Introduction to Tuning
In musical terms, to tune is to correct musical pitch. There are many possible causes for any instrument to go out of tune (or have incorrect pitch). Regardless of the method the instrument became out of tune, the results are all the same—the sound produced by the instrument is not pleasant to the ear. The common solution musicians use to solve this problem is to tune there instrument before they use it. There exist a variety of methods of tuning an instrument. Some musicians have the ability to identify a certain pitch, allowing them to tune an instrument with no additional information besides the out of tune note played by their instrument. For those less fortunate or less trained musicians who do not possess this ability, a common method of tuning is to hear a correct (in tune) pitch and then attempt to match this pitch with their own instrument. This method of tuning is also useful to synchronize the tuning of many instruments. An example of this can be heard at the beginning of classical orchestra concerts. There is one issues with this method of tuning—the musician tuning his or her instrument must have access to a correctly tuned instrument to compare pitches. Often an in-tune instrument is not available. This is a problem our project attempts to solve. There are existing devices and apps which are used to tune instruments. Our project differentiates itself by playing back the sound (all the musical qualities) of the instrument being tuned.
Before the structure of a musical instrument is described, the terminology used to describe it must be defined. The most important terms to understand are defined below.
-
Fundamental: Also referred to as fundamental frequency, is the lowest frequency which is perceived in a musical note
-
Partial: An individual sign wave which is part of a complex note
-
Harmonic: Any integer multiple of the fundamental frequency
-
Pitch: The fundamental frequency of the musical note
In the case of many instruments (guitars, pianos, organs, etc.), the partials are aligned with the harmonics. Because of this alignment, the two terms are often used interchangeably.
Often it is the case, that the fundamental frequency is the highest in amplitude. In general, as frequency increases the magnitude of the harmonics decrease. The rate and manner of this depends on may factor such as: the instrument being played, the way the node was played (hard/soft, plucked/bowed), the specific note being played, and even down to the temperature of the instrument. Partials aligning with the ideal harmonic positions are higher in magnitude than those between harmonics. However, the low amplitude partials between harmonics are often what gives an instruments its particular sound (or timbre).