switches and Weird Tone Selections". Premier Guitar. Retrieved December 16, 2023.

References

  • Brosnac, Donald (1980). Guitar Electronics: A Workbook. Ojai, CA: d.B. Music Co. .

External links