The acoustic guitar is one of the most popular musical instruments in the world and it is actually a guitar that uses only acoustic methods to project the sound produced by the vibration of the strings. Because the strings displace a rather small amount of air there is need for amplifiers so that the air can be heard. The amplifiers are the sound board and a resonant cavity, also called the sound box. The body of the acoustic guitars are hollow and the vibrating strings move the sound board through the bridge and move it back and forth with every cycle of the string's vibration. If the sound board weighs less the sound is louder. However, there are limitations to how thin the sound board can be made so that the guitars won’t break.
These musical instruments have braces inside that provide strength and resistance. As the sound board has a large surface area it naturally displaces a bigger volume of air, thus producing louder sounds than the strings alone and its vibrations produce sound waves from both back and front faces. The sound box of these musical instruments provides support for the sound board and also a resonant cavity and reflector for the sound waves that are produced within the back face of the sound board. The acoustic guitars’ back vibrates too (but to a lesser extent) and is also driven by the air in the cavity. In the end, the sound is pushed through a hole into the body (sound hole). At this point, the sound mixes with the sound produced by the front face, resulting in a complex mixture of harmonics that give acoustic guitars their distinctive sound.
One of the most popular styles of these musical instruments is the Dreadnought, which represents a big instrument with a full sound, a lot like a bass guitar. The dreadnought guitars are created to accompany singers and fit into a wide range of musical idioms. If you are an average player, this is definitely the right guitar for you.
12 String Dreadnought – a type of acoustic guitar that has 12 strings, which work in pairs tuned to the same notes. The first and second pairs are tuned to the same pitch and the rest are tuned to the same notes one octave apart. Thus, has a 12 string has a richer timbre, while the notes and chord shapes are the same as the standard six-string. However, the additional string tension makes these musical instruments somewhat less than ideal for beginners.
Cutaway Dreadnought – is another style of dreadnought guitar, which has a cutaway that allows access to the highest register. Not everyone appreciate these types of guitars, but the truth is that anyone who wants to play those frets needs to be able to reach them.
Parlor Style – these acoustic guitars usually have smaller bodies than other types of guitars and this is done in order to provide for a more even frequency response. Generally, the neck of parlor guitars is wider and is most often the choice of finger style players. The wider neck better accommodates this style of player giving him/her more room to get individual fingers between the strings. The mid frequencies of these musical instruments are punchy and pleasing making these guitars a good choice for all, except classical or flamenco players.
Classical Guitar (Nylon String Guitar) - Classical guitars are famous for their use of nylon strings. These musical instruments have a wide neck and a very flat fingerboard. Instructors usually recommend it for beginners as the lighter string tension and greater string gauge are easier on the fingers. Classical guitars are best for classical music, thus if you intend to play more popular musical styles you are advised to stick to the metal strings.
Jumbo Acoustic Guitar - Jumbo guitars are created to be loud almost like a bass guitar. It is very similar in functions to the dreadnaught. Keep in mind that they tend to get lost in the mid frequencies as they are overpowered by the bass.
Some of the most popular musical instruments of the last two centuries are definitely the acoustic guitars, whose potential has been extremely developed with the design of several types and styles.