Quality In Depth
Building electric guitars is a process that requires craftsmanship and deep knowledge on various subjects. When it comes into building a good electric guitar, there are many details that have to be encountered and analyzed. A guitar builder has to translate the feel and musicality of a guitar into numbers. All these parameters must be optimized and if it is done correctly, the guitar will succeed its purpose. Electric guitars should not simply provide a nice tone. They should inspire musicians into creating art.
But what are these parameters and how do they effect the guitar's quality? Let's dive into the science of tone, sustain, vibration and intonation. Let's see what makes some guitars feel and sound so good when played..
First of all, we should define quality. We all need guitars that look good, feel and sound good. And we all know that one guitar is simply not enough for every musical style. So we should start by addressing the musical "area" that a guitar is going to fulfill. This would create a path concerning pickup configuration, design, and hardware selection. In BMC we have chosen to use the best parts. Except that, we have used our models in live situations for at least two years before their official presentation. We have optimized our geometries, pickup selection, nut materials, tuners, bridges and tonewood combinations. We wanted to be sure that each of our model is going to be the perfect choice in regard to the musical style that is made to serve.
Although instrument evaluation is subjective, in BMC we believe that there are lot of objective parameters that lead to quality made instruments. Let's investigate how vibration of natural bodies works, what the ADSR curve is, how can we make every chord sound in-tune, and how shape affects the tone of the instrument.
About Vibration
Have you ever wondered why our voices sound different even when we sing at the same pitch? Have you ever noticed that some guitars vibrate more than others? Have you ever played a bolt-on guitar that sustained more than a neck-through one? Don't worry, you are not the only one, we have been there. Although people tend to rationalize the answers to such kind of questions, there is a science based explanation that lies beneath. Vibration is the basis of good tone. If a guitar vibrates a lot when played unplugged, it is going to sustain and sound good even when plugged and played on the amp.
When strum, guitar produces a complex frequency response which is called timbre. Timbre is the vibrational result of the interaction between the strings' vibration and the guitar's vibrational profile. Each guitar has a unique vibrational profile. It is an amount of natural frequencies where the guitar "wants" to vibrate more. Natural frequency values depend on the material and the shape of the guitar.
So when a string is plucked it drives the guitar into a complex interactional vibration. If a string driving frequency (and its harmonics) is close to a guitar's natural frequency, we observe high amplitude vibration at this frequency. For each natural frequency we have a modal shape. It is a pattern that indicates the displacement areas of this vibration. If guitar's natural frequency values get far from the string vibration frequencies then we get low amplitude vibrations.
When a guitar is tuned to a specific key we know which are going to be the driving frequencies (musical note fundamentals and their harmonics). So vibrational result is clearly dependent on the natural frequency profile of our construction, which as we mentioned before, is depended on the guitar's shape and material. Vibration gets better when our timbre gets more complex. And this happens when the range of the natural frequencies is close into the range of the frequencies of the notes of our tuning. So, sustain is not only about the way a neck is attached onto the body. It is also about the shape of the body itself and the wood type that it is made of.
The way timbre is structured makes our voices sound different, even if we sing at the same pitch. It makes different musical instruments sound the way they do and it is the reason for different tonewoods to "retain" specific auditable properties. But is there a way to manage the vibrational profile in a way that favors the vibrational result of our guitar?
BMC Navigator FEM Frequency Simulation
Until the recent increase of the computer microprocessor power there was no way to get results concerning the vibrational profile of natural bodies on designing level. Scientists are able to identify the natural frequencies of a guitar in a laboratory environment, but it can only be done after the guitar is built. BMC has invested an enormous amount of time and effort to select the tonewoods for the BMC guitar models. Using Finite Element method, we have analyzed the material properties of woods and we have made the best selections for our body and neck shapes. Will these selections be the best choice for guitars with different shape? No, they won't. In fact each shape has to be analyzed from scratch.
About Pickups
Having set the basis of our tone with the right selection of tonewoods, there is a new world that is introduced when we need to amplify our guitar. We need to recreate our timbre as an electrical signal and this task belongs to the pickups.
A pickup detects all "information" of this complex timbre, found on the string, and translates it into an electrical signal using a coil and a magnetic field. Although most people try to explain the amount of output using the RDC value, this is not exact and should be avoided. A pickup is an RLC circuit. It has a resonant frequency and a Q factor. It recreates our "tone" but it applies an EQ curve on top of it. In addition, the values of each of these factors (Flux, Resistor, Inductance, Capacitance, and rest of electrics) are responsible of the tonal attributes that we are going to experience.
In BMC we wound our pickups in house. We may also use other manufacturers' pickups (upon request). One of our favorite is GAS Pickups (Athens, Greece). Magnet type, coil wire and the construction method have been selected for best performance. Our pickups provide the right amount of attack, excellent string separation and the resonant peak is right at the sweet spot of the most pristine tone experience.
About Tuning
Have you ever noticed that, even on freshly intonated guitars, some chords sound out of tune? Have you ever had the experience of sharp intervals at the first three frets? We know you have and don't worry, it is not your instrument's construction defect. As a matter of fact it is designed to be this way. This is the nature of equal temperament. It had to be this way because we all want to play songs on different keys.
But why does this happen?
Pythagoras (ancient Greek philosopher, 580 BC) was the first to introduce vibrating string divisions. He divided the vibrating string length into specific fractions and provided the wave lengths that later turned to be the basis of the musical intervals of western music culture. Classical composers used to tune pianos to specific keys depending on the composition's requirement. Within the tuned scale, every interval sounded perfectly in-tune due to the correct wavelength subdivisions. This perfect way to divide the octave was completely useless if the composer wanted to perform key transportations. So the rule of twelve (12 semitones), which later got known as the Equal Temperament, became a very friendly way to tune musical instruments.
All today's guitars are designed under the rules of the equal temperament. This allows key transportations, without the need to re-tune. The disadvantage of this way of octave division is that all intervals (except the octave) are slightly out of tune. This can be easily experienced when playing a D major chord on the 5th fret position (Standard E tuning). You can also be annoyed from chords that engage open strings and this will get worse as you get closer to the fretboard end. You may also experience sharp intervals at the first three frets. These are all some of the tuning faults we get from fretted stringed instruments that follow the equal temperament design.
There are several temperaments that we could use to tune an instrument but all of them fix something and damage something else. In the image above we can see some of the tuning temperaments and their differences concerning notes' fundamental frequencies.
Luckily, for all lovers of electric guitars there have been some innovating solutions concerning tuning. BMC is proud to have implemented the Buzz Feiten Tuning System on its guitars models. So, what is it and how it affects our intonation experience?
The Buzz Feiten Tuning system is a combination of construction and tuning/intonating alterations. BMC guitars feature a nut displacement. Our guitars also leave our workshop intonated under the Buzz Feiten principles. Just use a BFTS compatible tuner to tune and that's all.
Perfect sounding chords in all positions. No sharp intervals at the first three frets. Extremely pleasing and sweet sounding tunes on every fretboard position. You will get a unique and addictive intonation experience. For us, there is no turning back. Just try it ..
About Fretboard Radius
You really want a 7.25 fretboard radius to hit the vintage feel. Have you heard this before? We have and there is some true in it. But we have a different perspective concerning our builds.
Fretboard radius is a big subject. We all know 7.25" , 9.5" , 10" , 12" , 16" and even flatter fretboard radiuses. We have also learned that vintage instruments usually have bigger fretboard curvature and modern ones should go for 16" or more. We have also experienced better string action without buzzing, as we go flatter (bigger radiuses). And all these are true. But let's investigate the geometry principles behind it.
Strings get wider as we go from the nut to the bridge. They also follow a curvature (string radius) and finally, strings surface is angular to the fretboard surface. So we have two conical (not cylindrical) surfaces placed under specific angularity in the 3d space. Can you see why matching strings' radius value to the fretboard radius value would be a mistake? We need the string radius to be the same with the fretboard radius on every fret section and this cannot be done if the designed radiuses have the same value due to their angular position in space.
And as we mentioned before, these surfaces are conical due to the widening geometry of the fretboard. It is a really complex problem to solve but we have manage to perform our calculations.
BMC fretboards are Compound. The fretboard radius changes as we go from the nut to the fretboard end. The amount of this transition is calculated in respect to the strings' surface characteristics. For example, a compound radius fretboard that goes to a guitar with a locking tremolo (16" radius at the bridge and 10" radius at the nut) is different and unique.
Every BMC model has a calculated compound radius fretboard which provides the best possible buzz-free string action. We understand and respect musicians who favor specific fixed radius fretboards, but we have something better to offer. It is our belief that low action is crucial when playability is concerned and compound fretboards allow us go lower.
About Blind Fret slots
There are more than one ways to open the fret slots. Traditional luthiers have been using jigs and a thin saw to open the slots. Guitar factories who need to do it fast, use machines with several blades that cut all frets at once. BMC uses CNC technology for neck cuts. Fret slot cutting is a crucial procedure and has to be precise. All BMC guitars feature blind fret slots. They don't just look good. Blind fret slots add to the neck stability.
Using Simulation methods we have been able to identify stress concentration in our constructions. The wood material left intact, found close at the fretboard sides, acts as a stiffener. It adds strength to the fretboard.
In addition, we like using CNC for such delicate cuts. It is obvious that a machine capable to move within steps of 0.03 mm, will perform fret slot cutting more accurately, comparing to the traditional methods. The repeatability of CNC machines also assures that these great cutting results will be done the same way on every fretboard, each time we cut.
About Frets
Frets affect tone and playability. Our experience with different fret materials and sizes has made clear that the best frets for our instruments are Stainless Steel frets. Although stainless frets are labor intensive and provide faster tool wear, their qualities concerning musicians' perspective are incomparable. Bendings are effortless, frets will never get dents and they will never loose their shine. Tonewise they favor higher harmonics more than conventional frets do but don't worry, the guitar tone will not be altered that much.
We aim to build consistent instruments and stainless steel frets help to this direction. All BMC guitars leave our workshop with leveled, re-crowned and polished stainless steel frets.
About Bolt-on Necks
There is a skeptical attitude against bolt-on necks. People tend towards the belief that these kind of constructions lack stability. There is more going on here. In BMC we strongly support that bolt-on guitars can be as stable as set-neck guitars, but it has to be done the right way. We need to avoid wood screws if we really want a tight fit. BMC uses brass inserts into guitar necks and conventional M5 stainless steel screws to tighten them up. In this way we can go further on tightening without the fear of damaging our precious tonewood. Our necks stay stable into the neck pocket. We retain the ability to change our necks (in case of damaging) without sacrificing the pros of the set neck guitars.
About CNCs and Craftsmanship
The debate of the use of CNC machines vs the Hand Craftsmanship in not new. There are people who believe in the use of new technologies and others who like to know that their instrument is totally made by hand. Both perspectives are respected from us. We understand both. We believe in fact that best results come with the use of both.
Guitar building includes several procedures which require different approach. We use CNCs for the basic cutting of our bodies, necks and pickguards. For us, using CNC technology is the best way to get accurate parts that are exactly the same each time we cut.
All other building procedure is done by hand. Sanding, finish preparation, spray-painting, buffing, frets and nut installation, nut slotting, assembling, setup and intonation. You shouldn't use machines to spray a sunburst finish, it is art. And you shouldn't carve your 3D geometries by hand if you want them to be the same every time.
About Finishes
Getting a high gloss finish that resembles expensive automotive looks is a process that requires the right equipment and a lot of experience. In addition, every finishing compound product has its own characteristics, mechanical and physical properties and getting the right one is a tough way to experience. Within the years of BMC guitars development we have found our way to finishing. We have chosen our materials and have optimized our procedure.
It is often said that Nitrocellulose lacquer is the right way to go due its natural aging character. Some people choose finishes that let the wood "breathe". It is also said that tone diminishes as finishing layers get thicker.
There are a lot going with finishes. We need a tough finish that doesn't get scratched easily. We need it to be as clear and glossy as possible. Its viscosity has to provide a problem free usage. It has to cure fast enough and finally, its mechanical properties have to cooperate with our guitar's tonal character.
In BMC we use acrylic urethane for wood sealing and acrylic/polyester resin compounds for clear coating. There is no worry concerning our instruments' tone. It is all there. Our method and finishing materials do not decrease our guitars' resonance. They only provide a great look that goes together with our beautiful sounding instruments. Our colors and wood figure pop out without the fear of cracking or peeling off during the years.
