The Guitar

Guitar Design

Although there are seemingly infinite variations on guitar design practically all share the same basic components. The function of the neck and strings on acoustic and electric guitars is essentially the same. So, the following description applies to both. However, the body of each type is quite different and separate descriptions are given for each.

The Neck

• Headstock - Beginning from the top of the neck we start with what is called the headstock. The headstock supports the machined tuning screws for adjusting the strings to the proper pitch.

• The Nut - Just below the headstock is the nut, which is inserted between the headstock and the fretboard, and functions as one of the two termination points for the strings. The nut has small grooves that each string sits in, allowing them to stay aligned. On many guitars the nut is made of plastic, but on finer quality guitars it is made of bone, ivory, or high-quality composite materials.

• The fretboard (or fingerboard) - This piece of wood is glued onto the front face of the guitar's neck. The fretboard is usually made of rosewood or maple and has metal strips, called frets, mounted along it's surface. When strings are pressed down on the frets it changes the vibrating length of the string and thus its pitch. On most guitars the first 14 or 15 frets are free of the guitar body, while the remaining can only be accessed on the portion of the fretboard that is on top of the guitar body. Accessing these higher frets is more difficult on acoustic guitars unless there is a "cutaway" in the guitar body. Virtually, all electric guitars employ cutaways. Also set into the fretboard are inlaid fret markers. These come in various shapes and materials, but their function is to assist the player in locating fret numbers quickly. The fret markers are typically placed on the odd numbered frets (3, 5, 7, etc) except for the 12th fret, which usually has two markers.

• Neckjoint (or heel) - This is the assembly that mounts the neck to the guitar body.

• Strings

• Truss-rod

The Body

• Acoustic Body - The acoustic guitar body is the major determinant of sound quality. It consists of a soundboard ( the top), the back, and the sides. All of these parts are made of thin sheets of wood, which are carefully choosen for their acoustic properties and typically called tonewoods. The soundboard is nearly always made of spruce or cedar while the back and side woods vary (mahogany and rosewood being the most common). Inside the guitar body, on the back of the soundboard, a bracing system is used. These braces come in different patterns and affect the sound in different ways, but the main purpose is to strengthen the very thin soundboard. The soundboard also has one or more soundholes cut into it to allow the vibrating air (which is the sound we hear) to escape. Guitar bodies are shaped somewhat like a pear with bulges at the top and the bottom. These bulges are called "bouts" and they heavily influence the tone of the guitar's upper and lower registers.

• Electric Body - The body of an electric guitar and the way it produces sound differs substantially from that of an acoustic guitar. The body of an electric guitar does have some impact on the instrument's acoustic qualities, but it isn't the primary means of producing the sound. Electric bodies are nearly always made from a solid piece of wood, although sometimes other materials are used. Electric guitars use pickups that are mounted in the body and underneath the strings. They are basically transducers that detect, or "pick up", the string vibrations. These vibrations are then transferred into electrical signals by the inner electronics and sent out of the instrument via a cable. The guitar cable is connected to an amplifier and possibly other devices that can modify and alter the signal, such as a distortion pedal. It is the amplifier that receives these signals and then amplifies the sound through a speaker.

Bridge and Saddle

• Acoustic Bridge and Saddle - Two more very important components found on the guitar body are the saddle and bridge. The bridge is a strip of wood, usually ebony or rosewood, that is glued to the face of the soundboard. The bridge serves as the other termination point for the strings, which are secured via bridge pins. A saddle, made of plastic, ivory, or composite materials is inserted into a groove in the bridge and underneath the strings. This critical piece serves to transmit all of the string vibrations to the bridge where it is then transferred to the soundboard. The position and angle of the saddle ensures proper string intonation as well as controling the string height.

• Electric Bridge and Saddle - Electric guitars also have a bridge and saddle, but their purpose is a bit different. The bridge serves as a method for mounting and securing the end of each string while the saddle controls the string intonation and height. String vibrations are transferred to the guitar body through these two components, but they do not directly affect the guitar's tone nearly as much as they do on acoustic guitars. Some electric guitar bodies, like hollow-body electrics, are built similarly to acoustic bodies. However, the principle means of producing sound still remains with the pick-ups. The vibrating air inside the hollow body simply affects the tone and color of that sound.

The Ancient Guitar

Guitar-like instruments are very old and existed in the cultures of central Asia and India thousands of years ago. The Persian tanbur and setar, as well as the Indian sitar, are considered distant relatives of the modern guitar. However, stringed instruments of inumerable variations have existed for many years the world over. So, it is difficult to trace a direct lineage to these ancient instruments. Many similar sounding names like the Arabic qitara, the Latin cithara, and the Greek kithara (all of which are believed to have been derived from the Persian sihtar) have misled musicologists over the years. It is now believed by most that the modern guitar is more likely descended from a convergence of two instruments: the Moorish oud, which was introduced in Spain during the Moorish invasion of the 8th century and the Scandinavian lut (lute).

The Medieval and Renaissance Period

There are records of two medieval instruments around the 13th century under the names guitarra moresca and guitarra latina. These instruments had four courses (a course is a pair of strings played together, like the modern 12 string guitar). Their design was tantalizingly similar to more modern guitars and may well have been influential in the instrument's development. However, the earliest antecedent that most scholars agree on is the Spanish vihuela, which appeared around the 15th and 16th centuries. The vihuela had six courses, was tuned in fourths, and had a guitar-like body. Some vihuelas were played with a bow, which gave rise to the renaissance viol. However, by the 16th century vihuela construction, with it's curved bouts, was beginning to resemble the modern guitar. The vihuela enjoyed a wide popularity on the Iberian peninsula while the lute was more dominant throughout the rest of Europe.

The Baroque Guitar

By the 17th century the baroque guitar, with five courses and containing elements of the earlier moresca and latina guitars, quickly superseded the vihuela. These grew in popularity in Italy, which for a time became the center of the guitar world. The five courses of the baroque guitar became the standard for some time. Around this time the standard tuning of A, D, G, B, E was settled and is still in use today (excepting the final low E for modern six string guitars). The neck length on the baroque guitars was more like that of a lute, with only 8 to 10 frets extending past the body. By the late 17th century a sixth course of strings had been added by Italian makers, resulting in the standard number and tuning that we see today.

Approaching its Modern Form

From this point, guitar leadership and innovation switched back to Spain where numerous changes were made. By the close of the 18th century the six pairs of strings had been changed to six single strings. Throughout the 19th century Spanish designers such as Antonio Torres innovated and made lasting changes to the guitar. Torres introduced his revolutionary "fan" type bracing pattern, which has been adhered to by many guitar makers ever since. He also increased the size of the body and altered its proportions, giving it a shape that more closely mirrors today's guitars. All of these things served to increase the instrument's volume and tone projection. Concurrently, the German immigrant C. F. Martin had begun developing his X-brace pattern. This quickly became the standard for steel string guitars when steel strings were introduced around 1900.

It was at this point that the acoustic steel string guitars diverged from what are now called classical guitars. The former required a stronger construction to withstand the tension of steel strings while the latter maintained a lighter construction. Classical guitars soon began to use nylon strings in place of the former animal gut that had been used for centuries. Another variation was developed at the end of the 19th century - the archtop guitar. These incorporated a bowed top, much like a cello, and strings that terminate at the bottom of the guitar body instead at a bridge glued to the guitar top. This floating bridge allows the soundboard to vibrate more freely and produce a unique sound that is popular with jazz and blues players.

The 20th Century Guitar Revolution

There remained one major innovation for the guitar during the 20th century. This was the introduction of electronic amplification. With it was born the electric guitar, which is typically a solid body mounted with magnetic "pick-ups" that sense the strings vibrations. These vibrations are then sent to an amplifier for sound projection. The electric signal can be altered in myriad ways to produce effects and gradations of sound that are impossible with other guitars. It goes without saying that the electric guitar has revolutionized the instrument and thrust it into its prominent place in the musical world.