The guitar sound

Have you ever noticed that a piano, a harp, a mandolin, a banjo and a guitar all play the same notes (frequencies) using strings, but they all sound so different? If you hear the different instruments you can easily recognize each one by its sound. For example, anyone can hear the difference between a piano and a banjo!
An acoustic guitar generates its sound in the following way:

1. When the strings on a guitar vibrate, they transmit their vibrations to the saddle.
2. The saddle transmits its vibrations to the soundboard.
3. The soundboard and body amplify the sound.
4. The sound comes out through the sound hole.

The particular shape and material of the sound board, along with the shape of the body and the fact that a guitar uses strings, give a guitar its distinctive "sound."

Sound, Tones, and Notes

The guitar is a musical instrument, so its goal in life is to make music. Music is the arrangement of tones into patterns that the human brain finds pleasing (or if not pleasing, then at least intriguing). In order to better understand music, let's start at the beginning: "What is sound?"
Sound is any change in air pressure that our ears are able to detect and process. For our ears to detect it, a change in pressure has to be strong enough to move the eardrums in our ears. The more strongly the pressure changes, the "louder" we perceive the sound to be.
For our ears to be able to perceive a sound, the sound has to occur in a certain frequency range. For most people, the range of perceivable sounds falls between 20 Hertz (Hz, oscillations per second) and 15,000 Hz. We cannot hear sounds below 20 Hertz or above 15,000 Hertz.
A tone is a sound that repeats at a certain specific frequency.

A tone is made up of one frequency or a very small number of related frequencies. The alternative to a tone is a combination of hundreds or thousands of random frequencies. We refer to these random-combination sounds as noise. When you hear the sound of a river, or the sound of wind rustling through leaves, or the sound of paper tearing or the sound made when you tune your TV to a nonexistent station, you are hearing noise.