Acoustic guitars are similar to electric guitars in many respects, they have a body, neck, fretboard, bridge and tuners. However they generate volume via a sound hole rather than pickups found on an electric guitar. Acoustic guitars also strung with heavier gauge to help generate louder volumes due to the lack of pickups and therefore no amplifier helping to produce volume.
Classical guitars are different to steel string acoustics in a few ways. The low E, A and D are wound metal strings with the G, B and high E string made out of nylon. Classical guitars also have different fretboard scale lengths and radius’ to their steel string counterparts. Classical guitars are also called Spanish guitars and are the instruments used by flamenco guitarists as well as classical musicians.
Both Steel strung and classical acoustic guitars can be fitted with a pickup. Acoustic guitars can have a magnetic pickup which are the same pickup types found on electric guitars. However, the most common pickup on an electro acoustic is called a piezoelectric. The piezo is placed under the bridge inside the guitar. This type of pickup doesn’t work in the same way as magnetic pickups. Rather than use magnets and copper wire the Piezo consists of metal and ceramic parts. Wires are attached to both parts and an electrical signal is created when there are changes in pressure due to the strings being played.
All electro acoustic guitars have a preamp. The preamp amplify’s the electrical signal created by the piezo pickup before it reaches the guitar amplifier. Preamps have tone controls and equalisers giving the guitarist the ability to shape the sound of the guitar. They often also feature a guitar tuner and sometimes effects such as reverb.
Bass guitars are most commonly either 4, 5 string instruments. The 4 string Bass is tuned in the same way as a double bass (low to high) E, A, D, G. These notes are one octave lower than the same notes on a standard guitar, the 6 string guitar also having high B and E strings. The 5 string Bass has an additional string, usually a low B string making the tuning B, E, A, D, G. Other variations of the Bass are the fretless and the 6 string Bass. The tuning for the 6 string Bass is the same as the 5 string with an additional high C string. The Bass guitar provides the low end frequencies in a band and appears in virtually all styles of music.
The ukulele originated in Hawaii and is basically a small 4 string guitar. There are four main kinds of ukulele – soprano, concert, tenor and baritone. The strings are made of nylon and the most common tuning is (low to high) – G C E A.
The 12 string guitar consists of 6 pairs of strings. The low E, A D and G are paired with strings an octave apart. The B and High E string are paired with duplicates of the same string. The picture below shows the standard 12 string tuning. The notes shown in larger fonts are an octave lower than the smaller fonts.
7 and 8 string guitars with are used by classical, Jazz and more frequently progressive metal players. 7 string guitars have an extra low B string, 8 string guitars have the B with the 8th string being an F#. These strings are often lowered to create an even heavier sound. There are even 9 and 10 strings available for guitarists looking for even more tonal range.