Classical Guitar

An acoustic guitar is one not dependent on an external device to be heard. The acoustic guitar is quieter than other instruments commonly found in bands and orchestras so when playing within such groups it is often externally amplified. Many acoustic guitars available today feature a variety of pickups which enable the player to amplify and modify the raw guitar sound.

There are several notable subcategories within the acoustic guitar group: classical and flamenco guitars; steel string guitars, which include the flat top or "folk" guitar; twelve string guitars and the arch top guitar. The acoustic guitar group also includes unamplified guitars designed to play in different registers such as the acoustic bass guitar which has a similar tuning to that of the electric bass guitar.
Thanks to http://en.wikipedia.org/wiki/Guitar