The Acoustic Guitar

An acoustic guitar is a guitar that uses only acoustic methods to project the sound produced by its strings. The reason this distinction is made is to differentiate them from electric guitars which use electronic methods to amplify and output the sound.

All guitars produce sound through string vibration. But strings can only displace a small amount of air, so the volume of the sound has to be increased to be heard. Acoustic guitars accomplish this using a soundboard and a sound box. The vibtration of the strings drives the soundboard through the bridge, making it vibrate. Since the body of the guitar is hollow and the soundboard has a larger surface area, this displaces a larger volume of air. The end result is a much louder sound than the strings alone.

The shape of the guitar and the shape of the sound holes will make a dramatic difference in the tones produced. The shape of the guitar affects the way sounds bounce off the inner walls of the sound box and are reflected out to the ear of the listener. As the sound waves bounce within the cavity, some frequencies are amplified while others are muted. This is why guitars of different shapes may produce very distinct sounds. The tonal ranges of different guitars may vary widely. Also, some acoustic guitars have the standard round sound hole while others may have sound holes resembling violins. This will also result in differences in tonal quality.