The idea of  “Cellular Fiddles” has evolved out of two earlier projects. The Dimpled Viola  made a feature of some of the visually interesting rough carving of  a violin that normally get lost in the finished instrument.  The Turtle Fiddle which took one of the visual aspects of the the Dimpled Viola, its rather reptilian looking ribs,  and used that as a design theme.  These two projects scratched at  many underlying ideas and questions including

  • The sources of inspiration for modern violins:  Currently we look backwards and inwards, copying old violins, what if we didn’t limit ourselves and looked elsewhere ?
  • The evocative devices that are common to all arts, whatever medium they are deployed in.
  • The power of abstraction and suggestion to inspire thought in the audience.
  • The qualities of  natural objects that make them attractive to us.
  • The use of camouflage and mimicry in nature  and its similarity to the practice of antiquing instruments.

Completing these two projects was both rewarding and stimulating. It gave me many insights into these questions and raised many more, yet at the end of the process I wondered what I had really made?  The two instruments sound and play like professional quality instruments,  they excite strong reactions but I couldn’t help feeling that they are really all they are is decorated violins.  Then it occurred to me  that if I took and developed some of the elements being used on the Turtle Fiddle, there is the possibility of affecting the sound of the instruments and that would bring these fiddles into a different realm.

Why do this?

The violin has evolved over hundreds of years through trial and error, and through the experience  and insights of many gifted makers, so I think that it is extremely unlikely that I would stumble upon some innovation that would produce a “better” violin. However I do think that by trying different violin designs we can get a deeper insight into how violins function and if we gain that insight,  it may be possible to use it to control the tonal character of our instruments.

Cellular Fiddles

Looking at the exterior structure of the Turtle fiddle what we see is a ridge-and-hollow arrangement, many depressions bounded by ridges. I call each of these similarly shaped  units a “cell”. The idea is to take the cellular structure that I used on the Turtle Fiddle and to push it to extremes to see what the tonal effects might be

The exterior of the Turtle Fiddle showing a repeating pattern of one, or possibly two, roughly similar cell types. In this fiddle the cells are pretty uniform in size and shape, but they don’t have to be.

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Cross sections of the Turtle Fiddle (above) showing the ridges and hollows of the cells. This arrangement is similar to the thin-plate-and-brace construction used by guitar builders (below).

 

 

 

Guitar bracing and its effect on tone

Let’s take a look at guitar bracing and consider why it is a matter of such interest to guitar makers,  and why there are almost as many bracing patterns as there are guitar makers.

The braces were first used to prevent the thin top from collapsing under the forces exerted by the strings, but then it was found that the  size and shape of the braces, plus their distribution on the plate, very much affects the tone of the instrument. This is because all plates, including the plates of stringed instruments, have typical shapes or patterns in which they “like” to vibrate at particular frequencies. They “resonate” at those frequencies and the exact patterns that they form when resonating are determined by the shape of the plate and its mass and stiffness distribution.

Perhaps this is not a very clear explanation, but take a look at this video of a vibrating plate, its not a violin plate but similar things are going on in violin when it is played.  The shapes formed on the vibrating plate are called “Chladni patterns”  The light colored lines are formed by grain scattered on the plate accumulating on the parts of the plate that are not moving. The black areas of the plate are bouncing up and down, with adjacent areas going in opposite directions.  Now  imagine that if you were to glue a stiff piece of wood , or a “brace” across part of the plate, it would disrupt the patterns for that plate. The plate would then have a different set of resonant frequencies and form different patterns associated with them.

Tonal Richness

When a stringed musical instrument plays a note, many different parts of the instrument vibrate at many different resonances at the same time. It is the overlay of many resonances that determine the the tonal color of the instrument, in much the same  way that the flavor of a curry is determined by the choice and balance of the spices used in it.  Since the bracing patterns affect the vibration patterns and resonant frequencies of the plates, it would seem that there is the potential here to shape the sound of an instrument by changing the bracing patterns.

A variety of guitar bracing patterns represent attempts to shape the guitar’s tone and playing qualities. Source: Wikimedia commons

Bracing Possibilities

In guitars, as I’ve mentioned, bracing consists of pieces of spruce glued onto a thin, flat top of more or less even thickness.  Variety comes from the dimension of those braces and their layout.  In the Cellular Fiddles the possibilities are even more various because the “brace” or cell boundaries are carved from a single piece of wood,  thus the wood between the boundaries could be of uniform or varying thickness.  In addition to the variety of cell pattern, the  shape of arch itself can also be varied  and is also known to affect the tone of the instrument.

It should e noted that the braces on a guitar will have a lot more effect on the structure, and probably  also on the tone of the guitar.  This is because the guitar braces are much larger relative to the top, than the ridges on the fiddle.  In addition most guitar braces cross the grain of the top at least a little, which provides a lot more stiffening effect than the carved ridges on the fiddle, which naturally are same-grained.  It may be that the ridges mostly  provide mass,  but mass is important as resonances are defined by their both spring and mass components.

Here are some of the possibilities that occur to me:

Cross sections of different possible “bracing” patterns. 1 – Guitar top with a variety of braces. 2 – Section of the Turtle Fiddle showing a varying thickness between ridges. 3- Top with uniform thickness between ridges. 4 – A variety of thicknesses between ridges. 5 – A composite arch with uniform plate thickness.

 

Contrasting Fiddles

So what pattern to make the cells (or bracing pattern)?   My aim is to do something that will have a noticeable effect on the tone and might shed some light how to manipulate the tone of later instruments.   The place to start seems to be to probe some of the areas that are thought to be most critical to violin tone.  Returning to the Chladni patterns seen in the video above, similar patterns can be formed on the  free top or back plate  of a violin by sprinkling powder  on the plate and and vibrating it with sound from a loudspeaker.  The frequency at which particular patterns form are thought to be indicative of the quality of a violin .  The particular patterns are called modes and the most influential ones, which occur at lower frequencies,  are known as Mode 2, the “X- mode”  and mode 5, the “Ring Mode”.  Most makers are aware of the frequencies that their free plates  vibrate at for the X-mode, you can simply hold the plate up and tap it and see what note it rings at.  It is an easy way to see if you have removed enough wood from the plate or not. Some makers get more sophisticated and look for a relationship of frequencies between the X and Ring-modes and have methods for bringing those modes closer together or further apart.

Chladni patterns on violin plates. The characteristic patterns are known as “modes”. the frequency at which the mode occurs is also known as the  “tap-tone” for that mode. Source: platetuning.org

It seems to me that if I was to make a violin that had a cell pattern that aligned with the X-mode it would have less inhibiting effect on that mode  than a cell pattern that crossed the lines of the modal pattern.  My idea is to make two violins one, with a X-type pattern and one with  Ring or 0-type pattern and I think that they will likely give different tonal results.  This is not really very scientific, its more of a suck-it-and-see approach.  My intuition is that the differences will not be that pronounced, but they could be. At the very least I do think that the experiment will yield some interesting visuals.

Design

So I have my design brief:

Make a fiddle with a cellular pattern that might interfere with the modal patterns.  Try two contrasting patterns and see what the tonal effects are.  

The brief only considers the tonal aspect of the instruments, but there  will also be a strong visual and emotional component.

I’m ready to start having some fun,  In Part 2 of this series I’ll show at some of the ideas I’ve considered and some other sources of inspiration.


Inside out

In the cellular fiddles  I will be using the ridges between cells to mimic guitar bracing, but unlike on a guitar where the bracing is hidden inside the instrument,  I will make them a feature on the outside.   It will be a sort of inside-out guitar, in the manner of some modern buildings like the Pompidou Center in Paris,

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