Navigating the surfeit of guitars available at your local music shop or online retailer can be a daunting experience. The sheer number of models, shapes and sizes is confusing. However, there might be a way to simplify the experience with the use of science.
The guitar as a crafted instrument relies heavily on science for its construction as well as the sound it produces. The measurements and fine-tuning that go into making a guitar are extremely precise.
An understanding of the science behind the guitar is, therefore, an invaluable tool to measure quality, and therefore, determine what is the best guitar.
Tone-wood and Sound Waves
Sound travels differently through varying materials. It moves through wood nearly thirteen times faster than air. This makes it an ideal material for musical instruments where responsiveness is key. We know that sound waves cannot travel in a vacuum. They require molecules to interact with to produce what we recognize as birdsong, a car engine, or music.
The first instrument makers sought out the best material and settled on wood. We’ve all heard of Stradivarius violins. The luthier Stradivari was obsessive about quality and would only use spruce wood from the Fiemme Valley in the Italian Alps. His violins are now famous for the uniqueness of their sound and have the price-tag to match, with certain copies selling for millions of dollars.
Wood is favoured because of its capacity to effectively transport sound. It also has tonal qualities that differ depending on the type. Some produce brighter sounds, while others create warmer, deeper overtones. In guitar jargon, it is called tone-wood. An especially dense wood prized for the resonance of the sounds that travel through it and the propensity to shape the sound of a finished instrument.
Choosing the right type of tone-wood is an important scientific measure of the best and worst guitars. This is, however, hindered by the availability of certain tone-woods which has a direct impact on the price of a guitar. The rarer, more endangered, the wood, the more costly the instrument. It is best to rely on the specific qualities of tone-woods to determine which most suits your needs.
Another consideration is the structural value of wood. A guitar needs to hold itself together as well as produce a great tone. Guitars are known to sustain tension amounting to a few hundred pounds. Luthiers therefore search for a happy medium between tonality and strength.
Here is a list of the most common tone-woods and their respective qualities. This is by no means exhaustive and many other variants exist with similarly scientifically proven attributes.
Ash: A common, bright sounding wood known for its ability to sustain chords and notes. Ash is one of the strongest, and most economical, woods used in guitar making. Native to Europe, it is widely available and very affordable.
Alder: Also found in Europe, it is known for its low weight, and a balanced, rich tone with a generous share of both high, mid-range and low frequencies. Alder is favoured for blues and rock styles. Low priced compared to woods such as mahogany and is readily obtainable.
Basswood: One of the softer tone-woods, basswood is native to the Americas. It is used for the balanced, but ever so slightly warmer, quality of its tone. Very affordable and often seen in mixed-wood guitar models.
Mahogany: An extremely resonant hardwood that favours warmer tones, mahogany is strong, but malleable, making it a favourite of luthiers the world over. It is favoured for its durability, pleasing red color and ability to produce a rich, but twangy sound. Mahogany is heavy so be prepared for the extra weight when playing.
Maple: Primarily used for the neck and fretboard, maple produces an extremely bright sound due to its hardness. Found primarily in North America, Maple resonates well and produces defined, biting tones. Maple is mainly used on guitar necks or used with woods to balance out dark, muddier tones.
Rosewood: A heavy and visually stunning tone-wood, rosewood is most often incorporated into a build on the fretboard. It produces a rich, loud and velvety sound though at a high cost due to its rarity. This is definitely not for the more ecologically minded player.
Electric Guitars and the Tone-wood Fallacy
The importance of tone-wood cannot be understated when considering an acoustic guitar, but does it have the same impact on an electric guitar? Though enthusiastically debated to this day and marred in a conflict-ridden history, the short answer is a science-backed resounding no, or at the very least, the impact is very small.
Electric guitars use magnets and electronic circuitry to carry the sounds from the vibrating strings to an amplifier. The wood has no substantial impact on the quality of the vibrations which create the sound.
Unlike an acoustic which uses the wood to amplify and enlarge the sound, an electric guitar doesn’t rely on the wood to do so. The wood simply acts as a strong base capable of sustaining the tension of the strings and onto which the other components are fixed.
Choosing an electric guitar is, therefore, much more reliant on the components, the quality of the craftsmanship and how these two affect the tone.
The basic premise of acoustic guitars is the transfer of the natural sound of the strings to the body of the guitar. This cavity then acts a resonance chamber where the sound waves from the strings cause the wood of the guitar to vibrate. The air inside the chamber then distorts and creates compression waves which are then amplified. This travels out into our ears, which translate it to sound or music.
In general, the wood used on the back plate and face plate interacts with different frequencies. The front usually favours higher frequencies, while the back tends to vibrate when coming in contact with lower frequencies. The two plates balance out these two frequency ranges into a unified sound. This balanced sound defines the overall tone of the guitar.
The way the plates interact with string vibration is called resonance patterns. In other words, sound waves create a pattern on the wood. The job of a luthier is to find the right wood, then mold it into a shape that makes the best pattern possible for the tone desired.
Due to the complexity of measuring the intricacies of these patterns, the science behind the way sound waves interact with the wood inside an acoustic guitar is limited. It is generally accepted that luthiering is far more an art form that utilizes elements of science rather than the other way around. For this reason, it is difficult to scientifically assess the build of an acoustic guitar to determine its quality.
Opinions and judgments are the only real measure and are not quantifiable. It simply cannot be translated into an equation. It all comes down to personal preference and what each person views as a ‘good’ or ‘bad’.
With this in mind and beyond the basic requirement of an acoustic guitar enlarging the sound sufficiently, it is up to each consumer to determine what sounds best. Following your gut instinct is highly encouraged. Word of mouth and help from more experienced guitarists is also invaluable.
Harmonics and Tone
Consider a single musical note played on a guitar. To the ear, it is a singular sound. In reality it is formed of numerous related frequencies vibrating simultaneously to create that specific note. These are called overtones. When they are multiples of the original note played, they are called harmonics.
A guitar string is a coiled bundle of various metals, with a specific weight, girth and tension. This means that any vibration it creates will be imperfect due these real life characteristics, as well as environmental considerations, such as air resistance.
When a string vibration is initiated by a finger or plectrum, the sine-waves created are affected by the fact that the string is held in place on the machine heads and bridge. These points of contact mean it cannot vibrate perfectly: the extremities of the string will alter the shape of the vibration and create harmonics that trail in relation to the core frequency played.
If the wave was viewed mathematically and its full frequency range analyzed, you would note a large peak at the core frequency of the note, and then less pronounced spikes for the overtones. In a perfect world (or using a computer), where the string was free of imperfections and the environment had no impact, you would in theory see one large peak at the core frequency, but nothing else. This would result in an ersatz, artificial and clinical sound.
Conversely, if there are too many harmonic overtones, the guitar would sound boomy and sodden, almost oversaturated with frequencies. The tone of a guitar is, therefore, dictated by how the instrument manages the mixture of these frequencies and how rapidly they audibly subside.
Though it is clearly impossible to notice all frequency-level variations of the tone, the human ear is able to discern overall characteristics. These allow the listener to determine whether the sound is pleasant, overbearing, weak or otherwise. When considering the purchase of a guitar, trust the information provided by your ear.
If you plan to buy an electric guitar, pay heed to the pickups. The acoustic vibrations of non-amplified strings are fairly quiet, making only low volume treble sounds. An amplifier allows the pickup to translate the vibration of the strings into a much louder, amplified output.
The quality of the pickups directly correlates with the properties of the sound produced. Bearing this in mind, it is clear they have a huge impact on the tone produced by a guitar. Scientifically speaking, a well-crafted pickup, with high-grade magnets and meticulously installed internal wiring, invariably leads to a better output.
The placement of a pickup in relation to the strings has a major impact on tone. Similarly, the number of pickups does too. Two pickups will capture the vibrations of the same string in two separate positions to create a unified tone. A pickup near the bridge creates a treble sound while one in proximity to the neck, picks ups lower frequencies.
There exists a variety of pickup types, but they rely on the basic principle of the two most common, described below:
Single-coil is a classic pickup with a crisp tone and brighter properties. It defines the sound of the most famous guitars and artists the world over. It is the single most important factor in the birth of the electric guitar.
Back in the 1930s luthier experimented with various ways to capture musical notes and transform them into an electrical signal that can then be amplified. The most encouraging iteration was the magnetized single-coil pickup. The natural fluctuation of the strings creates variations in the ‘flow’ of the magnetic field. A coil of wires then measures these and in turn creates an electromotive force or current, the embodiment of the string vibrations as a signal.
Though a versatile pickup, the single-coil suffers from electromagnetic pollution issues. Inherent in James Maxwell’s electromagnetism theory, the use of a magnet as well as electricity invariably leads to unwanted residual magnetic waves permeating the sound. A slight hum is perceivable and can become the bane of even the most patient guitarist’s life. In comes the humbucker.
As the name suggests, the humbucker is a novel solution to the bothersome hum of the single-coil pickup. Though techniques differ among manufacturers, the basic principle involves two coils with opposed magnetic poles and wiring. The hum picked up by the two coils then cancels itself out, only allowing the true sound of the vibrating strings to carry through into an electrical signal.
Humbuckers are, therefore, favoured for their cleaner signal, though the tone created is often described as warmer, denser and heavier than single-coil pickups. Hence, why it is favoured by heavy metal and hardcore guitarists.
An understanding of the science behind these two types of pickups is useful when determining what suits your needs.
Internal wiring and Components
Basic electronics require a steady, constant signal to maximize the efficiency of a circuit. The same applies to a guitar.
Due to the relatively low voltage required to power an electric guitar, the quality of the wire used has no effect on the guitar. The important factor is the quality of soldiering work and the components used to transfer the signal from the pickups to the jack output.
By components, we refer to the knobs, switches and selectors that control each pickup. They allow the player to adjust the tone and volume, to switch to or deaden a certain pickup to create a specific sound.
Numerous lower end guitars offer basic models of these components that are prone to malfunctioning. Wires that detach due to shoddy craftsmanship, jack inputs held loosely in place affecting the signal, and unresponsive switchers that fail to turn on pickups, are all common problems. There is a direct link between the cost of the guitar and the quality of the wiring/components. To avoid any issues, be ready to spend a little more.
Guitar hardware is loosely defined as any component other than the internal wiring, components and wood. This includes machine heads, the bridge and the tailpiece. Different types of hardware have varying functions. A correlation exists between a price-tag and quality. Hardware is, therefore, a trustworthy gauge of a guitars overall quality. The reasoning behind this is that better hardware improves tuning precision and keeps strings in tune for longer, notably after temporarily altering their pitch with a tremolo or whammy bar.
Also known as tuning pegs, these vital mechanisms are basically what keeps the strings of a guitar in tune. Mounted on the head, they firmly grip the strings via a protruding metal spindle through which a string is fed then tightly wrapped around. The rotating knobs then allow the player to change the note/tuning by altering the tension of each string. More tension equals a higher pitch and less tension, a lower one. This makes them one of the most important pieces of hardware.
Cheaper models are often temperamental and only keep a tuning for short periods of time, before the player is forced to readjust. Being able to rely on machine heads to do their job should be a prime consideration for a beginner and a virtuoso alike.
There are numerous machine head styles. It can therefore be hard to visually identify a quality piece from a mass produced low-end product. The best way to approach this hurdle is to physically play a guitar and note the speed at which it goes out of tune.
Located on the lower part of the guitar, the bridge is designed to stabilize the strings above the fretboard on the neck. The height of the strings then determines the action, covered below, having an important effect on the playability of the guitar.
The strings are either attached on the bridge itself or pass through it and then held in place by a tail piece. The majority of guitars do not have tailpieces. These tend to appear on guitars with tremolo or whammy bars, the tailpiece acting as a movable component that modulates the strings to create unique fluctuations in the sound.
Bridges are also an important component in setting the intonation of a guitar. Intonation is basically finding the optimum position for each string so that notes are in tune with one another, regardless of their position of the fretboard. The intonation naturally shifts over time due to the wood warping. It is important to have a good bridge that allows small adjustments to realign the strings every so often.
Usually made of metal or some form of composite material, the bridge on an electric guitar can be adjusted by screws to either lower or raise its height. Each string is allocated a bit that can be lengthened or shortened with a screw.
Electric guitar strings come with an end ball. The strings are fed through holes in the lower part of the bridge. The end ball then prevents them from slipping through. Once the other end of a string is attached to the machine head, it is held firmly in place.
Though fully adjustable, the bridge has an impact on the playability and general tone of a guitar. Bearing this in mind, a well-crafted and fixed bridge increases the overall quality of a guitar and by extension plays its part in determining the best guitar for your needs.
Acoustic guitar bridges are made up of two components.
The saddle acts much the same as the bridge of an electric and fixes the strings at a desired height above the fretboard. In the past, saddles were made of either ivory or bone. Recent models incorporate plastic due to the lower production cost and its ready availability. The idea here being to provide a smooth surface so as not to damage the strings.
The saddle is fixed into the second component, the tie block, itself fixed to the guitar body. The tie block is where the strings end, each knotted through a hole to secure them to the guitar.
On the vast majority of acoustics, the bridge height cannot be altered. The desired height of the strings is determined during the manufacturing process. Changes can, however, be made by removing thin slices of the saddle. This is a risky job and it is best to simply buy a guitar with the desired height.
Importance of ‘Action’
Action is jargon for the space between the strings and the fretboard. A smaller gap allows the player to press down on the string with more ease. This represents the basic principle of guitar playing and is one of the key points of contact with the instrument. Numerous advanced techniques depend on suitable action.
If the gap is too large, the player spends more time lowering their fingers and exerting more pressure. This leads to sloppy playing as well as lower endurance levels. A playing session is more often than not cut-short prematurely due to high action.
If the action is too low, the strings can interact with the frets and create a buzzing sound that carries through to the amplified sound, be it acoustic or through an amplifier.
Always check the action when searching for a new guitar. Play around and experiment along the length of the fretboard. Make sure it is suitably low to facilitate ease of play, but not enough to create unwanted sounds. Having the perfect action is crucial to a quality guitar.
The attractiveness of a guitar is hotly debated topic that ultimately falls within the realm of subjectivity. A classic guitar with much of the wood’s natural characteristics intact may be beautiful to one player, while deeply ugly to another. An area where there is less space for discussion, is the finish work applied to guitars. We are talking lacquers, shellac and oils, notably their effect on tonal quality.
The finish can be viewed as a protective shell for the wood. Wood is particularly sensitive to moisture, and can expand as well as contract if humidity levels are too high or two low. Finish allows a guitar to acclimatize slowly to different temperatures and environments, thus avoiding rapid and detrimental warping of the wood.
In addition, finishes are also used to add cosmetic flourishes such as sunburst shades or shine to the wood, but also to iron out any imperfections or cover-up blemishes occurring during the wood cutting process.
It is argued by some that tone is affected by the finish. In favour is the argument that the unique sound of the aforementioned Stradivarius violins is linked to the applied finish mixture. A ‘secret’ formula of sugars, porcelain and glass. Others argue otherwise, suggesting that the oil and resin finish was common for the time and that the quality of the violins has more to do with Stradivari’s craftsmanship.
It is widely agreed that excessive use of lacquers or polish can hinder the wood’s vibration on an acoustic guitar. Essentially, the chemicals trap in the wood, limiting its ability to interact with the sound waves created by the strings. If an acoustic has too much cheap finish applied, the sound will reflect this and come across as artificial or muted.
Conversely, electric guitars are not affected by finish and it is purely for textural and cosmetic purposes.
French Polish / Shellac
Originally developed by French furniture makers, the technique is notoriously time-consuming and complex to master. It has a price tag to match. The end result is a guitar with a unique shine, texture and detail to the wood. It is thin and therefore has little impact on the wood’s vibrations, making it an attractive method to acoustic luthiers.
Easy to apply, durable, cheap and readily available, polyurethane is favoured by large scale guitar manufacturers. It imbues the wood with a shimmering quality that can take on an almost plastic appearance. The downside is that over time it deteriorates and is susceptible to marks and scratches.
A classic finishing technique that is highly praised for its durability and the ease with which it can be manipulated to create unique looking guitars. The finish is gloss-like and ages well. Unfortunately, the substance is highly toxic and represents a real risk for those tasked with applying it.
Guitar Necks and the Hunt for Sustain
Set Neck: The neck is cut to mount snugly onto the body of the guitar and then fixed together with heavy-duty and durable wood glue. While the glue dries, the neck and body are clamped together to minimize movement and ensure a seamless fit. The overwhelming majority of acoustic guitars are built this way and many electric guitars as well. The technique is favoured for its stability, playability and the long-held belief that it offers decent sustain. Set neck guitars are difficult to repair due to the glue.
Neck-Through: Neck-through guitars see the neck and body shaped from the very same piece of wood. Special joints allow the neck to fix itself to the body along the length of the guitar, hence the name. For this reason, no glue or bolts are used. This technique is prized for its stability and is lauded as producing the best sustain possible. Repairs are extremely difficult due to the nature of the build.
Bolt-On Neck: As the name suggests, the neck is attached onto the end of the body of the guitar with the use of bolts, screws or recessed joints. Relatively cheap to manufacture and very easy to repair, bolt-on necks are known to produce the least amount of sustain among the various neck joint techniques.
As mentioned above, it is widely accepted among guitarists and luthiers that neck-through guitars offer better sustain, with set-necks coming in a close second, and finally at the bottom of the pile, bolt-on necks.
A study conducted by scientist and luthier R.M. Mottola (‘Sustain and Electric Guitar Neck Joint Type’, American Lutherie , 2007) suggests otherwise. For his experiment he built a basic neck-through guitar and recorded samples. He then removed the neck, replaced it with bolts and once again recorded. Finally, he removed the bolts and glued the neck on to replicate the technique used on set neck guitars.
From the three samples, he analyzed the data and established that, contrary to conventional wisdom, the bolt-on had the longest sustain pattern. Though the divergence between the three set ups was small, there was a clear difference that surprisingly put neck-through at the bottom of the list.
Unfortunately, no studies exploring stability and tension/stress exist, so we are unable to accurately determine which neck type is best in this context, though the general consensus is that neck-through comes out on top.
Neck and Cost
In general, bolt-ons are far cheaper than their counterparts and from the study above we can establish that the jointing technique has no detrimental effect on sustain. If anything, it improves it. A good tip when searching for a guitar is to therefore be open to bolt-ons rather than immediately veering towards the much pricier neck-through models.
Purchasing a guitar invariably involves a financial consideration. There are guitars available for those with the most thrifty of budgets, all the way to those with sizeable amounts of disposable income. Ultimately, buying a guitar within your budget will be the biggest factor.
Basic economic and financial responsibility dictates that a consumer only spend within their budget. This is particularly apt when it comes to guitars where the temptation to overspend is strong. It is a slippery slope and no player wants to lumber down to their local pawn shop to offload their most recent purchase.
The Science of Tone
By this point, you understand the ubiquitous nature of tone and the huge part in plays in determining the best guitar. What we’ve learned is that natural elements such as the wood and finish have an impact. However, to scientifically quantify tone, we only have limited usable indicators such as decibels, frequencies and compression waves. These can provide numeral value and determine trends, but fail to settle the matter of what good tone looks or sounds like.
In essence, an absence of scientific certainty defines the search for the perfect tone. Instead, the main factor is much more human. Embroiled in the tone debate are many cultural and historical factors that have very little to do with science.
The most prominent is nostalgia and a longing for the good-old-days of the first guitar makers, notably the advent of electric guitars in the second half of the twenty century. Certain guitars from this era have a mythical status that comes down to an emotional response to their sound and the memories associated with it.
Basically, the interpretation of good tone is a subjective matter that differs greatly from person to person. As mentioned previously, this all comes down to the human ear and the way it perceives sound, or more precisely how the brain processes the sound. This process varies depending on a person’s musical upbringing, their mood or even the environmental factors at play during the listening experience.
Tone therefore takes on an almost ethereal quality that lends itself to the way it has become such a focal point in the guitar industry. In a sense, this obsession with tone is an artificial construct. A kind of self-fulfilling prophecy propagated by players and guitar manufacturers alike to sell guitars and assign them an otherworldly quality.
The only overarching quantifiable trend seems to be a correlation between tone and a sound that most mimics the human voice. We naturally gravitate towards what sounds the most natural, relatable and familiar. This is part of the human instinct for consistency and the never-ending search for meaning in a world we only partially understand.
This prompts the question of what defines a comforting or natural sound and can it be translated into an equation by science? If so, would the equation match up with what is universally agreed to be a wonderful guitar with an extraordinary tone? Probably not.
The Importance of Setup
From the points raised above, it is clear that numerous factors affect the quality, but more importantly the playability of a guitar. A good setup is able to unify all these elements into a well-oiled machine that is enjoyable to play.
Think of it as a car tuneup. Regardless of how expensive or good the car is, it will necessitate some fine tuning to get it into optimal condition. The same applies to guitars.
A basic setup checks the relief in the neck, fixes any issues with the action and intonation, and tightens up any of the fixings such as the machine head or a loose jack socket. This means that a tired looking secondhand guitar is likely to come to life after being setup properly. Don’t discount older models as they may be hiding a second lease of life.
It is important to buy a guitar that will motivate a player to spend time honing their skills. The science of motivation is linked to the release of dopamine in the brain. Picking up an instrument you are proud of will invariably make you feel good. Guitar playing is about enjoyment so though science plays its part, it ultimately comes down to personal preference.
Avoid bias before you even set foot inside a music shop. Be critical, but always settle on a guitar that resonates with you. The more emotional attachment one has to an instrument, the more motivation they will have to pick it up and play.
Consider all the factors listed above, yet remember to choose a guitar that jumps out at you. This will keep those dopamine hits coming and in parallel ensure you become a better guitarist.
A scientific approach to choosing the best guitar is a useful tool to understanding what factors determine a good guitar. However, the guitar remains an instrument with a rich history and a certain mysticism. Tapping into that undefinable, emotional quality also plays its part in finding the best guitar.
Personal preference when it comes to aesthetic appeal or tone is so subjective that it cannot be explained or analyzed by science. A young person inspired to learn the guitar is a powerful force and even the most basic guitar will put them in good stead, giving them a suitable tool to hone their skills.
Beyond ensuring the guitar is well crafted, within your budget, and meets the requirements of the style of music you hope to play, trust your instincts and if it sounds good, go for it.
To conclude, there is no such thing as an agreed upon, universally recognized, best guitar. Finding it is impossible, but the above points should help you take a more critical, science-backed decision. You will now have a firm grasp on the ins and outs of the instrument, and understand how all the parts work together to make one of the coolest instruments out there.