TYPEs of guitar

Body

The body of an acoustic guitar is made up of the soundboard, or top, and the back and sides. The soundboard is the part that vibrates to produce sound, which is why top tonewoods are considered so important, but the back and sides contribute to the tone as well (read more about how top vs. back and sides affect tone in our article “Your Tone Begins with Your Top”). From top to bottom, the body is divided into the upper bout, the waist, and the lower bout. Bouts are measured across the width of the guitar, with the lower bout being slightly larger than the upper bout.

There are many types of guitar body sizes and shapes, including models with cutaways, or scooped indentations in the guitar’s upper, treble-side bout (the treble side is the side of the first string). In general, a bigger box means a bigger sound, but some guitars will surprise you with qualities not typical to their body style. (We will cover this topic in greater depth in a future post.)

Neck

The neck of the guitar projects from the main guitar body and includes the fretboard, frets, headstock, and truss rod (which stabilizes the forward curve, or “relief,” of the neck, keeping it from bending due to the tension of the strings). Necks have different shapes, from more of a V shape to a C shape and every point in between. The rigidity of a guitar’s neck is indicative of the quality of the instrument. Some give can be desirable, as bending the neck slightly to change the pitch of a note is a common technique in blues and rock.

Fingerboard (a.k.a. Fretboard)

Laminated to the front of the neck is the fingerboard or fretboard, by far one of the most important parts to consider when selecting a guitar, as it affects comfort, playing style, and tone. It is generally made from a different type of wood as the back of the neck and is fretted. Ebony, rosewood, and maple are typical woods used, though synthetics such as Richlite are another option.

Frets

Guitar frets are raised parts on the fingerboard of the guitar that extend across the full width of the neck, and are generally made of metal. Frets divide the guitar neck into intervals, each fret representing one semitone of an octave. Pressing the string against the fret shortens the string to the length between the fretted point and the bridge, changing the note and making it easier to achieve correct notes than a non-fretted fingerboard. Frets come in different shapes and types, and will wear over time, which makes fret maintenance important.

Position Markers

Guitars often have dots or custom marks inlaid into the fretboard as a visual aid to the player. These markers are usually on the third, fifth, seventh, ninth, twelfth, and fifteenth frets, with the twelfth (octave) fret often being different than the others (for example, two dots instead of one). Most classical guitars do not have position markers.

Nut

The thin piece of material that supports the strings on the end of the neck of the guitar closest to the headstock is called the nut. This important piece, usually made of ebony, ivory, brass, or synthetic materials, holds the strings at the proper height from the fingerboard and is notched to set the spacing between them. Why “nut”? The word likely derives from the German Nut, meaning slot or groove.

Headstock

At the top of the neck is the headstock or peghead of the guitar, which holds the tuning pegs and keys that allow the guitar to be tuned. Headstocks can be straight or angled, and come in many different shapes depending on maker and model.

Capstan (a.k.a. String Post)

Capstans or string posts are cylinders on the headstock with a hole in the center through which guitar strings are inserted. They are connected to the whole of the machine head mechanism, traditionally mounted at the center of a pinion gear.

Tuners (a.k.a. Tuning Keys, Machine Heads, or Tuning Pegs)

Tuners or machine heads rotate the capstan to wind the string around it by way of a pinion gear and a worm gear, increasing or decreasing tension in the string to raise and lower pitch. Machine heads vary from instrument to instrument. On nylon or classical guitars, the worm gears are usually exposed, while on steel string guitars they are generally placed inside of a casing with lubrication. Vintage and vintage-recreation guitars have open-gear tuners, since enclosed gears were not common until after World War II.

Sound Hole

Sound holes help with sound projection, though it is a misconception to think this is the main source of a guitar’s sound. The entire surface area of the guitar top, or soundboard, emanates sound, with the hole allowing the soundboard to freely vibrate, and acting as a sort of escape valve for vibrating air. (For this reason, we usually avoid pointing a mic directly into the sound hole when recording guitar. Watch our X/Y recording masterclass for more info.)

Sound holes are usually centered in the body and circular, but some builders have distinctive innovations in sound-hole design, such as McPherson’s unmistakable offset sound holes that are designed to allow greater vibration in the center of the guitar top.

Rosette

The decorative inlaid pattern around the sound hole is called the “rosette”: originally a round, stylized flower or botanical design derived from the diminutive for “rose” in French. Rosette patterns range from modern and simple to ornate, and builders often choose a specific rosette design to help brand their lines.

Pick Guard

The pick guard or scratch plate of the guitar does exactly what its name indicates: protect the soundboard from being scratched or damaged by a pick. Pick guards can be made of any number of materials, such as mother of pearl or pearloid, plastic, metal, acrylic, and exotic woods. They are very thin so as not to reduce the vibration of the soundboard.

Bridge

The bridge of the guitar supports the strings and transmits their vibration to the soundboard. Strings produce a very low sound on their own because they displace only a tiny volume of air as they vibrate. The vibration of strings therefore needs to be conducted to a larger, resonant surface, and a bridge is the usual way of achieving this on stringed instruments. Bridges may consist of a single material, usually wood for acoustic guitars, or they may be made of several parts and include other materials such as plastic or bone. On classical and steel string guitars, the bridge is glued to the top.

The soft, soothing sound of nylons strings

Acoustic guitars and electric guitars use steel strings, whereas classical guitars use nylon strings. Strings 1 through 3-the strings that produce the high pitched treble tones-are a single, transparent nylon string. Strings 4 through 6-those that produce low base tones-are usually silver in color, but consist of around 200 individual strands of nylon wrapped with silver plated copper thread.

The major characteristic of nylon strings is the soft, pleasant sound that they are able to produce. Nylon strings have large vibrational amplitude when plucked, and require sufficient space between strings to ensure they do not hit the adjacent string. The neck of the guitar is wider than usual, to allow the player's fingers to press down a string without coming into contact with other strings during fast musical pieces.

The left hand thumb does not press the strings

The classical guitar has a wider neck, which changes the way the strings are pressed when compared to acoustic guitars and other designs. Compared to acoustic guitars, where the guitarist seemingly grasps the neck and presses down on strings with the thumb, the guitarist's thumb does not come into contact with the strings when playing a classical guitar. Instead, the thumb presses against the back of the neck to support the other fingers. All the remaining four fingers are used to press down the strings.

Four fingers are used to pluck the strings, with the thumb acting as a support.

As for the width of the neck, a typical Yamaha classical guitar has a neck width of 52 mm, while that of a Yamaha acoustic guitar is 43 mm, demonstrating that the classical guitar neck is about 1 cm wider. The cross-section of an acoustic guitar neck is triangular, whereas that of a classical guitar is a semicircle.

The pitch rises along with the temperature

As the temperature of a classical guitar rises, so does its pitch. Likewise, a decrease in temperature means a lower pitch. This is because the synthetic fibers in polymers such as nylon that are used in the strings of classical guitars tend to contract when the strings warm up under a certain amount of tension. This phenomenon is called the "Gough-Joule effect." This causes the strings to contract as the temperature of the guitar rises, increasing tension and causing the pitch to rise. This is especially the case with thicker nylon strings such as strings 2 and 3, while there is little change at all to strings 4, 5, and 6 (which are wound with metal).