Ok so you need some fundaes on how the guitar works...mail me if this is not enough
Before we launch ourselves into a lengthy discussion on the parts of a guitar and so on and so forth let us first understand the basic formulae and terms in acoustics, which will help us understand guitars better...
Tone: is made up of one frequency or a collection of related frequencies which repeat itself at regular intervals.
Noise: A noise is a collection of thousans of frequencies that do not sound very pleasing.
Musical Note : This is a collection of tones. The only difference is that the frequencies in a Musical note are fixed. They are fixed so that the set of frequencies together sound pleasing to the ear.
Now these frequencies are determined by using a fixed set of multiples.
So now you have a frequency say 264 Hz. By subsequently multiplying the numbers by a set of fractions we obtain what we call a MAJOR SCALE.
The set of fractions are
| 9/8 | 10/9 | 16/15 | 9/8 | 10/9 | 9/8 | 16/15 | 9/8 |
So if we multiply 264Hz by the first fraction and the resulting number by the 10/9 and continue the multiplication similarly ...we would obtain the set of frequencies(in Hertz)
264
297
330
352
396
440
495
528
Now these set of frequencies together form the C MAJOR SCALE...
The individual frequencies form individual notes as follows
| C | 264 |
| D | 297 |
| E | 330 |
| F | 352 |
| G | 396 |
| A | 440 |
| B | 495 |
| C | 528 |
So what we have here is the C Major Scale composed of pure notes. In fact when you start learning the guitar the C scale is the first one you play because it lets you identify all the pure notes...
Now one thing to notice is that the last C-note has twice the frequency of the first one,this forms the basis of octaves. You can play a note a octave higher. In the guitar you can play the same note an Octave higher on the 12th fret...(a piano incidentally spans 7 octaves :))
Now we know stuff about pure notes what the heck are Sharps(#) and Flats(b)...
In the earlier example we started the multiplication with the C-note , now suppose we start with the D-note we should logically land up with the D-Major Scale...and we do let us now have a lot at the D major scale , the notes and the frequencies...(we use the same multiplying factors )
| D-Major Scale | Frequency(in hertz) |
| D | 297 |
| E | 334.1 |
| F | 371.3 |
| G | 396 |
| A | 445.5 |
| B | 495 |
| C | 556.9 |
| D | 594 |
Hey let me now compare the C-Major Scale with the D-Major Scale and let me see whether the frequencies for the individual notes match up ...
| Note | C-Major Scale | D-Major Scale |
| A | 440 | 445.5 |
| B | 495 | 495 |
| C | 528 | 556.9 |
| D | 297 | 297 |
| E | 330 | 334.1 |
| F | 352 | 371.3 |
| G | 396 | 396 |
Hmm..we see an approximate match for all Except the F and the C notes ...so we call them Sharp , or symbolically denote them as a "#".
Now we come to an important term called the TEMPERED SCALE. This is a scale with the A-note set at 440 Hz, and the other notes tuned accordingly. In this scale the next note can be obtained by multiplying the previous note by the 12th root of 2...(1.0595)..Hmmmm...needless information...
So much for notes and all ...
When we strike an open note what actually happens in the guitar is as follows.
We are creating transverse waves in the string. These move along the length of the string and are transmitted to the bridge, where they are reflected back forming standing waves. (Constructive interference)! The SoundBoard picks up the frequency of the standing wave,through the bridge. The SoundBoard then transmits it into the Soundbox, which amplifies the sound. Nice ...
All throughout the tension in the string remains the same, it is only the length of the vibrating string that changes.
The velocity of the transverse wave can be given y V=sqrt(TL/M)
T---Tension in the string
M---mass of the string
L---Length of the vibrating part of the string
Once the velocity is known we can calculate the frequency using
f = V/(2*L)
We see that there is a direct correspondence between the frequency and the Tension. This is why as you tighten the Tuning Pins the frequency of the sound produced from the affected string increases.
When tuned the guitar strings have approximately the same tension.The reason they produce different frequencies are because the Mass of each string varies. If we were to plug the Velocity Equation into the one for frequency we would find that the frequency is inversely proportional to the square root of the Mass of the string.Hence base strings emit lower frequencies, because their mass is higher.In the case of steel strings, the string is surrounded by coils of wire, to increase its weight.