The resonator Block in action:
As an introduction I think it might be a good idea to first see what the resonator block is and what it does. In this video you can see the resonator block in action. The wood resonates with the strings, you can also see that different notes make different parts of the resonator block resonate. The deformations are real, the slow motion effect occurs because of the framerate of the camera (25 fr/s), this gives it a ‘stroboscopic slow motion effect’.
The resonator block
‘Wood that Resonates with the Strings’
Just like on an acoustic bass, the bridge of my eub-design rests on a ‘resonant piece of wood’. On an acoustic bass this ‘resonant piece of wood’ is the large body, on my eub the ‘resonant piece of wood’ is the compact resonator block.
The body of an acoustic bass needs to have a (very) large surface, because it is designed to make the air vibrate so you can hear it, acoustically.
My eub’s body -the wooden resonator block– is designed to resonate with the same characteristic spectrum as the acoustic bass’ body does, but without the large surface you need to make the air vibrate. Because you don’t need the air to vibrate; it’s an electric bass. This means that when not plugged in and amplified, it has about the same volume as an unplugged electric bass guitar.
Just like with the pickups that generate the electric signal on an acoustic bass, the pickups on my eub are placed between bridge and the vibrating wooden body. This ensures an ideal balance between direct string sound and the lively richness of resonating wood.
Violin plate tuning, ‘Chladni method’
Violin Family Character
When a professional luthier builds an acoustic bass by hand, the crucial work is the tuning of the top, and to a lesser extend, the back plate of the body. By carefully tuning these plates, the luthier is able to build in the desired resonances that together form the tonal response, the character of the instrument. There are many different resonance patterns possible in a violin plate, and these can -to some extend- be tuned.
In the picture I have a violin top plate (without bass bar) that is sprinkled with tea leaves. When the topplate is set into motion by a loudspeaker on a constant tone, a pattern such as this, called a Chladni pattern after Ernst Chladni 1756-1827, emerges. The pattern depends on the tone. Just like a string harmonic with nodes, but one dimension higher (2.5d); at some places (nodal lines) the plate does not move, so that’s where the tea leaves collect.
In a violin plate, altering the thickness and curvature of the plate to change one single resonance pattern, can effect all other resonance patterns. this makes it very difficult, if not impossible, to tune the resonance frequencies individually. On the resonator block, the layering of individually tuned wooden plates gives me a lot more freedom and control to tune in specific individual resonances. This means I am able to work towards the character I want, in my case the much sought after lively, rich, articulate, balanced tone with a touch of ‘dark raspy roughness’; or, from another perspective, the characteristics of a member of the violin family.
Woodhouse theory on periodic deformations in the bridge
The inspiration for this idea of the resonator block came to me when several paths collided.
On the one hand I was inspired by theoretical research on stringed instruments. There’s the work of Carleen Hutchins, and Neville Horner Fletcher and Thomas D. Rossing’s excellent work The Physics of Musical Instruments, but also newer insights offered by academic research on violins at -among others- KTH Royal Institute of Technology in Sweden and at the University of Cambridge.
I’ve done my own research also; played around with prototypes which I measured with the Chladni Method to see what happens when specific variables are changed, later I used FFT spectrum analysis software. And also always my ears of course.
As a reference, the resonance spectrum of a Dallinger bass (1804)
One of my own FFT analysis plots (not definitive)
Viola d’Amore by Vogelsangs
So, on the one hand inspiration came from scientific research.
On the other hand it came from an historic instrument. Back in around 2000 my collegue luthiers Willem van Griensven and Sjef Vogelsangs who I join every now and then, had plans for building a Baroque instrument, a viola d’amore (and they did build it). A viola d’amore is a quite big ‘violin’ with 14 strings. Seven strings are playable, the other seven are so called ‘sympathetic strings’; the player does not touch these strings, they vibrate along with the strings that are played. Therefore they run through the neck of the instrument, underneith the fingerboard. The sound of this instrument is amazing, it’s a ‘singing’ violin.
Now I am quite a slow thinker, these different paths of knowledge (scientific theory and knowing about the viola d’amore’) existed as parallel for a quite some time before they actually connected …
The two level bridge of a Viola d’Amore by Vogelsangs
Below the playing strings are the seven sympathetic strings; essentially very compact resonators that can be tuned to precise pitches which together cover a broader spectrum
The ‘flash of insight’ question that connected the two;
Is it possible to build a compact wooden resonator to represent the body?
The short answer to this question; yes, as far as my theoretic knowledge reaches, this should be possible, in theory. In my naivity I sincerely thought it would take me about 2 weeks to develop this idea into a design. In practice it became a huge engineering challenge, it took me more than ten years to develop this eub. These ten years existed of piling up different perspectives, probing dead ends; a mixture of progress and inestimable chaos.
Although the graph of the Dallinger bass above suggests it, there is no ‘formula’, just like travelling a river upstream to see what it’s made of, you’ll end up with all kinds of different places and mechanisms that aren’t ‘a river’, but which are necessary for the river to exist as it is. During all these years theoretic knowledge gave me the confidence to keep digging.
Research: raw version of the resonator block
The first prototypes of the resonator block I made were built out of wooden sticks, their elongated shape as a remnant of the strings idea of the viola d’amore.
Although this theoretical ‘stick’ solution was the most obvious (to me) and some of these prototypes looked promising, the sound itself wasn’t ‘complete’ and the fragility of the thin sticks made me leave the concept; a classical ‘kill your darlings’.
Knowing how to in theory is not the same as being able to. It’s like someone saying “well, here’s a grand piano, low notes on the left, high notes on the right, here’s the score; now play!”: The layering itself gives more control, but as I found out the hard way, tuning is definitely a matter of experience and skill.
A ‘wooden sticks’ version of the resonator block
Another peak into the past…
… Because underneith the surface of experience, skill and control, exists a world of trial and error ‘we consumers’ usually do not see. Like with experienced dancers or TV-cooks, it’s the illusion of ease and souplesse where training and discipline rule.
The bass with the sticks in the picture on the right here is just one of the steps inbetween. With a whole range of these steps, the resonator block slowly evolved into the current design; the top-layer with tuning weights and below that the coupled plates in the resonator block.
So, finaly I developed a method! From the general theory in formulas and inspired by the viola d’amore, I came up with a specific idea about the shape, the basic architecture, the framework. Layering (superposition) does indeed give me more control over the individual resonance frequencies. Still very theoretical though, but now I could at least play with bandwidths and reverberation-time, and build towards the complex desired response of a master instrument step by step, however… This was only the how dimension, the other -parallel- dimension of the design is the what; what character do I actually want to tune in?
Psychoacoustics is the science that concerns itself with the quality of sound; of what sort is it, how do we experience sound, how is it nested in culture, what qualities do we consider good in a bass etc. In the past few centuries, the acoustic bass has evolved and the bass(es) we know right now ‘won the evolution’, for now. The acoustic bass as we know it has nested, anchored itself into the (Western) collectively shared network of ‘truth’.
As the designer of this eub, I lean on both the cultural and the neutral understanding of quality. The cultural understanding being that what I consider part of ‘tradition’, and what I expect to evolve over time, the neutral understanding being that what I do not expect to evolve, like calculation methods of resonances (‘hard science’) and the practical knowledge like ‘if I shave off wood here an add a weight there, this will happen to the color of the tone’.
While reading scientific papers they seem so logical and watertight, I tend to forget scientific theories are abstract generalisations of reality and that they are intended to be true independent of time and place. Once back in the workplace standing there with a piece of wood an a chisel in my hand, I am reminded that the theories represent a parallel ‘paper’ world; a deceptive degree of generality that does not match the contingencies and interpretations in ‘real life situations’. In ‘real life situations’ I misjudge and make mistakes, while I generate my own story, while my own style grows. I guess this discrepancy between theory and practice is recognised in many professional fields, from healthcare to law to education to … Science is not only descriptive hindsight, while boiling knowledge down to its scientific essence in order to convey it tot the next generation, the most important knowledge – experience – is often lost.
So, the spectrum graphs that describe the tone of some bass -as depicted above- indeed look very ‘scientific’, while a fair question is; how scientific is it, and how useful is it, if at all?
I’ve also noticed that some who see a formula or a spectrum graph, are put off by that ‘scientific approach’. They associate ‘scientific’ with terms like ‘soul-less’ or ‘sterile’ and ‘lifeless’; rational. And they have a point; the extracted theory on the factors that influence the response of the instrument are hard science and this can come across as dry and exact, it is quite far from the romantic idea of the craftsman in his workplace filled with wood shavings. On the other hand…</ br>
Chet Baker. Real playing is a state of mind (image source)
A state of mind
Personally I like to think of knowledge and skill as the foundation for the unexplored paths a creative pioneer investigates. It is like jazz musicians who can play freely because the skill, knowledge and experience allow them to go anywhere their imagination leads them to. The years of training provide them with a vocabulary and grammar with which they can express themselves. And then playing freely is beyond control, it is not rational, it’s a state of mind. Some would say it’s a spiritual experience, I prefer terms like focus and flow, there’s an element of ease, one sound naturally leads to the next while you’re mind is really clear, expression in sync with emotion; you’re letting stuff emerge. Definitely not soul-less, definitely not a product of ratio. Mindfulness, or mindlessness?
Someone holding a trumpet for the first time can also claim to play freely and blur out random notes, but can not play anything he/she wants, so to me that is not free at all; to me this relates to terms like opportunistic, superficial, cosmetic, paper thin, fake, indifferent; it doesn’t show commitment, responsibility or investment. I’m not saying opportunism is ‘wrong’ in the sense of having a malicious agenda, it’s more like the difference between being friendly and being a friend. There’s no ‘substance’ when more in depth knowlegde and experience are missing.
There’s the path of the hard science, physics, and the path of ever evolving cultural taste, and where they meet the pioneering of the boundaries of instrument design is found, this is where life florishes. Soul-less, sterile, lifeless? I don’t think so. On the contrary, I think gaining knowledge, gaining new insights and skills with confidence, is necessary for traditions to evolve.
Real playing is serious business. An authentic style grows and should be a result, not something you ‘apply’ (copy-paste). At least, that’s my personal opinion. During the process of designing all kinds of choices are made which inevitably divert the path from general scientific knowledge to new paths and a certain style. In my eub this is what I stand for. My style. So I’m not going tell you my eub is ‘the best’. I’m not going to tell you you should buy my eub. I make what I personally, after many years of gaining knowledge, of gaining experience, of experimenting, think is best. Maybe you’re among the ones who happen to like it, but if you’re not, I advice you not to buy my eub (indeed, a career in marketing was never really meant for me).
There are two majorly important aspects of identification of a musical instrument. The first one is the timbre, the ‘color’ of the sound. This is how the available energy is ‘smeared out’ over the tonal spectrum (bassy, dull, warm, bright, sharp..). The second aspect is how the tone varies over time (envelope), how the available energy is ‘smeared out’ over time. These factors also determine if the the bass is easy to play; you don’t want that hard-work flat strangulated squeezed voice, but an open tone, alive, responsive, dynamic, breathing, resonant: ‘headroom’ in terms of volume-dynamics.
In the top layer with the tuning weights and the resonator block, I can regulate the energy-dissipation over time; on solidbody e-basses the energy dissipation is much more evened out over time than on acoustic basses. You can hear that difference clearly if you listen closely. You could say the resonator uses up the energy by vibrating. Solidbody e-basses are usually built very stiff, so the energy dissipation is spread over a longer time.
What pizzicato players may want to hear; ‘regulate the energy-dissipation over time and tonal spectrum’ also means, that I’ve made an effort to tune in a modest but effective bouncy ‘boom’-suspension that is not just some random superficial ‘plok-sound’ or loud sub-burst, but a tuned spring-like boom, out of which the tone emerges, settles.
Strings do not stop at the bridge
The layered wooden plates and the strings exchange energy between each other, until it fades out. This gives a slight, natural reverberation, just like the acoustic bass does.
This reverb-effect is also there, because the strings do not stop at the bridge in a rigidly fixed bass guitar style bridge. This ‘non-fixed’ construction where the bridge is held down by string force while the bridge rests on what is essentially a spring, makes it all relative and ‘floating’. Now it is possible for energy of the played string to ‘bleed’ into the other not played strings. These other strings will then – just like the sympathetic strings on a viola d’amore – resonate. This is what happens on acoustic basses also, it is a real ingredient of the sound spectrum of acoustic double basses. You might think these sympathetic strings do not vibrate enough to hear a difference… even if this were true (which it isn’t), the point is, it steals energy:
One of the lessons of all these years of research is, that a substantial portion of the energy that is put in by playing, is not generating sound. This ‘loss’ is actually what shapes the sound. Like the chips of stone are the loss of a sculptor.
But what makes acoustic stringed instrument design really interesting to me (and extremely complex), is that the there’s an interaction. The energy does not just cascade through the instrument in one direction from A to B, the resonating parts exchange energy back and forth, because they are springs. While the energy travels through the intrument until the tone dies out, the vibrant instrument ‘lives’.
Another key demand in the design, is that it should be ‘compact’. In a way you could say the resonator block has quite al large surface, but it is folded up. A folded up sail does not catch as much wind, is the idea:
Just like with a sailboat with a big or a small sail; of all available energy radiated by the speaker, the small surface of the resonator block simply catches ‘less wind’, compared to the huge surface of the acoustic bass’ body.
Add to that that the layering of wooden plates provides a ‘sound shadow’, like a sailboat that steals wind from the boat in its ‘wind-shadow’.
Using the resonator block, chances of feedback are significantly reduced.