In this post I discuss some aspects of the design of the headstock of my upright bass.
As you can see, I have chosen quite a traditional headstock with pegbox and scroll design. This might seem a bit odd at first. Because when designing an electric upright bass from scratch with absolute freedom, ‘carte blanche’ as it comes to the shape of the headstock, this is probably the least innovative idea… And moreover, when assumed that low weight and compact size are some of the major design axioms for an electric upright bass, why would you make a headstock with pegbox and scroll at all, why not a headless bass like for instance Steinberger or Washburn Mark King bass guitars?
Well, the first part of the answer is quite simple; a headless neck is still a rather experimental path of design for 3/4 upright bass. This means you severely sacrifice the freedom to choose strings specifically designed for acoustic upright basses.
Upright bass string with silk winding at both ends
Together with a choice for the tailpiece, the standard ¾ string length gives the prerequisite of string length above the top nut, and therefore more or less a given (remaining) distance from top nut to the tuner peg for each string. At the headstock end, acoustic upright bass strings are often thinner. This allows easier winding around the pegs (usually wound with a material like silk). So there is also a minimum required length above the top nut.
Conclusion; the string choice together with the tailpiece, dictate the positions of the tuners and so dictate the boundary conditions of the headstock design.
While I easily dismissed the headless neck with rational reasoning (limited string choice), I can’t dismiss the bass guitar style headstock so easily; actually it can probably even be made smaller and lighter than the acoustic double bass style pegbox design.
Generally I am blessed to find myself in the comfortable position that my personal taste aligns with ratio, so that ratio can be used to justify certain design choices. But as it comes to the headstock, a strange glitch in my brain takes over; while I have no problem furiously redesigning the whole intrument and turning every stone to find the optimal lightweight solution, the headstock somehow doesn’t allow me to do that, like magnet poles repelling: every ‘improvement’ disproportionally substracts from the beauty of the archetypal shape.
The instigator of this glitch is an inspirational history teacher (mr Kwak), ever since this lesson, I have a weak spot for the scroll:
In ancient Greece, they built most houses from wood. Using wood for a column introduces a problem; the top end of the columns gets exposed to sun and rain, so the end grain has the tendency to crack, tear and rot. This of course weakens the structure. So the Greek sealed the top of the column with leather slabs as a raincoat. The excess overhanging leather would then curl up into a scroll. The stone scrolls of Ionic columns are an abstract artistic interpretation of these leather slabs.
“Ionic” wooden column covered with leather skin to prevent end grain from rotting
Late Renaissance /Baroque violin-family luthiers like Antonio Stradivari (1644 – 1737) and Giuseppe Guarneri (1698 – 1744) recycled the scroll shape. This was an era where not only they ‘rediscovered’ Greek and Roman history, which broadenend the perception and concept of time, but also where expeditions (had) sailed around the world to discover ‘new’ land, where science and mathematics revealed the laws of nature, be it the heliocentric worldview (Galileo Galilei 1564 – 1642) or the microscopic world (Antoni van Leeuwenhoek 1632 – 1723).
For luthiers living there and then, the worldview hugely expanded, in space, in time, and in wealth. I can imagine the infinite mathematical spiral shape of the scroll resonated in such an era where the limits of imagination lay beyond the horizon.
And so this is why I want my bass to have a scroll; passing the art meme as a link in the chain, an ambassador for past and future. Because I like the idea of passing the scroll as an ancient art meme and – not least – I like it aesthetically.
CNC stands for Computer Numerical Control; programmable mechanical machines; robots. You can use a cnc machine to replace some of the handwork. It is like MIDI, complete with a similar discussion on artistic value; you can have a real person playing a live concert on an e-piano, and record a midi file of that. When you play back that midi file on that same e-piano, it is the-same-but-not-the-same as the original. This is – I guess – why musicians have audiences. The audience wants to witness the act of playing (althought this idea is disputed by the recent popularity of virtual concerts where holograms of artists like ABBA fill the stage, while the artists themselves are not present).
I understand the romantic idea that artisan handwork adds value. As it comes to lutherie, I suspect many people imagine, or want-to-believe this romantic scenery of a Geppetto-like crafts(wo)man in a picturesque workshop, where a permanent golden hour sun shines through the diamond grid window, covering pretty much all shades of brown – from the dark shadows behind the purring cat to the bright freshly curled up woodshavings. Perfect for dreamy soft focus photography, this image of what ‘a luthier’ is. The very implication that there could be anything other than handwork going on here introduces a perspective that could break the magic of this cosy nostalgic narrative.
My self designed and pieced together 3 axis cnc portal machine
Panning out and zooming in to the real world however shows a different picture. The making of a headstock by hand actually consists of pencil tracing templates onto a piece of wood and then using (hand)tools to remove the excess wood. The first time-consuming step is to get the tracing exactly in place on a piece of maple. This is tricky to get right because of the wedge shape. Once the contour tracing is in place and roughly cut with the bandsaw, the actual handtool work of the contour is rather simple, but not too simple; it has a meditational quality to it.
The meditational experience I think arises because the mental concentration level is high but steady. As you use very sharp tools to carve away in small increments, you do not overload the mind into stalling. You can just ‘keep up’ so to say, which makes the experience satisfyingly continuous and seamingly effortless. Some would call it flow, or in the zone. I think most musicians will recognise this.
However – and this is the reality check that might disappoint the romantic, for all other operations than carving the contour, the constant checking and marking off of dimensions (symmetry) that gradually increases as work progresses, interrupts this experience of flow. And as you come closer to the deepest surfaces, the interruptions become a plain frustration factor; no flow at all (at least, that is my personal experience).
I find carving out the deepest part of a pegbox bottom not a pleasant chore. I confess I ‘cheated’ with the drillpress the very first time already. Not so much out of impatience, more “there must be a better way to do this”.
Pencil tracing and bandsawing of the headstock contour. The wood is wedged because it is a ‘pie part’ of a tree trunk. The front is wider than the back.
When making a headstock, there is no real interaction with the wood tonewise. It are the dimensions that are leading, the end result is fixed dimensionally, beforehand.
I don’t think the instrument is more valuable if I have three days of frustrating handwork with templates, gouges, chisels etc. When all goes perfectly well I could, with a lot of experience, match the same level of dimensional precision a cnc machine delivers. But I will never outperform it in speed and efficiency.
Another way to see it; a skilled luthier working in series, delivering constant quality on ‘flow-autopilot’, is like a biological cnc machine. Handwork is based on templates that are made in advance, the same set of templates is used for multiple instruments. Instead of a pencil tracing a template, the cnc machine traces a 3d template path. The point is; handwork on a headstock does not make the instrument sound or play better (it would make it a lot more expensive though).
On the other hand, when making the tonal wood parts of the resonating body, the dimensions are contingent on the bending and resonance properties of the wood. This makes handwork – a real person evaluating and steering every step of the process – the superior method. There is a responsibility, but no dimensional outcome to comply to, the procedure forms along the way, through interaction. As a novice I used to measure and control every step; I recorded tapping sounds and did Fourier spectrum analysis. Nowadays I just bend, flex and tap the wood and know from experience when to stop scraping off thickness.
There is concentration and involvement, just like a sailor who reads the elements to define the course, it is never the same and probably never perfect.
Just like handwork, working with cnc is very much a learning process. For the first cnc machine I built – back in the DOS based Windows95 era – I used the guide rails of architect’s drawing table, put some steppermotors on it and wrote code by hand. Since then I have built 3 new machines, each machine a step better. Because I have been working with cnc for so long, experienced the challenges and pitfalls, had my big and small victories, I have grown a passion for it. This is of course a totally different perspective than that of a customer who might expect traditional artisan handwork. The way I see it, working with cnc is a craft of its own, just as carving by hand is.
There is another dimension to cnc machines I would like to promote. Previously I mentioned the experience of flow. I would like to incorporate this state of mind in the processes in my workplace. Luckily, I get a similar state of mind when watching my cnc machine carve out a piece I designed myself. It is like witnessing a live performance. I set up the chain of events in the program. The program unwinds; pressing ENTER kicks the first domino stone, leading to a slow but inevitable reveal.
The deeper concept here, is that there is a clear separation of information (the cnc program), ground material (maple), energy (electricity) and the tool (the CNC machine). It might seem grotesque but bear with me; ever since the birth of the universe, matter, information and energy have been spreading out in an ever ongoing chain of cause and effect. Interacting, arranging and rearranging into different compositions, to after 13 billion years finally meet in my workshop (of all places). Some of it enters as electricity via the wall outlet; some of it comes as the block of maple I carried in myself; there is the CNC machine and… there is this package of information; the program I wrote to harness electricity, cnc machine and maple to form the headstock.
The huge advantage of this seperation of information into a program detached from my brain (and the sharp tools detached from by muscles!), is that the information in the program does not decay or mutate, and you can use it anytime. All the actions that would otherwise be done by hand, are ‘extracted’ to a program. This program defines a very specific chain of events inside my workshop. In other words, I extracted the craftmanship, condensed and redefined it inside the program; the program is a translation of handwork; different language, different grammar. Although I let the cnc machine do its dance and so bypass labour of my brain and hands, it doesn’t feel like cheating at all; there is pride here, of – yes – craftmanship.
A major principle here is, that apparently, the program makes this particular chain of events that produces the headstock, the path of least impedance; it happens because the program is a set of boundary conditions, it impedes other possibilities.
Of all the possible arrangements the laws of nature in the universe allow to happen, carving the headstock was apparently the most likely chain of events to occur. Mind you, this includes the coming into existence of the program, which in itself is a branch of the same majestic 13 billion year old chain of events. Welcome to the frontwave of NOW where you read about these events. All things are delicately connected.
I suspect the steady pace of the cnc machine tracing its path that your mind can just keep up with, also triggers the experience of flow. I would suggest 'flow' is an emergent state of mind based on resonance. Because by definition, resonance occurs where impedance is minimal. Like with the minimal effort of a kid on a swing, it is the efficiency, the relative effortlessness, that is pleasing.
And of course this is closely related to acoustic musical instruments in general; they are in essence resonators with specific boundary conditions, where a small input of energy - a small effort - of the musician, produces specific tone (= a highly ordered cyclic pattern).
Take the flute for example; you blow an undifined FFFF noise over the flute's opening, and out comes a highly ordered content, a clear tone with predictable quality so if you perform the same action, it will result in the same tone. Seemingly effortless.
Designing and making a headstock with a 3-axis cnc machine is not for beginners. Even though I thought I had over the years gained quite a good insight in – and feel for – what the limits of wood and tools were, I still sacrificed an unreasonable amount of mill flutes and pieces of maple while trying to find the optimal program and workflow for this headstock. Challenges like how to get these very narrow tracks inside the scroll so deep without jittering the tool tip or without clogging the track with wood shavings and breaking the mill flute; how to precisely clamp in the workpiece in the cnc machine to mill the other side(s) in slightly tilted angles; this requires a lot of expertise, not to mention trial and error.
In my design, the whole headstock is comprised of 11 different cnc programs, 6 different mill flute types and 5 clamping setups. After all this, it still has to be chiseled at some inner corners and after that sanded and finished.
Headstock CAD design stage
Headstock Contour Milling
I hope that by reading this article, you have come to appreciate and understand my choice for cnc machining the headstock, and understand the benefitial role of cnc machines in the workshop; they excell at repetitive work where precise dimensions are paramount, I find it a welcome innovation.