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 LCDs or ones that work on
personal computers. A strobe tuner shows the difference between a reference frequency and the musical note being played. Even the slightest difference between the two shows 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 from either a TRS input jack or a built-in or external microphone connected to the tuner. The first strobe tuner was produced in 1936 by
Conn. It was at first sold as Conn's "Chromatic Stroboscope." then, beginning in the 1940s, as the
Stroboconn. It was manufactured into the 1960s but is mainly a collector piece at present. The front panel 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 temperature-compensated 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. When set at A4 = 440 Hz the tuning fork produced a 55 Hz signal, which drove the four-pole 1650 RPM synchronous motor to which the A disc was mounted. (The other discs were all gear-driven off of this one.) Incoming audio was amplified to feed a long neon tube common to all 12 discs. Wind instrument players and repair people liked this tuner because it needed no adjustment to show different notes; though portable, its total weight was 68 pounds. The best-known brand in strobe tuner technology is Peterson Tuners who in 1967 marketed their first strobe tuner, the
Model 400. Other companies, such as Sonic Research,
TC Electronic, and Planet Waves, sell highly accurate LED-based true strobe tuners. Other LED tuners have a 'strobe mode' that emulates the appearance of a strobe. However, the accuracy of these tuners in strobe mode, while sufficient for most tuning, is no better than in any other mode, as they use the same technique as any basic tuner to measure frequency, only displaying it in a way that imitates a strobe tuner.
Operation 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 110
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 110 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 exactly the same frequency as the spinning of the disc, then the disc appears to be static 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 sometimes changes slightly (a few tenths of a percent) with varying load. Unless reference and measured quantity are interchanged, the operating principle is the same; the 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 of a cent. Advertisements for the Sonic Research LED strobe claim that it is calibrated to ± 0.0017 cents and guaranteed to maintain an accuracy of ± 0.02 cents or of a cent. disc strobe tuner 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" (e.g., notes of short duration), 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 be 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. This is also true of the comb teeth used in mechanical musical instruments like
Music Boxes and the like. In such cases, a technician has to physically remove metal from the tooth to reach the desired note. The metal teeth only resonate briefly when plucked. Great accuracy is required as once the metal is cut or filed away, the lost material cannot be replaced. As such, the strobe-type tuners are the unit of choice for such tasks. Tuners with an accuracy of better than 0.2
cent are required for guitar intonation tuning. One of the most expensive strobe tuners is the Peterson
Strobe Center, which has twelve separate mechanical strobe displays; one for each pitch of the equally tempered octave. This unit (about US$3,500) 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 that is not possible with most other tuning devices. (The TC Electronic Polytune can display the pitch accuracy of up to six pre-selected notes.) It is often used for tuning complex instruments and 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 displays several of the bell's
partials (hum, second partial,
tierce, quint and nominal/naming note) as well as the prime, and each of their partials, on separate displays. The unit is heavy and fragile, and requires a regular maintenance schedule. Each of the twelve displays requires periodic re-calibration. It can be used to teach students about note substructures, which show on the separate strobing displays.
Strobe developments Mechanical disc strobe tuners are expensive, bulky, delicate, and require periodic 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 as accurate as standard mechanical disc strobe tuners. However, there are limitations to the virtual system compared to the disc strobes. Virtual strobes display fewer bands to read note information, and do not pick up harmonic partials like a disc strobe. Rather, each band on a virtual strobe represents octaves of the fundamental. A disc strobe provides "one band correspondence"—each band displays a particular frequency of the note being played. On the virtual strobe system, each band combines a few close frequencies for easier reading on the LCD. This is still extremely accurate for intoning and tuning most instruments—but, as of this writing, no virtual strobe tuner provides detailed information on partials. 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. Both LCD and 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 the maintenance requirements. 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 "StroboSoft". 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 next to the instrument to be tuned. An alternative is the PC-based strobe tuner TB Strobe Tuner with fewer functions. In 2009 Peterson Tuners released a VirtualStrobe tuner as an application add-on for Apple's
iPhone and
iPod Touch. As both mechanical and electronic strobes are still more expensive and arguably more difficult to use in order to achieve the desired results than ordinary tuners, their use is usually limited to those whose business it is accurately to intone and tune
pianos,
harps, and early instruments (such as
harpsichords) on a regular basis:
luthiers, instrument restorers and technicians – and instrument enthusiasts. These tuners make the
intonation process more precise. ==Uses==