All musical instruments, especially multi-stringed ones such as the piano and harpsichord, require periodic tuning to insure that they consistently reproduce the proper pitches when played.
At present this periodic tuning is accomplished primarily by listening for the beat signal between the note and an audible reference frequency. This is inherently an inaccurate method, and in the case of multi-stringed instruments such as pianos and harpsichords it requires skill far beyond that of the average musician.
There exist today two types of electronic aids which enable the person of no special skill to successfully tune a multi-stringed instrument. In the first of these aids the audible note from the instrument is converted into pulsations of light which are used to illuminate a rotating strobe disc. Deviation of the frequency of the note from the proper value is displayed as apparent movement of a pattern of light and dark spots on the disc.
The second method employs an electronic frequency counter to measure the frequency of the note and provide a digital display of the frequency in hertz. The user must then compare this frequency to the desired frequency and adjust the instrument accordingly.
Both these methods suffer from inherent disadvantages which have prevented their widespread use. The strobe disc method employs an electric motor and is therefore bulky as well as being relatively inaccurate. The frequency counter method has a slow response time, limiting its usefulness to the middle and upper octaves, in addition to which the digital readout is difficult for an untrained person to interpret.
The invention herein described seeks to overcome these disadvantages, thus making it possible for an untrained person to quickly tune any note in the musical spectrum with an accuracy exceeding that of the best professional ear.