Solid body guitars are guitars that have no holes for sound or an internal cavity to accommodate vibration. They are usually made of hardwood with a lacquer coating and have six steel strings The sound that you hear from electric guitars produced by pickups on the guitar which convert the string vibrations into an electrical signal. The signal is then fed into an amplifier and speaker. One of the first solid body guitars was invented by Les Paul. The first mass produced solid body guitar was Fender’s Broadcaster first made in 1948, five years after Les Paul made his prototype.

Hollow body guitars have a hollow body and electronic pickups mounted on its body. They work in similar ways to solid bodied guitars except that because hollow body guitars also vibrate, the pickups convert a combination of string and body vibration into an electrical signal.

Semi-hollow body guitars strike a balance between the solid-body and hollow body guitars, with greater resonance and sustain than true solid body guitars, as well as lighter overall weight. Typically, a semi-hollow body guitar will have a form factor more similar to a solid body electric guitar, and may include two sound holes, one, or none. Many guitars otherwise sold as solid bodied instruments are built with “weight relief” holes bored into the body which nonetheless affect the sound of the instrument.

Some steel string acoustic guitars are fitted with pickups purely as an alternative to using a separate microphone. They may also be fitted with a piezzo-electric pickup under the bridge, attached to the bridge mounting plate, or with a low mass microphone inside the body of the guitar that will convert the vibrations in the body into electronic signals, or even combinations of these types of pickups, with an integral mixer. Are called electric-acoustic guitars, and are regarded as acoustic guitars rather than electric guitars because the pickups do not produce a signal directly from the vibration of the strings but rather   from the vibration of the guitar top or body. These should not be confused with hollow body electric guitars, which have pickups of the type found on a solid body electric guitars. Acoustic Electric guitars are also known to guitar players as “Semi-Acoustic” guitars.

There are many guitars that have different quantities of strings. There are one-string, four-string, seven-string, eight-string, nine-string, and twelve-string guitars. One-string guitars are rare, but are sometimes heard, particularly in Delta blues, where improvised folk instruments were popular in the 30’s and 40’s. . The four-string guitar is best known with guitar player Tiny Grimes, who played on 52^nd street with the beboppers and played a major role in Prestige Blues Swingers. Seven-string guitars mostly add a low B- string above the low E. Both electric and classical guitars exist designed for this tuning. Another less common seven-string arrangement is a 2^nd G-string situated beside the standard G- string and tuned an octave higher. Eight-string electric guitars are rare, but not unused. The largest manufacturer of eight-string electric guitars is Warr Guitars. Nine-string electric guitars have two G, B, and high E-strings each, tuned in unison. Twelve-string electric guitars feature six pairs of strings, usually with each pair tuned to the same note. The extra E, A, D, and G-strings add a note on octave above, and the extra B and E-strings are in unison.