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Precision Strobe Tuners
PST-4 Information

An Electronic Musical Instrument Strobe Tuner for Musicians and Technicians


sharp The Precision Strobe Tuner is a musical instrument tuning aid for technicians and musicians. It combines the principle of the mechanical strobe tuner with solid state electronics, providing a tuning aid which is highly accurate, compact, and easy to use. The difference in pitch between the selected note and the input tone is displayed as the rotation of a two group "pinwheel" pattern of lit LEDs opposite each other around the Strobe Display. Users of mechanical type strobe tuners will find this very familiar. The display is generated by linearly modulating the LED intensity with the rectified input signal waveform, while electronically rotating the circular array. This method used with a high density LED array provides display texture not obtainable using techniques which enable the LEDs digitally to generate a strobe effect. The PST-4 is a true strobe tuner.

It works like this: When a tone is applied to the device, a two group "pinwheel" pattern is produced, with the direction of rotation indicating whether the input tone is sharp or flat, and the rotation speed indicating the degree. The Strobe Display response to pitch changes is instantaneous. When the rotation is stopped and the groups stand still, the instrument is perfectly adjusted. The tuner setting and operation modes are easily configured through the user interface. The Strobe Display provides response speed, accuracy and repeatability far exceeding needle tuning indicators. The Strobe Display also provides information about tone quality and harmonic content through display texture. The user selectable filters provide a high level of flexibility for many tuning tasks. Temperament accuracy is better than .01 cent.

The Precision Strobe Tuner is an invaluable aid to the instrument technician requiring fast response, accuracy and portability. Using the PST-4 filter functions produces a crisp display even from harmonically rich sources. The band pass filter mode can also be used to make measurements of individual tone partials, so the inharmonicity of ringing strings can be characterized.

The Precision Strobe Tuner is also useful to the musician for both general tuning procedures and musical training. In Automatic mode, the PST-4 tracks the input note making many operations hands free. This mode is useful in band instrument intonation training. The student slowly plays a scale attempting to stop the rotation of each note, while the PST-4 provides visual feedback for intonation and ear training.

Digital Signal Processing technology is used in the PST-4 to optimize filtering and dynamic range control to improve the strobe display quality. The lowest notes on a piano tend to be problematic for strobe tuners because of the low fundamental level compared with the partials. This leads to a poor strobe display of the fundamental during the note attack, and a fuzzy pulsing display through the note decay. The optimized filtering and dynamic range control of the PST-3 provides a clear tuning indication of the fundamental of the lowest piano notes right from the note attack.

Using the Band Pass filter modes, it is possible to measure the inharmonicity of individual string partials. Using this capability, one can make the measurements necessary to construct a stretch curve for a given piano. This can be done manually, or the built in Stretch Curve Function can be used to construct a stretch curve from a series of inharmonicity measurements.

A Programable Temperament feature is provided in the PST-4. This feature provides a user programmable temperament mode in which the tuner automatically sets the temperament, or offset, of each note to values preset by the user. This is useful for piano tuning, and can be used to setup the tuner for tuning scales other than the equal tempered. This feature is also useful for setting up and tuning guitars using the Feiten System. The PST-3 provides 40 banks of user programmable temperament each with 88 notes.

U.S. Patent 5777248.

More PST-4 Info:

PST-4 Operation Manual and Specs
Video Demos
Application Information
User Comments

What's New in The PST-4?

The PST-4 is an updated version of the PST-3 with additional features and performance improvements. The PST-4 can be operated from either an external wall transformer or internal batteries (6 AA cells). A NiMH battery charger has been added. Digital Signal Processing (DSP) technology is used in the PST-4 to optimize filtering and dynamic range control to improve the strobe display quality, and to improve automatic note detection functions. The tuning indicator arc has been added across the top of the Strobe Display ring. This display acts as a needle indicator, and is used to course tune the instrument. The PST-4 now has 40 banks of programable temperament. A built in function for constructing the stretch curve for a given piano has also been added.

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