Guitars come in a variety of shapes, sizes, and types, but there are certain things they all have in common. A guitar has three basic parts: a body, a neck, and the headstock (also referred to as a tuning head). You can learn how to maintain your instrument by understanding the various components better.

Body

There are basically two types of guitar bodies: hollow body and solid body. The hollow body of an acoustic guitar (shown in FIGURE 2-1) is what produces the instrument's sound. The body of the acoustic guitar is composed of the top, sides, and back. The top, or “face,” of the instrument lies just below the strings. The sound hole is the round hole in the center of the top, from which the sound of the instrument emanates. The sides are the narrow pieces between the front and the back, which is the large surface parallel to the top. Generally, the back and sides of the instrument are made out of the same kind of wood, while on the majority of instruments the top is a finer, thinner piece of wood (or laminate, in the case of less expensive guitars). The top is the part of the guitar that most defines the overall sound of the guitar.

Some acoustic guitars have a piece of plastic called a pick guard glued to the top just below the sound hole. Just as the name implies, the pick guard is designed to protect the top of the instrument from damage you might inflict with your pick.

In a purely electric guitar (shown in FIGURE 2-2 on page 21), the body is made of a solid piece of wood to avoid feedback, the screeching that results from resonance when the sound of a guitar is amplified. Below are some commonly used woods in electric guitars:

• Maple: Curly, flamed, and bird's-eye are various types of maple wood used in guitars. This is a bright-sounding wood.

• Mahogany: This hardwood provides a warmer, rounder tone than maple. It is usually found in Gibson Les Paul guitars.

• Alder: This wood is most commonly found in guitars with an overall sonic balance. It is usually favored by players with a broad range of playing styles.

• Swamp ash: This is a lightweight American wood with a bright and distinct tone.

A solid-body electric also houses the electronic pickups (which convert the motion of the strings into an electronic signal that can be sent through an amplifier of some kind), and volume and tone controls (which vary the loudness and bass and treble frequencies of the signal). There is also a socket called an output jack, into which you insert a special plug or jack. The other end of the jack goes into a corresponding socket in an amplifier.

In addition, the body has a bridge, made from either wood or metal, which anchors the strings. There are also strap pins or posts, which you can use to attach a shoulder strap.

Neck

The neck is usually fixed to the body with bolts or glue, though it might also be formed along with the body in one piece. It often has a metal truss rod running through it to strengthen it and help adjust for any slight warping or twisting. The neck is faced with a flat piece of wood (usually mahogany or ebony) called the fingerboard or fretboard. The fingerboard is divided into sections called frets. These sections are marked off by pieces of wire set into the wood, called fretwire. By stopping a string in between the fretwires — that is, “in the middle of the fret” — you determine the different pitches or notes you can make on each string. The strings run from the bridge, along the neck, and across the nut — a piece of wood, plastic, or metal at the top of the neck with slight grooves for each of the six strings — to the tuning pegs.

How does an acoustic guitar work?

When a guitar string is plucked, it produces vibration. This vibration is transmitted through the bridge into the body of the instrument, causing the inside of the body to resonate, which in turn causes the front and the back of the body to vibrate. Compressed waves of sound are then created inside the body and projected out of the sound hole.

The neck of a guitar also provides a primary “tonal color” for the sound of the instrument. Different types of wood give the guitar a distinctive sound. Maple, which is a hard wood, produces a bright, clear sound. Mahogany, which is softer than maple, produces a warmer sound. Another component of the guitar neck is the different types of neck joints. Most guitars have a bolt-on neck. Screws connect the neck to the body — usually found in Fender Stratocasters or Telecasters. A neck-through design means that the neck continues all the way from the headstock to the strap pin at the bottom of the instrument. In this design, the body is actually made up of small wings that are glued to both sides of the neck. A set-in neck glues the neck and body together. This design is usually found in Gibson Les Paul guitars.

Headstock

The headstock holds the tuning pegs (also called tuning machines, machine heads, or tuning gears) that the strings are attached to. In a six-string guitar there are six tuning pegs. Each tuning peg has a knob you can turn with your fingers. The knob tightens or loosens the string tension and thus puts each string into “tune.” A headstock that is flat (FIGURE 2-3) or tilts back (FIGURE 2-4) determines the effect on tone. Flat headstocks are the continuation of the guitar neck. Tilt-back headstocks are broken up into two types: integral and spliced. The integral tilt-back headstock design uses one large piece of continuous wood. A spliced headstock consists of a separate piece of wood glued on to the end of the neck.

Headstocks may have their tuning arranged with three tuning pegs on each side (like a Gibson Les Paul), or with six in-line pegs (like a Fender Stratocaster).