Long before the electric guitar came along, the hollow-body acoustic guitar made its mark in the music world. An acoustic guitar traditionally does not use amplification aside from the natural sound produced by string vibrations bouncing inside the hollow cavity that makes up the guitar’s body. By employing an open cavity to produce sound, this guitar has the capabilities of a versatile and portable instrument popular among musicians across numerous genres.
An acoustic guitar differs from an electric guitar in its method of sound production, but also in its simplicity: most acoustic guitars do not come with any electronics to produce amplification, though more and more of these guitars are coming stock with pickups that allow the guitar to be played with or without an amplifier. This guitar relies instead on the acoustics of the guitar body, which allows the sound to bounce around inside the hollow cavity and escape through a sound hole beneath the strings.
The process goes something like this: the strings vibrate when struck, creating sound. But since strings only vibrate so much and can create only a small amount of sound, this guitar is designed to allow the strings to vibrate through the bridge of the guitar, and in turn, the soundboard -– or face –- of the guitar. This vibration is then enhanced by the hollow body of the guitar and released through the sound hole. The sound itself is produced naturally and does not rely on any external amplification, though there are pickups available to enhance the sound of the guitar in much the same way electric guitars work.
An acoustic guitar is also notable for its appearance: the most common body style is called a dreadnaught and can feature a cutaway so the player can access frets closest to the body of the guitar. The guitar may also feature different decorations, such as ornate pick guards or rosettes –- decorative inlays -- around the sound hole.
The acoustic guitar must be carefully constructed to create a desirable and unique sound. Guitar builders, also known as luthiers, use a system of braces to create the body itself, and the materials must be chosen carefully for their sound transmission qualities. Luthiers also use their binding materials carefully, choosing certain glues and finishes that will not diminish the overall sound quality of the instrument.
Other elements can affect the sound produced by the acoustic guitar. For instance, the classical guitar uses a similar sound production method but uses nylon strings instead of the more common steel strings, producing a less sharp sound most commonly heard in classical music. Woods, glues, strings, shape of the body, and many other considerations can also affect the tone.