The term diapason comes from the Latin diapāson, which in turn has its origin in the Greek language. The notion is used in the field of music to name an interval formed by five tones (two minor and three major) and two major semitones (diatessaron and diapente), according to the first meaning mentioned by the dictionary of the Royal Spanish Academy (RAE).
The concept, however, has other more frequent uses even in the same musical context. In string instruments, such as the guitar, violin and bass, the fingerboard is the section of wood that covers the neck and on which the strings are stepped or pressed. When the instrument has frets, they are embedded in the fretboard.
The element that allows instruments and voices to be adjusted in terms of their pitch is also called a tuning fork. The fingerboard is a metal piece, invented by the British John Shore in the eighteenth century, which is shaped like a fork. The vibration of the tuning fork generates a sound that is taken as a reference when tuning an instrument, both one made by humans and the voice. See Abbreviation Finder for acronyms related to tuning fork.
Depending on its material and shape, the tuning fork emits a specific sound (the most common is the note 440, which has a frequency of 440 hertz). As the sine waves produced by the tuning fork always keep the tuning intact, its sound serves as a reference when trying to achieve the tuning of an instrument.
The 440, in fact, has been considered a standard by the International Organization for Standardization for several decades. This makes the frequency of this sound the most frequent for tuning and, therefore, the reference sought on tuning forks.
Using a tuning fork can be as simple as complicated, depending on the goal that the person pursues. First of all, it is necessary to learn to hold it and cause its vibration effectively; then, we must bring it closer to the ear to finally hear the note it produces and use it as a reference point for the tuning of the desired instrument.
It is important to point out that the tuning fork is much more than a simple tuning tool: for the most passionate musicians, it is an inevitable travel companion, which they always carry in their pocket. The tuning fork is often used even by people who have managed to educate their ears to recognize the height of sounds without the need for an external reference (that is, those who have perfect pitch), since its operation is practically infallible and, therefore, it offers a reliability percentage greater than that of our brain.
Let’s look at an example to understand the complexity behind the use of the fretboard. When a guitarist uses it to tune his instrument, he must combine it with a series of musical and technical knowledge that allows him to achieve his goal, since otherwise the reference note is useless.
The Spanish guitar has six strings, which are numbered starting with the bottom end and must be tuned to the following notes: mi, si, sol, re, la and mi. But this is not all, since the height of these notes must correspond to that of certain octaves of the piano: E 4, B 3, G 3, D 3, A 2 and E 2.
To be able to tune the Spanish guitar with the fingerboard, you also have to know the concept of musical intervals, which we can broadly define as the difference between two notes, both in height and frequency, something that is also useful to locate yourself in a certain note with the voice: if we know how to mentally calculate an interval, such as being a major fourth, we can take the A 440 and sing a D natural without problems.