An electronic tuner is a device used by musicians to detect and display the pitch of notes played on instruments such as fretted stringed instruments, unfretted stringed instruments, woodwinds, brass, timpanis, harpsichords, and clavichords. Tuners indicate whether the pitch of that note played is lower, higher, or approximately equal to the desired pitch. They vary in size from units that can fit in a pocket to table-top models or 19" rack-mount units.

Depending on the type, tuners range in price from $10-$100 US for standard needle, LCD or LED electronic tuners. Electronic and mechanical strobe tuners vary from $200-$3,500 US where the most expensive units are used by instrument technicians, piano tuners and luthiers.

The least expensive tuners only detect and display the tuning for a single pitch (often "A"), or for a small number of pitches. More expensive tuners offer "chromatic tuning", which is more useful for Bb and Eb brass instruments, such as saxophones and horns. Companies such as Boss, Korg, and Fender sell a range of standard, pedal, and 19" rack-mounted tuners. Some higher-priced electronic tuners offer additional features, such as adjustable pitch calibration, different tempered scale options, the sounding of a desired pitch through a speaker & read-time settings.

The most accurate tuning devices are strobe tuners, which work in a different way to regular electronic tuners. 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 more than 30 times more accurate than regular LED, LCD or needle display tuners. The most common brand of strobe tuners is Peterson. However, these units are generally much more expensive, and the mechanical elements of a mechanical strobe (opposed to electronic-display strobes) require periodical servicing. Therefore, these tuners are mainly used by specialists and professional instrument technicians.

Design and functioning

The waveform generated by a musical instrument is very complex, as it contains a number of overtones, 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 represents 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 style developed by the IntelliTouch brand clips onto the 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 insturment's vibration on it's 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.

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 entire unit is then placed over the tuning buttons of the machine head, and a note on the relevent string is played. The unit detects the input note and automatically 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 permanantly fitted to the instrument itself. The NTune device is one such example. This device consists of a switching potentiometer, a wiring harness, illuminated plastic display disc, a circuit board, and a battery holder. The unit installs under an electric guitar's existing volume knob. To operate the player pulls up the volume knob to tune. As the LED tuning ring has bypass circuitry, it cuts out the guitar's output so the tuning process is not amplified. 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.

Regular needle, LCD & LED display tuners

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 flasing 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 the tuning for a single pitch (often "A"), or for 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 featuers, 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

The first strobe tuner dates back to 1936 and was originally made by the Conn company. However, these strobes are now mainly collector pieces. The most 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 that 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 frequencey of 155Hz when in tune. An 'A' played on the 1st string at the 5th fret vibrates at 440Hz. 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 metal disc. 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 disc 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 more the disc seems to be moving, although in reality it always spins at the same speed for a given note.

As the metal disc has multiple bands, each with different spacings, each band can be read for different overtones within one note. As such, extremely fine tuning can be obtained, because the user can tune to a particular overtone 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, and "sweetened" tunings. Due to their accuracy and ability to display overtones 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 overtones 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 seperate 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 overtones, 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.

Developments

Sonic Research & 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, LCD 'virtual-strobes' have less 'bands' (usually four at the most) than mechanical disc strobes (which have eight) and therefore they do not relay as much information about the note's overtones as the mechanical versions. LED strobe displays offer no information about the overtone structure of a note.

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 makes the intonation process more precise, which is important for a correct set-up and intonation.

See also

• Microtuner

External links

• Accessory Fetish A Complete List of Electronic Tuner Manufacturers
• Boss tuners
• Korg tuners
• Planet Waves tuners
• Sonic Research A company offering an LED true strobe tuner
• Peterson tuners
• An online guitar reference tuner
• NTune tuners The NTune device is mounted to an electric guitar's volume control