The acoustic guitar is found all over the globe and this cultural adoption and historical evolution has led to many variations in design and purpose. The ukulele, which was based on the four-stringed braginho or cavaquinhos from Portugal is an example of an earlier small-sized European guitar being introduced to a different society; the word ukulele is Hawaiian for ÒfleaÓ. There are two kinds of acoustic guitar: steel-string and classical. Classical guitars have a wider neck and use nylon strings. Steel-strings have a defined and sharp sound that is a distinctive component of a wide range of popular music styles; country and rock are two examples. The nylon strings of the classical guitar allows the guitarist to play complicated arrangements and barres with ease. Both types of guitar can be played using a plectrum (pick) or finger-style. The steel-string acoustic is sometimes referred to as a flat top. The word top refers to the face or front of the guitar. The front is also sometimes called the table.
The body of any acoustic is large and hollow; acting as a resonating chamber which amplifies the strings. A simple proof would be to strike an open string and as the note is sounding lightly place a finger on the table of the guitar. You should feel the wood gently vibrating to the struck note. Larger bodied guitars with bigger curves tend to have a deeper or heavier tone, while guitars with a smaller body tend to sound brighter. Acoustic guitars sometimes have cutaways, similar to the cutaway on the Gibson Les Paul shown in the picture below, which allows greater access to the higher frets. This also changes the tone. Acoustic guitars have a weaker sustain than electric guitars but master-built classical or steel-string guitars often feature very good sustain and excellent overall performance. There are many entry-level acoustic guitar models that are manufactured to a high standard that are entirely suitable as a first guitar for beginners. If you wish to buy something more expensive then it is important that the front should be made from a single piece of wood (not ply) and closely grained.
The timbre (pronounced tam - bre) of the acoustic guitar lends itself to a variety of tasks and roles. It's a songwriter's tool because of its portability and ease of use and its gentle harp-like arpeggios and rhythmic chordal strumming has always found favour in an ensemble setting. When the performance is in a personal setting or amphitheater, the acoustic guitar can be heard with no additional amplification because the resonating chamber of the guitar itself creates acoustic amplification. In some situations the acoustic guitar is not loud enough to be heard by all the people in an audience and amplification is required. An acoustic guitar can be amplified by placing a microphone several inches from the sound hole or by installing a pickup designed for acoustic guitars. The need for guitars that retain their acoustic qualities when plugged into an amp or PA has led to the invention of the electro-acoustic guitar.
The electric guitar is the workhorse of rock music and is also used extensively in blues, jazz and pop music. Electric guitars need to be plugged into an amplifier to be heard adequately. They are usually solid-body guitars but archtop electric guitars with hollow bodies are available which gives them some acoustic resonance (see below). The timbre of the electric guitar is not comparable to the timbre of an acoustic guitar. The pickups are vital to the sound of the guitar. The pickups and amplifier used with a solid-body electric guitar creates a sound that is metallic with a lengthy decay (sustain).
The design of the electric guitar is not determined by the need for the deep resonating body that acoustic guitars must possess and this had led to the development of contoured and thin electric guitars which can be more comfortable to hold and play. The design variations amongst electric guitars allows them to produce a wide variety of tones. The two most popular basic shapes of the electric guitar are the Fender Stratocaster design and the Gibson Les Paul design. The strings of an electric guitar are thinner than the strings of an acoustic and closer to the neck; therefore less force is needed to press them down. The electric guitar is capable of producing sounds and effects that would be difficult on an acoustic. The ease of bending strings sometimes used in combination with a whammy bar has created some of the greatest modern guitar solos. Fret-tapping is an electric guitar technique that has led to a different way of using the fretboard; allowing chords and melody lines to be played that would have been impossible using the standard technique of strumming and fingerpicking.
The choice of amplifier is fundamental to the sound created and should be regarded as the second half of the guitar. See the Buying an Amplifier section for details. Seven-string electric guitars have a string above the low E string which is tuned to a B and lower in pitch than the low E. They are popular with guitarists who play metal music.
An archtop is a hollow or semi-hollow acoustic or electric guitar which uses steel strings. The arched top creates a unique timbre and other elements taken from the design of the mandolin or violin also add to the distinctive tone of the archtop guitar. The body of the archtop guitar, whether hollow or semi-hollow, has a sound block in the middle and they also have violin f-holes cut into the table.
Archtop guitars may be acoustic or electric and can look very similar with the only distinguishing feature being an electromagnetic pickup. One problem with archtop hollow-bodied guitars is that when played through an amplifier they tend to generate feedback. The semi-hollow archtop was developed to make feedback less of an issue. Archtop guitars have been particularly popular in jazz music because their thicker strings add tone.
Some solid-body electric guitars have an arched top body shape but the name archtop is usually reserved for the hollow and semi-hollow guitar.
The double-neck guitar is basically two different kinds of guitar sharing one body. This design allows the guitarist to easily access and switch between either neck. Made famous by Jimmy Page, the double neck guitar typically will have a standard six-string neck and a twelve-string neck. Other combinations exist, such as a six-string and bass or a six-string with frets and its fretless version.
Steve Vai has been known to play a triple-neck guitar. The double-neck guitar came about in the 1970s because of the changes in recording technology. The recording technology of the 1960s relied on only 4 tracks and multi-layered guitar parts, though possible, were not frequently used. The bands of the 1960s would usually have two guitarists and this achieved the desired affect. The invention of 8 track recording meant more freedom to create complex guitar parts. The guitarist could lay down the rhythm track using a twelve-string guitar and then record onto a separate track, the lead break using a six-string guitar. This left the problem of how a single guitarist could perform these parts live without stopping to change guitars and the double-neck guitar provided the solution.