Scale length (string instruments)
The scale length of a string instrument is the maximum vibrating length of the strings that produce sound, and determines the range of tones that string can produce at a given tension. It is also called string length. On instruments in which strings are not "stopped" (typically by frets or the player's fingers) or divided in length (such as in the piano), it is the actual length of string between the nut and the bridge.
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String instruments produce sound through the vibration of their strings. The range of tones these strings can produce is determined by three primary factors: the linear density of the string, that is its mass per unit length (which is determined by its thickness and the density of the material), the tension placed upon it, and the instrument's scale length.