The body works like the speaker of an acoustic guitar – it’s the biggest thing that dictates how a guitar will sound.

Vibration of the guitar’s strings is transmitted to the top of the body via the bridge which in turn transmits vibrations to the back and sides. The sound of the guitar is the result of these 3 sides and the air inside the body moving together. A small change in any element of the body – shape, size or material – will change the sound of the guitar.

The human hand is incredibly sensitive, so the exact shape and size of a guitar’s neck makes a huge difference to how the guitar feels, but the neck also has a substantial influence on the instrument’s tone and sustain.

So it doesn’t twist or warp, the hardest, densest woods are used to make necks: mahogany, rosewood, nato, padauk, and sometimes maple. Necks can be carved from a single piece of wood, or from several pieces joined together for added strength and rigidity. Yamaha combines mahogany with rosewood, padauk, or ebony in three piece and five piece necks, blending the strength and sound profiles of the different woods for the desired result.

Although primarily a playability issue, the shape of a neck also affects its overall mass, which has an effect on tone – more mass means a fatter, thicker tone. The profile of the neck can range from a somewhat flattened “D” through a rounded “D” to a distinct “V” shape. The choice is deeply personal, and Yamaha has spent many years researching and refining neck shapes to build neck shapes which suit the different characters of each guitar model while balancing comfort and playability with strength, stability and great tone.

The length of a guitar’s neck, also called the scale length, changes the feel and sound of a guitar. A shorter neck, like the neck of an FS which is just a few millimetres shorter than standard, will feel more comfortable and will give a guitar a brighter, clearer tone.

The bridge is where the strings anchor to the top of the guitar and on an acoustic guitar usually consists of two main components: the bridge base and the saddle. The saddle rests in a groove in the bridge base, which is glued directly to the top of the guitar. Holes are drilled through the bridge and top of the guitar for the strings to pass through. Wedge shaped bridge pins hold the strings in place.

The bridge has two core functions – transmission of string vibrations to the guitar’s body, and control of the string length, which determines tuning accuracy along the fretboard (referred to as the guitar’s intonation).

To help string vibrations be transmitted efficiently to the body with minimum damping, relatively hard materials are used for both the bridge base and saddle. The bridge base is generally made of a dense hardwood such as ebony or rosewood, while the saddle will be made of hard resin or bone. Ivory was considered the best material in the past, but has been illegal for many years. New synthetic materials are becoming popular due to a good balance of tone, durability and sustainable production.

The materials used for the bridge have a considerable effect on the guitar’s tone – harder materials like bone give a clearer, brighter tone but are more expensive, more difficult to work with and more fragile.

The strings rest on the saddle, which is precisely shaped to control the height and match the curvature of the neck.

To maintain proper intonation for all six strings, so a string played at the 12th fret is exactly on octave above the open pitch, the saddle is installed at a precisely calculated angle, with the high E string end a little closer to the neck than the low E string end. The third (G) string sometimes requires a slight offset in the saddle to achieve proper intonation. On an acoustic guitar, this can’t be adjusted easily, so it’s vital that the guitar is designed and made well so the bridge is in the perfect place when it’s new, and it doesn’t move even after years of being played.

When you play a guitar, you feel the wooden fingerboard and the metal frets inlaid into it more than any other part of the instrument. They affect the sound, the feel and the tuning of the guitar, so picking the right materials and making sure they’re put together correctly is essential.

Hard, dark woods like ebony and rosewood are the most commonly used fingerboard woods as they provide an ideal blend of durability and resilience along with a good tone.

The exact position of a fret between the nut a bridge of a guitar determines the pitch of a note, so the fret grooves are cut into the fingerboard using precision computer controlled cutters to make sure they’re in exactly the right place. The material, height, width, and overall shape of the frets themselves also affect playability, tone, and intonation, so frets are manufactured and installed with the utmost care. Yamaha’s combination of computer-controlled processes for accuracy and the sensitive touch of a craftsperson is the best way to do this.

The guitar’s strings are suspended between the bridge on the body and the nut at the headstock, and it is the distance between the bridge and nut that determines the pitch of the open string. A tiny change in string length can make accurate tuning impossible, so precision is extremely important.

The nut has grooves in which the strings rest that are carefully cut to the perfect size and shape of each string. The depth of each groove is precisely set by a craftsperson for each string to make sure it’s the perfect height from the frets so it’s easy to fret without causing any buzzing.

A guitar’s nut is usually made of the same material as the saddle – hard resin, bone or advanced synthetic materials; harder materials are generally better.

Tuning machines are sometimes called machine heads, tuning keys, tuning pegs or tuners. Each string passes through the nut and is attached to a tuning machine on the headstock. The tuning machines can be arranged along one side (six in a row) or on each side (three per side) of the headstock.

Rotating the key on the tuning machine wraps the string around the tuning machine’s post pulling the string tighter and raising its pitch.

Good quality tuning machines are engineered so the post doesn’t move unless you turn the key, helping keep the guitar in tune.

The tension produced by a tuned up set of steel strings is considerable, and will bend even a very stiff neck, pulling the headstock towards the neck and making the neck a ’U’ shape. If there is too much of a curve in the neck, the guitar will be hard to play because the strings are a long way from the fretboard.

To counteract this force, steel string guitars have a metal bar called a truss rod embedded in the neck with an adjustable nut on one end that can be adjusted to straighten the neck and compensate for the tension of the strings. The adjustment nut can usually be accessed either via a removable cover on the headstock, or at the body end of the neck through the sound hole.

Almost all guitar necks will need adjustment from time to time due to weather changes or if you change string gauges, but a well installed truss rod will give easy and accurate adjustment throughout the life of a guitar.

Nylon string guitars don’t usually need a truss rod because the tension of nylon strings is much lower than steel.

The woods used in a guitar and the way they are combined are fundamental tone shaping elements. There is no “best” wood or combination: the individual player’s tonal preferences and needs are the ultimate deciding factors, but there are basic requirements for strength, stability, and tonal balance that guide the selection. The chart below lists some of the woods used for various parts of Yamaha guitars along with their source and main characteristics.

There are 2 main types of wood used for acoustic guitar bodies: solid wood is a single piece of natural wood; laminated wood consists of multiple (typically three) very thin layers of wood glued together.

Solid wood generally sounds better than laminated wood because it transmits vibrations more effectively than layers of wood joined together with glue, but it’s more expensive, more fragile and more sensitive to changes in temperature or humidity.

All solid woods are not equal, so it’s not possible to say that solid always sounds better than laminated wood. A well designed guitar made of laminated woods, where the wood thickness, material choice and glue formula are perfectly refined, can sound good and be extremely durable.

Because it’s where most of the vibrations occur, the top of an acoustic guitar is where the biggest difference between solid and laminated woods can be noticed.

The shape of an acoustic guitar body changes the look of the guitar, but also has a significant effect on the tone.

A bigger bodied guitar will generally have a ‘bigger’ sound, meaning more low and high frequency (or bass and treble) response. A smaller body will result in a ‘smaller’ sound, where there is less low and high frequency response and a stronger midrange tone.

Different tones suit different players, different styles of music and different applications. Yamaha has many different body shapes, each designed to sound, look and feel different – the changes are relatively small, but the differences are noticeable.

For players who want access to the highest notes on the guitar, cutaway bodies allow your fretting hand to get much higher up the neck without the body getting in the way.

An acoustic guitar’s top is very thin, so to stop it bending and cracking under the tension of the strings, thin strips of wood – or bracing – are glued to the underside to reinforce it. Gluing the bracing to the top of the guitar, which is the primary source of the guitar’s sound, changes the vibration of the top, and therefore the guitar’s tone.

Bracing design balances its structural role with the enormous effect it has on the tone of the guitar. There are many factors which can be adjusted including the shape, size, profile and layout of each strip of wood (there can be ten or more under the top of an acoustic guitar) and the exact combination of these elements is probably the most important thing in determining the character of one guitar against another.

Traditionally, bracing was designed using trial and error – with a luthier adjusting the layout, and shaping and shaving the braces until it sounded good, using experience to judge if it would be strong enough to keep the top flat for many years.

Yamaha’s latest acoustic guitar designs use specially designed computer simulations to determine the exact shape, size and placement of each brace in order to give the desired tonal response and perfect strength.

The point where the neck and the body of a guitar join is extremely important. It has to be strong so the neck doesn’t move, but because the vibration of the neck and head contribute a lot to the sound of a guitar, it also has to transfer vibrations efficiently back to the body to get the best possible sound. The shape of the joint, and how precisely it fits together, has a big effect here.

All Yamaha acoustic guitars (except small-size guitars like JR1 and APXT) use a hand-fitted, modified dovetail neck joint where the exact shape of the neck and the corresponding slot in the body are precisely matched and shaped by hand, then fitted together using only a tiny amount of glue. This painstaking approach ensures that every Yamaha guitar is perfectly built for lifelong stability and the best possible sound.

Yamaha’s Acoustic Resonance Transducer (ART) pickup is a contact pickup which attaches to the underside of the guitar’s top. Because the pickup senses both the vibration of the wood and the air around it, the sound is dynamic, natural and extremely responsive to body tapping.

The pickup was designed from scratch for acoustic guitar, with every element being tailored to optimise tone – even the adhesive which mounts the pickup onto the guitar’s top was chosen based on how it sounded.

Yamaha’s SRT system uses a precisely matched pickup and preamp system to reproduce the sound of your guitar as if it were picked up by microphones. Digital Signal Processing (DSP) models the sound of the microphone, the air around the guitar, the room is was mic’d in and all of the parts of the guitar to create a natural sound without any mic’s.

Each model has to be recorded to create the sound which the SRT system will recreate, but this process means the amplified sound is as close to the acoustic sound as possible.

SRT2 is the latest pickup system developed by Yamaha, and optimized for stage performance.

SRT preamps allow blending between the raw pickup sound and the SRT modelled mic sound to find the perfect balance between a natural mic tone and the cut-through capabilities of an undersaddle pickup.

SRT2 features 2 different types of microphone sound as well as bass and treble EQ to get a perfect sound for any style, venue or session.

SRT Powered is featured on the Silent Guitar series and uses the same pickup and preamp technology as the SRT system. As the solid bodied Silent Guitar doesn’t have a natural acoustic sound to recreate, the SRT powered system blends between the undersaddle pickup and a single, idealised microphone tone.

The SRT Zero Impact Pickup system is Yamaha’s exclusive passive undersaddle pickup and an essential element of the SRT system. Designed to minimize the pickup’s impact on the tone and traditional appearance of the instrument, the system uses individual pickup elements for each string to give a much more powerful, dynamic, natural tone than traditional undersaddle pickups. It can be used passively, direct to a jack socket, or with an SRT preamp.

TransAcoustic guitar features reverb/chorus built-into the guitar to provide inspiring, engaging acoustic sounds with no need for external effects, amplification or technical knowledge.

1. Pickups under the saddle detect string vibrations

2. A preamp processes the signal, applying effects such as reverb and chorus

3. The actuator attached to the rear of the body outputs this signal

4. The body of the guitar becomes the speaker for the system, with the effects seamlessly blending with the acoustic tone without any need for external amplification or speakers