The Anatomy Of An Acoustic Guitar (An Illustrated Guide)

• All the parts of an acoustic guitar explained!
• Learn the form, function, and material of each guitar component.
• Discover some new terms you were too afraid to ask about!
  
• You may also want to check out our acoustic guitar buying guide!

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David Schiller called a guitar “the world’s most seductive instrument“. I concur as one of the lucky blokes who got that book as a gift.

Now, before you think it is redundant or optional to study guitar anatomy, ask yourself – do you want to be the person who goes to the guitar shop asking for “that metal thing to hook the strap onto?”.

So, whether you are new, curious, or nerdy, we will break down all the pieces of an acoustic guitar, visually and verbally.

(For a full rundown of each type of acoustic guitar, check out Types Of Acoustic Guitars (An Illustrated Guide & Breakdown))

Components of Steel String Acoustic Guitars

Headstock / Head / Peg-Head

The primary role of the headstock is to facilitate the tuning pegs that hold and tune the acoustic guitar strings. It also sports the branding (logo) and serial number to identify the guitar. A good headstock will keep the guitar balanced while a bad one is a neck-dive nightmare.

Generally, acoustics have a symmetrical 3+3 headstock – three tuning machines on each side. Headstocks are connected to the neck with a scarf joint or finger (toothed) joint.

The headstock has always been a style statement. Flattops by Seagull, Gibson, Guild, and others have a distinct headstock shape that makes them instantly recognizable.

Commonly used material: Laminate or Solid Wood with or without veneer.

Tuning Pegs / Machine Heads

Tuning machines are placed three-to-a-side on the headstock. The acoustic guitar strings are wrapped around a string post protruding from the face of the headstock (called a Capstan). The tuning pegs (head) sticking out from the side can be turned to tune up or tune down the guitar.

In simple words, tuning machines are the knobs on the headstock to tune up or tune down your guitar. Some tuning pegs are better than others, typically due to the build quality and gearing ratio sensitivity.

Commonly used materials: Stainless steel and plastic (outdated)

Fretboard / Fingerboard

With guitars, the fretboard refers to the long, thin strip of wood (or laminate) that rests on the neck between the nut and the soundhole. The guitar strings run along the fretboard, and pressing them down at any point will alter the string’s vibrating length to change the note’s pitch.

The fretboard hosts frets, fret wires, and inlays. They are also referred to as fingerboards, depending on which side of the pond you are at. Ebony, rosewood, maple, and other hardwoods are popular construction materials.

Neck

A neck does not refer to the fretboard; the two are categorized separately. An acoustic guitar neck is a long plank that contains the frets, nut, and some form of reinforcement. It is topped with a fretboard (or fingerboard) that contains fret wires and inlays (fret markers).

Traditionally, the neck of an acoustic guitar is made from a single piece of wood (quartersawn Mahogany) and attached to the body with a dovetail joint. Nowadays, several varieties and techniques are used due to cost, availability, and other consumer considerations.

Some guitars have a wider neck while others are fast and slim. You can replace an acoustic guitar neck if it is damaged beyond repair. Unless you have the craftsmanship, the process is best done by a professional or luthier (guitar engineer).

Commonly used material: Mahogany, Maple. Padauk, Walnut, etc.

Nut

The guitar has two points that determine the length of the vibrating string – the nut and the bridge. The nut is a plastic or bone strip with six grooves or notches at the neck’s tip. The nut holds the strings in place.

The strings pass through the nut. It sets the vibrating length for open strings and prevents them from vibrating into the headstock. Generally, an entry-level instrument ships with a synthetic or plastic nut. Bone and synthetic bone nuts are popular upgrades.

In a nutshell, the nut influences string spacing, sustain, open string vibration, and action. Some guitar manufacturers offer a ‘compensated nut’ for improved intonation (more accurate). Replacing a poor-quality nut with a bone nut can make a marked difference in the tone.

Commonly used materials: Plastic, Synthetic materials (Nubone, Tusq, Micarta), Bone, Ivory

Truss Rod / Neck Reinforcement

Unlike their vintage counterparts, all modern acoustics are fitted with a truss rod and/or neck reinforcement (steel tube/carbon fiber). The main function of neck reinforcement is to counteract the string tension and adjust the neck.

Depending on the type of truss, it can be used to make adjustments to fix the neck-warp caused by humidity and temperature and raise or lower the playing action (string action). Two-way truss rods are the most adjustable and can fix both up-bow and back-bow warping.

A ‘neck reinforcement’ keeps the neck straight – it is not the same as an adjustable truss rod. Look for the term “adjustable” when you buy an acoustic. A two-way truss is ideal, among which “X-reinforced fully adjustable rod” is the best type.

If you’re new to acoustic guitar, check out 7 Best Low Action Acoustic Guitars (All Budgets).

Frets & Fret Wire (Fretbar)

The width of the guitar neck (fingerboard) is divided into small compartments called guitar frets. A fret refers to the gap between two fret wires (metal strips) and represents a pitch (semitone).

When the guitarists press the string against the fret wire, it reduces the vibrating length of guitar strings to alter the pitch. Traditional acoustics (with a non-cutaway body) have 19 to 21 frets, of which only 14 are easily accessible.

Inlays / Fret Markers

Guitar inlays are dots or positional markers placed on an acoustic guitar on frets 3, 5, 7, 9, and 12. Generally, they are placed on the neck, but some guitars also have dot inlays to the side. Some guitars don’t have inlays, but you can replace or remove the inlays on any type of guitar.

Functionally, they are a visual cue to identify the position of the fretting hand. Besides that, it’s an aesthetic thing, and guitars would look incomplete about them.

Some guitar makers use a unique inlay to differentiate their brand from the competition. The dove inlays of PRS guitars and the Gibson-style trapezoids are examples.

Commonly Used Materials: Mother-of-Pearl, Plastic, Abalone, Wood

Soundboard / Guitar Top

The face of a guitar is called the soundboard (short for sounding board) and plays the most important role in producing the tone. When you hit a string, it vibrates the top wood. The vibration moves through the bridge and into the soundboard.

In a nutshell, it’s a key component in your guitar’s tone and sound quality. That’s why a solid-top is a significant upgrade from an all-laminate guitar. Soundboards have a sound hole and being thin, they invariable have a system of struts to “brace” the guitar.

Common materials: Laminate, Spruce, Mahogany, Cedar.

Soundhole

Most acoustic guitars have a round sound hole placed under the strings. The primary function of the soundhole is to facilitate the release of the “air” when you play notes of chords. Air refers to the internal resonance created in the hollow chamber.

The size of the soundhole varies based on the make/model and type of guitar (Jazz manouche guitars, Selmer guitars, etc. ). Some guitars sport f-shaped holes and may even have an off-center or ported soundhole (i.e. Ovation Guitars, McPherson Guitars, and Taylor w/ Soundport Cutaway).

Bracing

Acoustic guitar bracing refers to a lattice of wood strips on the underside of the guitar top (soundboard) to give to more structural integrity. The bracing uses light but strong timber struts in a specific pattern to keep the top from succumbing to string tension over time.

The type of bracing influences the sound. That’s why we’ve got X, Double-X, Scalloped, V-Class, Fan bracing, and a long list of variations. X-bracing, developed by C.F. Martin & Co, is one of the earliest and still the most common type of bracing in steel-string guitars.

Pickguard / Scratch Plate

The pickguard is a part-aesthetic and part-functional feature. Acoustics didn’t have them until the late 1920s. Martin was the first guitar manufacturer to introduce them, and being a trendsetter in all things acoustic, other brands followed suit.

The primary function of a pickguard is to prevent scratches on the soundboard (top) and guitar finish. Aggressive strumming causes the guitar pick to flick against the wood, causing scratches and nicks over time.

Most are a 2mm sheet of Pearloid or plastic stuck to the guitar top with an adhesive. They wear out, so a trip to the repair shop is due.

Pickguards come in two types: a teardrop pickguard inlaid into the guitar with an adhesive, or a floating pickguard typically found on acoustic archtops like the Gibson L-1 and Fender Tim Armstrong Hellcat. Again, many brands have altered their pickguard design to produce visually distinct instruments.

Gibson Dove (or SJ-100), Epiphone Hummingbird, and Gretsch Rancher are some examples. Conversely, even today it is common to find acoustic guitars without a scratchplate. Taylor (V-Class), Breedlove (Pursuit), Martin (Little Martin), and others offer acoustic guitars without a pickguard.

Commonly Used Material: Mother-of-pearl (Pearloid), Acrylic, PVC/Plastic

Rosette

In an acoustic guitar, the Rosette (French for little rose) is an ornamental ring along the edges of a soundhole on an acoustic. Contrary to popular belief, the Rosette is not purely ornamental. It provides structural integrity to the soundhole to prevent cracks and chipping along the edges. Manufacturers use unique soundhole designs to make their instruments easily identifiable.

Body / Back and Sides

The guitar’s body is composed of the top, back, and sides of your guitar. These three elements determine the different shapes of the body. The measurements are noted as the upper bout, lower bout, and body depth.

The back and sides are either made from laminate or solid wood. They play a significant role in the tone of the instrument. Any guitar with solid wood back and sides is better-sounding and more expensive than its laminate counterpart.

Commonly Used Materials: Rosewood and Mahogany

Strap Buttons / Strap Pin

Some acoustic guitars have strap buttons – wooden or metal pegs strategically placed on the body to hook a guitar strap and keep everything well balanced.

Acoustic guitars can have one, two, or no strap buttons based on their make/model. Strap buttons can be installed, removed, and replaced by the owner or a guitar technician.

Acoustic Guitar Strings

Acoustic guitars use metal strings or nylon strings (classical guitars). They are available in various types (nickel, phosphor, bronze, steel) and string gauges (light to heavy). You can tune them to different pitches using the geared mechanisms on the headstock.

To be precise, strings are not a part of the actual guitar. They can be removed and replaced at will and are categorized as guitar accessories. However, being such a crucial part, they deserve a mention here.

Bridge

The bridge is a single-piece strip made from carved wood or laminate with countersunk pin holes for bridge pegs and a slot for the saddle. It is glued to the guitar body (top).  The main function of the bridge is to hold the strings fast at a pre-determined height and transfer the string vibrations.

Bridges can affect the sound slightly. Material is the decisive factor in how it will impact the tone and resonance. It’s a minor change, best left to audiophiles and tone hounds.

Commonly used materials: Ebony and Rosewood are the most coveted. Followed by Maple, Mahogany, Ovangkol, and a slew of cost-effective substitutes.

Bridge Pins / End Pin

In an acoustic guitar, the main function of a bridge pin is to secure the string’s ball-end to hold it firmly in place. A bridge pin carries the sound (string vibration) into the soundboard.

The material/quality of a bridge affects the tone, sustain, and volume of an acoustic. For that reason, high-quality ebony bridge pins are considered better than cheap ‘stock plastic pegs’.

The mechanism is very different from the ‘tie the strings’ version in classical guitars. Beginner to intermediate guitars ship with plastic bridge pins.

Ebony or bone pins improve clarity, volume, and sustain. There are lots of materials to experiment with, each with a distinct capacity to steer your tone towards more treble or bass.

Material: Wood, Ivory, Bone, Horn, Plastic, and Synthetic.

Saddle

The saddle is a thin strip of bone, plastic, or other materials placed in the notch of the bridge. The strings sit on the saddle and it influences the instrument’s string action and tone.

It can be filed to raise or lower the string action, but this process needs precise measurements and expertise. If you ever notice the term “compensated saddle” it indicates that the saddle is angled for better intonation.

Binding

In an acoustic guitar, binding is primarily used to hide the end grain or to give added protection to the edges and the soundboard. It’s largely considered to be a cosmetic addition.

Guitars with softer tonewoods (Cedar) have binding while Mahogany guitars forgo the process altogether. Some people prefer the classic/minimal no-binding look and others prefer glitzy abalone purfling.

Acoustic Guitars vs. Electric Guitars

Acoustic and electric guitars share the same inherent design. The main differences in anatomy are that electrics generally have a solid body (no chamber) as compared to an acoustic’s chambered body (hollow and semi-hollow electric guitars notwithstanding).

Electric guitars have paltry unplugged volume and projection due to the absence of a sound hole and body chamber.  They reply on pickups and electronics for amplification. Nevertheless, the same playing techniques apply to both instruments with few differences.

Wrapping Up

The guitar body is a work-in-progress that continues to evolve and improve. When browsing for acoustic guitars, you will find massive variations as manufacturers constantly try refining body shapes and components to set apart their designs.

Something as innocuous as fretboard timber, headstock overlay, bridge material, and fretboard wires can have a tangible impact on the tone of steel-string acoustics.

That’s why one guitar, no matter how awesome, is never enough. If you agree, head over to our roundup of the 7 Best Acoustic Guitars Under $1000 to look for your next dream acoustic guitar!