Electronic tuner
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An electronic tuner is a device used by musicians to detect and display the pitch of notes played on musical instruments. The simplest tuners indicate whether the pitch of the note played is lower, higher, or approximately equal to the desired pitch. More complex tuners indicate more precisely the difference between offered note and desired pitch. Tuners vary in size from units that can fit in a pocket to table-top models or 19" rack-mount units. The more complex units are used by instrument technicians, piano tuners and luthiers.[citation needed]
The simplest tuners only detect and display the tuning for a single pitch (often "A"),[citation needed] or for a small number of pitches, such as those used in the standard tuning of a guitar. More complex tuners offer chromatic tuning. Some electronic tuners offer additional features, such as adjustable pitch calibration, different tempered scale options, the sounding of a desired pitch through a speaker and read-time settings.
The most accurate tuning devices are strobe tuners, which work in a different way to regular electronic tuners; they are basically stroboscopes. These can be used to tune any instrument, including the initial beating of steelpan drums, bagpipes, accordions, calliopes, bells or any audio device very accurately. They are often 30 times more accurate [clarification needed] than regular LED, LCD or needle display tuners. However, strobe units are generally much more expensive, and the mechanical elements of a mechanical (rather than electronic-display) strobe require periodic servicing. Therefore, these tuners are mainly used by specialists and professional instrument technicians.
Types
Most tuners contain a microphone and/or an input jack (for electric instruments such as electric guitar), circuitry for detecting the pitch, and some type of display (an analog needle, an LCD simulated image of a needle, LED lights, or a spinning translucent disk illuminated by a strobing backlight). Some tuners have an output, or thru-put, so the tuner can be connected 'in-line' from an electric instrument to an amplifier or mixing console, etc. While tuners are usually battery powered, some have a jack for an optional AC power supply.
The waveform generated by a musical instrument is very complex, as it contains a number of partials, and is constantly changing. For this reason the regular tuner must average a number of cycles of the note and use this average to drive its display. Any background noise or harmonics from the musical instrument can easily "confuse" the electronic tuner's attempt to "lock" onto the input frequency. This is why the needle or display on regular electronic tuners tends to waver when a pitch is played. Small movements of the needle, or LED, usually represent a tuning error of 1 cent of a semitone. The typical accuracy of these types of tuners is around +/- 3 cents for quality needle tuners and +/- 9 cents of a semitone for the most inexpensive LED tuners.
Some companies offer one type of tuner (e.g. Behringer, Quick Time and Fender focus on inexpensive tuners), while other companies, such as Boss and Korg, sell a range of standard, pedal, and rack-mountable tuners at varying levels of quality and features.
The "clip-on" tuner clips onto an instrument (commonly at the headstock or bridge) and picks up vibrations, rather than using a microphone or input jack to sense the input frequency. It then displays the pitch of the instrument's vibration on its large LCD display. These types of tuners are reputed to be more accurate than needle, LCD or LED type tuners, but not as accurate as strobe tuners. Clip-on tuners may be more accurate because less interference is picked up in the vibrations of the instrument, allowing the electronic tuner to more accurately 'home in' on the target frequency.[who?]
The "String Master" tuner consists of a regular LED tuner where the electric instrument plugs into the unit's base with a 1/4" TRS cable, or an acoustic instrument via a microphone cable. The unit has a built-in motor which drives a string winder tool at the top to the unit. The unit is then placed over the tuning button of the machine head of the string to be tuned, and a note on the relevant string is played. The unit detects the input note and robotically corrects the pitch to a desired frequency by turning the tuner button to the correct position. It constantly monitors the change in frequency until the "in tune" signal is given.
Some electric guitar tuners are fitted to the instrument itself, such as the Sabine AX3000 and the "NTune" device. The NTune consists of a switching potentiometer, a wiring harness, illuminated plastic display disc, a circuit board and a battery holder. The unit installs in place of an electric guitar's existing volume knob control. The unit functions as a regular volume knob when not in tuner mode. To operate the tuner, the player pulls the volume knob up. The tuner disconnects the guitar's output so the tuning process is not amplified. The lights on the illuminated ring, under the volume knob, indicate which note is being tuned. When the note is brought into tune a green "in tune" indicator light is illuminated. After tuning is complete the volume knob is pushed back down, disconnecting the tuner from the circuit and re-connecting the pickups to the output jack.
Gibson guitars released a model in 2008 called the "Robot Guitar". It is a customized version of either the Les Paul or SG model. The guitar is fitted with a special tailpiece, looking like a regular unit, with in-built sensors that pick up the frequency of the strings. There is a special illuminated control knob with which the player can dial in different tuning options. The headstock is fitted with custom built motorized machine heads that automatically tune the guitar robotically, without need for the musician to manually adjust the machine heads or the guitar's tuning in any way. This system can even assist the player to intonate the guitar when the unit is put into "intonation" mode, displaying how much adjustment the bridge requires with a system of flashing LEDs on the control knob.
Regular needle, LCD and LED display tuners
A needle, LCD or regular LED type tuner uses a microprocessor to measure the average period of the waveform. It uses this to then drive the needle or array of lights. When the musician plays a single note, the tuner senses the input from the microphone or input jack (from an electric instrument). The tuner then displays the input frequency in relation to the desired pitch and indicates whether the pitch of that note is lower, higher, or approximately equal to the desired pitch.
With needle displays, the note is in tune when the needle is in a 90o vertical position, with leftward or rightward deviations indicating that the note is flat or sharp, respectively. Tuners with a needle are often supplied with a backlight, so that the display can be read on a darkened stage.
For block LED or LCD display tuners, markings on the readout drift left if the note is flat and right if the note is sharp from the desired pitch. If the input frequency is matched to the desired pitch frequency the LEDs are steady in the middle and an 'in tune' reading is given.
Some LCD displays mimic needle tuners with a needle graphic that moves in the same way as a genuine needle tuner. Somewhat misleadingly, many LED displays have a 'strobe mode' that mimics strobe tuners by scrolling the flashing of the LEDs cyclically to simulate the display of a true strobe. However, these are all just display options. The way a regular tuner 'hears' and compares the input note to a desired pitch is exactly the same, with no change in accuracy. For more on how strobe tuners work see the dedicated section.
The least expensive models only detect and display a small number of pitches, often those pitches that are required to tune a given instrument (e.g., E, A, D, G, B, E of standard guitar tuning). While this type of tuner is useful for bands that only use stringed instruments such as guitar and electric bass, it is not that useful for tuning brass or woodwind instruments. Tuners at the next price point offer "chromatic tuning", which means that the device will detect and assess all of the pitches in the chromatic scale (e.g., C, C#, D, D#, etc.). Chromatic tuners can thus be used for Bb and Eb brass instruments such as saxophones and horns.
Many models have circuitry that automatically detects which pitch is being played, and then compares it against the correct pitch. Less expensive models require the musician to specify the target pitch via a switch or slider. Most low- and mid-priced electronic tuners only allow tuning to an equal temperament scale.
Electric guitar and electric bass players who perform concerts may use electronic tuners which are built into an effects pedal often called a "stomp box". These tuners have a rugged metal or heavy-duty plastic housing and a foot-operated switch to toggle between the tuner and a bypass mode. Professional guitarists may use a more expensive version of the LED tuner which is mounted in a rack-mount case, and has a larger range of LEDs, thus allowing a more accurate display of the flatness or sharpness. More expensive models allow the user to select reference pitches other than A440.
In some cases, this is used to select a different note, as in the case of bands which detune their guitars to "Eb" or "D" for a lower, more resonant sound. More subtle changes of a quarter tone or less can be made with some models. This enables instrumentalists to tune to a fixed pitch instrument such as an organ or piano that is not tuned to A440. Some Baroque musicians playing period instruments perform at lower reference pitches such as A435. Some higher-priced electronic tuners allow tuning to a range of different temperaments, which is a feature of interest to some guitarists and to harpsichord players.
Some expensive tuners also include an on-board speaker and amplifier which can sound notes, either to facilitate tuning "by ear" or to act as a pitch reference point for intonation practice, while scales or arpeggios are being practiced. Another feature offered on the most expensive tuners is an adjustable "read time", which determines whether the circuitry will attempt to make a quick assessment of the pitch, or make its assessment over a longer period.
Due to their combination of all the above mentioned features, very high-quality needle tuners are suitable for tuning the different types of instruments in an orchestra; these are sometimes called "orchestral tuners".
Strobe tuners
Strobe tuners (the popular term for stroboscopic tuners) are the most accurate type of tuner. There are three types of strobe tuners: The mechanical rotating disk strobe tuner, an LED array strobe in place of the rotating disk, and "virtual strobe" tuners with LCD displays or ones that work on personal computers. A strobe tuner shows the difference between a reference frequency and the musical note. Even the slightest difference between the two will show up as a rotating motion in the strobe display. The accuracy of the tuner is only limited by the internal frequency generator. The strobe tuner detects the pitch either from an TRS input jack or a built-in or external microphone connected to the tuner.
The first strobe tuner dates back to 1936 and was originally made by the Conn company; it was called the Stroboconn. However, these strobes are now mainly collector pieces. They had 12 strobe discs, driven by one motor. The gearing between discs was a very close approximation to the [12th root of two] ratio. This tuner had an electrically-driven tuning fork; the electrical output of this fork was amplified to run the motor. The fork had sliding weights, an adjustment knob, and a dial to show the position of the weights. These weights permitted setting it to different reference frequencies (such as A4 = 435 Hz), although over a relatively narrow range, perhaps a whole tone. Incoming audio was amplified to feed a long neon tube common to all 12 discs. Wind instrument repair people liked this tuner because it needed no adjustment to show different notes.
The best known brand in strobe tuner technology is Peterson Tuners who in 1968 marketed their first strobe tuner, the "Model 400". Other companies, such as Sonic Research and Planet Waves, sell affordable LED-based true strobing tuners. There are other tuners with LEDs that have a 'strobe mode' which simulates the appearance of a strobe. However, the accuracy of these tuners when used in strobe mode is no better than when in any other mode, as it uses the same technique as a needle tuner to measure the frequency of the note, and then it sets the speed of the pattern in the LEDs instead of driving a needle.
Mechanical strobe tuners have a series of lamps or LEDs powered by amplified audio from the instrument; they flash (or strobe) at the same frequency as the input signal. For instance an 'A' played on a guitar's 6th string at the 5th fret has the frequency of 155 Hz when in tune. An 'A' played on the 1st string at the 5th fret vibrates at 440 Hz. As such, the lamps would flash either 155 or 440 times per second in the above examples. In front of these flashing lights is a motor-driven, translucent printed disc with rings of alternating transparent and opaque sectors.
This disc rotates at a fixed specific speed, set by the user. Each disc rotation speed is set to a particular frequency of the desired note. If the note being played (and making the lamps behind the disc flash) is at the exact same frequency as the spinning of the disc, then the disc appears to be static (due to an optical illusion) from the strobing effect. If the note is out of tune then the pattern appears to be moving as the light flashing and the disc rotation are out of sync from each other. The more out of tune the played note is, the faster the pattern seems to be moving, although in reality it always spins at the same speed for a given note.
Many good turntables for vinyl disc records have stroboscopic patterns lit by the incoming AC power (mains). The power frequency, either 50 or 60 Hz, serves as the reference, although commercial power frequency is sometimes shifted slightly to meet load demand. The operating principle is the same; although turntable speed is adjusted to stop drifting of the pattern.
As the disc has multiple bands, each with different spacings, each band can be read for different partials within one note. As such, extremely fine tuning can be obtained, because the user can tune to a particular partial within a given note. This is impossible on regular needle, LCD or LED tuners. The strobe system is about 30 times more accurate than a quality electronic tuner, being accurate to 1/10 of 1 semitone. Advertisements for the Sonic Research LED strobe claim that it is accurate to 0.0017 of one semitone.
Strobe units can often be calibrated for many tunings and preset temperaments and allow for custom temperament programming, stretched tuning, "sweetened" temperament tunings and Buzz Feiten tuning modifications. Due to their accuracy and ability to display partials even on instruments with a very short 'voice', strobe tuners can perform tuning tasks that would be very difficult, if not impossible, for needle type tuners. For instance, needle/LED display type tuners cannot track the signal to identify a tone of the Caribbean steelpan (often nicknamed the "steeldrum") due to its very short 'voice'. A tuner needs to able to detect the first few partials for tuning such an instrument, which means that only a strobe tuner can be used for steelpan tuning.
One of the most expensive strobe tuners is the Peterson "Strobe Center", which has twelve separate mechanical strobe displays; one for each note in the chromatic scale. This unit (retailing at about $3,500 US) can tune multiple notes of a sound or chord, displaying each note's overtone sub-structure simultaneously. This gives an overall picture of tuning within a sound, note or chord, which is not possible with any other tuning device. It is often used for tuning complex instruments/sound sources or difficult-to-tune instruments where the technician requires a very accurate and complete aural picture of an instrument's output. For instance, when tuning musical bells, this model will display several of the bell's partials (hum, tierce and quint) as well as the prime, and each of their partials, on separate displays. The unit is heavy and fragile, and it requires a regular maintenance schedule. Each of the twelve displays require re-calibration over time, dependent on how much it is used. It can be used to teach students about note substructures, which are displayed on the separate strobing displays.
Strobe Developments
Mechanical disc strobe tuners are expensive, bulky, delicate and require periodical maintenance (keeping the motor that spins the disc at the correct speed, replacing the strobing LED backlight, etc.). For many a mechanical strobe tuner is simply not practical for one or all of the above reasons. To address these issues, in 2001 Peterson tuners added a line of non-mechanical electronic strobe tuners that have LCD dot-matrix displays mimicking a mechanical strobe disc display, giving a stroboscopic effect. In 2004 Peterson made a model of LCD strobe in a sturdy floor based "stomp box" for live on-stage use.
Virtual strobe tuners are just as accurate as standard mechanical disc strobe tuners. However, there are limitations to the virtual system compared to the disc strobes. The first thing of note is that the virtual strobes display fewer bands to read note information. A virtual strobe doesn't pick up harmonic partials like a disc strobe, rather each band represents octaves of the fundamental being played. On a disc strobe there's 'one band correspondence' where each band displays a particular frequency of the note being played. On the virtual strobe system each band has a few close frequencies combined for ease of reading from an LCD display. This is still accurate for tuning and intonating most instruments, but for instruments where more information on partials is required, like idiophones and others, there is not a clear separation of the partials that a disc tuner gives.
Sonic Research and Planet Waves both released a true-strobe with a bank of LEDs arranged in a circle that gives a strobing effect based upon the frequency of the input note. These units are also far cheaper than a mechanical device. Both LCD & LED display true strobes do not require mechanical servicing and are much cheaper than the mechanical types. As such, they are a popular option for musicians who want the accuracy of a strobe without the high cost and maintenance schedule. However, LED strobe displays offer no information about the harmonic structure of a note, unlike LCD types which do offer four bands of consolidated information.
Peterson released a PC-based virtual strobe tuner in 2008 called "Strobo Soft". This computer software package has all the features of a virtual strobe, such as user-programmable temperaments and tunings. To use this tuner, a musician must have a computer in the same location that they wish to tune an instrument.
As both mechanical and electronic strobes are still much more expensive (up to about $3,500 US) than regular tuners (around $10-$100) their use is usually limited to people who tune pianos, harps, and early instruments (e.g., harpsichords) or accurately intonate instruments on a regular basis, such as luthiers, instrument restorers and technicians. These tuners make the intonation process more precise, which is important for the correct set-up of an instrument.
See also
External links
- Accessory Fetish A Complete List of Electronic Tuner Manufacturers
- Boss tuners
- Korg tuners
- OnBoard Research Intellitouch tuners
- Planet Waves tuners
- Sonic Research A company offering an LED true strobe tuner
- Peterson tuners
- NTune tuners The NTune device is mounted to an electric guitar's volume control
- Robotic tuner
- Auto-tuning "Robot Guitar"
- An online guitar reference tuner
- An expensive retrofit system for auto-tuning guitars
- Buzz Feiten tuning system home page