The Craft of Guitar Lutherie – Strength in Numbers


The Next Two Wood Ring Classical Guitars to be Completed Before the End of 2011.

Aaron and I have been working very hard to finish two beautiful classical guitars that he has been building, side by side.  One has a  Western Red Cedar top with Cocobolo sides and back.  It has Bocote trim and a Spanish Cedar neck.  The other guitar has a German Spruce top with Indian Rosewood sides and back. It has Bloodwood trim and a Spanish Cedar neck. We have been working on these two guitars for over two months now.

Although much of this time was spent in crafting the two instruments from their component pieces of wood, a significant amount of time was spent performing extensive tests at every level of construction. Our goal in doing such thorough testing is to have a very thorough scientific understanding of every step in the process of building each classical guitar we produce.

 Although this testing and record keeping takes a lot of time and work, we believe it is well worth it for three reasons.


  1. We want to be absolutely sure that each Wood Ring Guitar is built to last a lifetime. This is done by applying both theoretical and empirical data to our building approach in order to make sure that the most vulnerable parts of the guitar are strong enough to endure decades of playing (strength testing).
  2. We want to be able to reliably reproduce the qualities that contribute to a great sounding guitar (acoustic testing).
  3. We want to continually improve the building process and the finished product from both an acoustic and artistic point of view (record keeping, feedback, and analysis).

Our aim is lofty but we feel strongly about it.  We are committed to creating instruments that will gain in value over time because of their unique artistic beauty, their outstanding sound qualities, and a look and feel that gives each owner that special feeling that only a select few instruments throughout the world can bestow upon them.

Today, I want to discuss the process we use to test the strength of our soundboards. This testing process is very important because:

  1. It allows us to fine tune the soundboard such that we are absolutely sure that each guitar is strong and built to last.
  2. It gives us feedback in fine tuning the top and bracing system such that we can obtain the optimum sound characteristics possible.
  3. It backs up our commitment that the guitar will sound as good or better 10, 20 or 30 years in the future as it does the day it is purchased.

 Sound Board Strength Testing

It is the soundboard that is responsible for most of the sound that eminates from a guitar. When the player plucks or strums the strings, they start vibrating. This vibration is transferred through the bridge and into the soundboard. For standard guitar tuning, frequencies from 82.407 Hz (Open 6th string – E2) to 880 Hz (17th fret on 1st string – A5) are generated. To achieve this, a lot of tension (both static and dynamic) is exerted by the strings onto the bridge and the soundboard. The tension exerted by each string depends on several variables including (a) active string length, (b) frequency of the string, and (c) mass per unit length of the string. For a classical guitar the total tension exerted by all six strings is approximately 85 – 95 lbs. of force.  Due to the way the strings are attached to the bridge, the force of this string tension applies a rotational torque on the bridge and soundboard with the front of the bridge pushing down on the area between the bridge and the soundhole and pulling up on the area between the bridge and the bottom edge of the guitar.

Torque Exerted by Strings on Bridge and Soundboard

As a general rule of thumb, the less mass there is in the soundboard and bracing, the louder and more responsive the instrument will be. Of course there is a limit to this and in reality a luthier must find a balance between the soundboard strength and the amount of mass that the soundboard will have. As mass is removed from the thickness of the soundboard plate and the thickness and height of the braces, the more the soundboard will deflect and warp in response to the tension placed on the bridge by the strings. This is good to a point and every classical and acoustic guitar top deflects a small amount downward between the bridge and soundhole and upward between the bridge and bottom of the guitar. As long as this deflection is kept within some well established design parameter guidelines this results in great sound and a very durable instrument. If this deflection exceeds these guidelines, then over time, the top will start to deform and cracks may appear around the bridge. Ultimately the soundboard may collapse. This effect can be magnified if the guitar is exposed to extreme conditions of varying temperature and humidity.

 Testing Apparatus and Procedure

As part of our testing process, we use a method of soundboard stiffness testing and deflection compliance that was first suggested by David Hurd in his book Left-Brain Lutherie – Using Physics and Engineering Concepts for Building Guitar Family Instruments. This is an outstanding book on the application of science and engineering to the craft of Lutherie. In this book, David proposes that deflection measurements of the soundboard be taken at the point in the building process where the soundboard has just been attached to the sides and the back has not been attached yet. This allows the lutheir to make both soundboard thickness adjustments and bracing height and thickness adjustments based on results of the deflection tests and Chladni pattern tests.  

The apparatus that we use for deflection measurement was hand made and is based on David’s Luthiers Forum series of articles which outline how to build the apparatus and how to use it. The apparatus is simple and is cheap to build.  It is a well thought out apparatus for measuring guitar top deflections. After we built it and calibrated it, we performed extensive testing to establish repeatability and error values and we found that it can reliably measure deflections of a top within +/- 0.001″ which is very acceptable.

There are several stages in the guitar construction process where it makes sense to perform deflection tests involving the soundboard. The first test is done during the selection of the tone wood material as part of the criteria in making sure that we start with an optimal piece of tonewood. The next is done before the braces are added to the soundboard in order to determine an optimal starting thickness for the top. The next is done during the final thicknessing and brace shaving step of soundboard tuning (which is what this blog article is about). The next one is done after the bridge is added to the soundboard. Finally, as the instrument approaches completion, the deflection caused by the tension of the strings is measured above and below the bridge and recorded.

Generally, the procedure we use for measuring and recording deflections is as follows.

Measuring the deflection from a weight placed at various points on a grid placed over the soundboard.

Before we start the deflection tests for the final thicknessing and brace carving stage of construction, we create a very thin paper template with a 1″ x 1″ grid on it which we place over the soundboard so that it is protected from scratches and dents. We use a very thin paper which we tested to confirm that it does not affect the deflection values. Initially we perform a full set of measurements before the bridge is attached to the soundboard.  Once the deflection measurements are taken, we normalize them based on a standard force value of 2 lbs. This is done so that data can be compared with values taken by other luthiers (as proposed by David Hurd).

Next we use a contouring program to map the deflection values for the entire soundboard.

Contour Map of Deflections produced by one of several free contouring applications available on the Internet.


This map is then reproduced on the full size Grid template.

Contour Map - Full Scale for Use in Tuning the Soundboard Braces

This sheet is initially used as a guide for where to take the deflection values and after the data is contoured, it is used as a guideline along with Chladni patterns in tuning the soundboard by adjusting the plate thickness and by adjusting the height and thickness of the braces.  This is an iterative process.  We carefully carve and adjust thicknesses and then take deflection values and perform Chladni tests again. 

Chladni Pattern of 2nd Mode for the German Spruce Soundboard

This pain staking process is repeated until we reach the pre-established guidelines we have worked out regarding the deflection pattern that we want in the final product. It is these guidelines that each luthier must develop and refine as part of their artistic contribution to this process. This allows us to achieve the ultimate balance between strength and the tonal quality we are wanting to achieve for each guitar. There is a lot of work and time involved in doing this but the payoff in a masterfully constructed hand crafted classical guitar is well worth it. I wanted to write this article so that our customers know how much care is taken to be sure the value of these guitars far exceeds the cost and that each Wood Ring guitar is truly an investment that is built to give them a lifetime of enjoyment.

 Links of Interest

Wood Ring Guitars – Unique Hand Crafted Guitars for Exceptional Musicians. Dallas, Fort Worth, Weatherford, Texas.

Left-Brain Lutherie by David Hurd –

David Hurd’s Ukulele Website –

Review of David Hurd’s Book – Left-Brain Lutherie

Quick Grid – Open Source Contouring Program

Of Science, Art, and Society Blog Entry on “Reading Tea Leaves to Predict the Future – Using Chladni Patterns to Create Extraordinary Classical Guitars”


The Artistic Method – Evolution of a Logo

Wood Ring Guitars Logo

I produce most of my art digitally using several graphic programs.  I do most of the artwork for profit as part of my job as a web site designer and developer. I often don’t consider what I do “art” because it is usually a reflection of my customer’s tastes rather than my own. My customers are very particular about color, layout and design and my job is to make them happy so I must leave my own particular tastes aside and go with what they prefer out there in cyber space. 

Once in a while though a project comes along when I am given my free rein and my advice is taken more seriously. Those projects I live for and get the most satisfaction from the resulting art. Such was a recent request from my son for a logo for his web site. 

Coming up with a company name, and identity is often a multi-staged process, this being the case with Wood Ring Guitars. My son is a luthier, a builder of classical guitars. The company, Wood Ring Guitars has evolved over a period of time, first as a germ of an idea and now a full fledged, full service guitar building enterprise. Creating a look, feel and presence to match the quality of the product is the overall goal. That process is an art itself, logo design aside, and is part of an overall marketing strategy. The logo should be a reflection of what the company is all about and say it as simply as possible.  Most customers only look briefly at a logo, so first impressions are important. The logo should make the impression quickly, simply and make it memorable. The web site has been out there for a while, as a resume of good quality guitars, well made and which sound great, but needed a final touch, a memorable logo, to seal the product brand. 

Creating the Logo

It started off as a simple pencil sketch and idea generated by my husband, who loves to take his mental process down on paper from time to time. Those sketches looked like this:

Kitchen Table Thinking Process

Again, not my original idea, but definitely something I could work with! What these sketches did for me was get my creative process working. 

These sketches represent some attempts at combining the WR in clever ways alone and with guitar shapes. The bottom two sketches seemed to have the most appeal. 

The second design on the bottom right (See next image below) had the most appeal due to the darker background and two tone color scheme. It was decided to proceed with that design on the computer.


Sketches Used For Logo Consideration





First a simple guitar shape, similar to a typical classical guitar was created using Bezier curves and straight lines within a graphic program.

Simple Classical Guitar Shape




I like to use a program with the capability of creating vector graphics with layers. It provides me with much more flexibility in the creation process.





Next the guitar was angled approximately 40 degrees.

Guitar Top Outline 40 Degree Rotation

Guitar Top Outline 40 Degree Rotation










Then I added the line representing the neck of the guitar, in this drawing: 

Guitar Top with Line Added

Guitar Top with Line Added





Having the flexibility to use the entire image from this point is the best part of not using a paper sketch. It is so easy to erase, or hide a layer. The line in this example is slightly off center, but it was just enough of the guitar to work to our purpose.




In this next image you will see how I have have removed the portion we want left to imagination giving us more room to add just enough to convey our message, simply.

One Half of the Guitar Shape

One Half of the Guitar Shape










At this point I experimented with the W and R letters. I wanted to make them part of the body of the guitar and still make them recognizable as letters. These letters went through several evolutions. At first I used real fonts and tried my best to resize and rotate them to work in the space. I would place them in the graphic but nothing seemed to work the way I wanted it to. I decided it was best to draw them in using a pen tool and vector lines. I also expanded the canvas size to envision the finished product as a business card as well.


First Design with Text and Letters

First Design with Text and Letters








Next, I added some color and removed the word Guitars, as it seemed redundant and was getting in the way of the simplicity I was after. I also squared up the image in this example, and further bolded the WR letters to make them stand out even more. Here I was looking for design that would also work for an icon or Favicon.


Added Color and Removed Text

Added Color and Removed Text








The final product emerged as a symbol with the hint of the guitar in a bold color matching the web site it will be placed on. The WR is very bold and is what first attracts the eye and it is separated from the fine outline of the guitar, using the bold brown-orange color to highlight that shape. The shape of the guitar and logo “brand” is centered diagonally across the simple square shape. On the web site the logo will sit next to an animated banner to get the final message across. If you would like to see the final logo, placed on the web site click here.

Completed Logo For Wood Ring Guitars

Completed Logo for Wood Ring Guitars


So there is a typical logo creation process, using my artistic method. No two logo creations are the same but evolve in a similar way, from sketch to graphic, with additions and subtractions along the way.





The Blog’s Icon

We put a lot of thought into the symbol we have adopted as our blog icon. It is comprised of three components which are laid out in a two level heirarchy. The first level of the heirarchy is the yin yang symbol. Within the yin yang symbol we have placed two things. In the right hand portion of the symbol we placed an image of the Earth created by NASA’s Jet Propulsion Laboratory. In the left hand portion of the symbol we placed Leonardo da Vinci’s famous drawing called Vitruvian Man.

 Yin Yang Symbol


We chose this symbol because it represents several things that we believe in. We were exposed to this concept during our many years of studying the matial arts. It is a useful way to think when observing the nature of things.

  • The outer circle represents the Universe.
  • The Yin and Yang Fish Tails represent the dynamic nature of opposing forces. Yin is black. Yang is white. Each is represented equally in a way that suggests a dynamic balance and harmony.
  • The Fish Eyes: Yin has an un-shaded circle and Yang has a shaded circle, both are placed the respective center of the Fish Head (large portion) and represent the shades of gray which permeate all things.

In the context of this blog this symbol represents Society which to us means the universe of human thought and behavior from which both science and art have emerged.

 The Image of the Earth

We placed an image of the Earth in half of the yin yang symbol to represent not only the Earth but the rest of the universe as well. The Earth of course is where all art, science, and anything else to do with this blog originate. Seeing Earth in this context hopefully gives us some perspective on things.

 The Vitruvian Man


We placed the image of the Vitruvian Man in the other half of the symbol for several reasons.  First, it was drawn by Leonardo da Vinci who is arguably the ultimate renaissance man, having made many great contributions to both art and science. Secondly, in the sketch, da Vinci explores the proportions of the human body in relation to the elegant mathematical concepts of a circle and a square.  This is a great example of what this blog is all about.


Scientific Method / Artistic Method

This is a joint work done in 1617 by Peter Paul Rubens and Jan Brueghel showing the first telescope ever depicted in a painting.

Very relevant to discussions appearing in this blog are the scientific method, the artistic method, what similarities they may have, and how they are different. I thought it would be good, early on to describe each and compare the two.

 The Scientific Method

There are many websites that give a good description of the scientific method. The Wikipedia entry for the scientific method is very thorough, showing many of the intricate details and complexities of the subject. I have written a concise summary of the important aspects of the scientific method and posted it to this page for future reference for our readers.

 The Artistic Method

In contrast, doing a search on Google for the “Artistic Method” does not yield many useful results. Maybe this is because art is so individually based that there can be no one method that is conducive to good art. Possibly art, unlike science, does not have any sort of universal agreement among its best practitioners with regard to a generally accepted method.

 By changing the search term to Art Methodology there were more hits. The Art Methodology article in Wikipedia states that:

 An art methodology differs from a science methodology, perhaps mainly insofar as the artist is not always after the same goal as the scientist. In art it is not necessarily all about establishing the exact truth so much as making the most effective form (painting, drawing, poem, novel, performance, sculpture, video, etc.) through which ideas, feelings, perceptions can be communicated to a public.

Also it states that different methodologies produce different results which is part of the process in art.

Painters Palette photo by Wendy Harmon (

In this context “Art Methodology” seems to be referring to a specific procedure to produce a specific piece of art for a specific purpose. This is similar in science to developing a specific test procedure to determine if a hypothesis is true or not. What we are looking for in our search for the Artistic Method is an overall approach or framework that could apply to the approach of all good artists in creating art.

 Science and Art

After trying many different search terms and browsing around for several hours, I did find some very good information that will eventually help form a basis for coming up with at least a general framework that describes the Artistic Method. For now I would like to discuss some highlights of what I found regarding Art and Science, how they are similar and how they are different.

Early in my search I found a paper written by Robert Wittig on his website.  Robert, is an artist and art dealer in Chicago. Apparently finding similar results with regard to searching the Internet for information on the Artistic Method, he says that:

“Science and art are methods for examining ‘what is’.  Science uses the ‘scientific method’ which is an extremely well defined method, on which much has been written, and most scientists agree on exactly what is meant, by ‘scientific method’.   Art, at the moment, does not have any widely accepted ‘artistic method’, for examining ‘what is’.”

 He goes on to say:

Science’s method is one well adapted to observing objective reality, using the intellect as the primary tool seeking results that approach ‘truth’, as nearly as possible.

Art’s method is one well adapted to observing subjective reality, using the emotions as the primary tool, seeking results that approach ‘honesty’, as nearly as possible.

I also discovered an very good talk on the TED website by Mae Jemeson who is an astronaut, a medical doctor, an art collector, and a dancer. This talk gives a good description of the important relationship between art and science. Mae is on a crusade to establish a new vision of learning that combines arts and sciences, intuition and logic. In her speech at TED in 2002 she said the following:

Science provides an understanding of a universal experience. It is our attempt to share our understanding and our experience of the universe as experienced by everyone.

Art provides a universal understanding of a personal experience. It is our attempt to share our understanding and our experience of the universe that is peculiar to us as individuals.

Both are our attempt as humans to build an understanding of the universe both internal and external to us. Thus they are manifestations of the same thing. Traditionally, we have thought of art and science as separate things. By accepting this we diminish the potential of the future.

This is a definition of science and art that reveals that the approach is different although the goal is the same – to observe and share our understanding and our experience of the universe.

It is true that science can be done without the influence of art and art can be done without the influence of science. Nevertheless, I believe strongly that each is elevated by the influence of the other. This is historically the case. During the Renaissance, mathematical relationships found in nature such as perspective and beliefs leading to the questioning of ideas that were previously accepted as truth led to one of the most productive periods in the history of both science and art. This new integrated way of thinking led to amazing progress in almost every field of human endeavor over the next 500 years. We should keep this in mind as we deal with the monumental problems we are facing at the beginning of the 21st century.



The Little Man Within the Brain

To create timeless works of art or fine art, the artist must have great command of his senses, that sensitivity to the touch of pressure, cold, heat and pain. Great painters, sculptures and sketch artists have all exhibited great control over their motor functions. They are able to use their hands, fingers, and coordinate their eyes to translate that creativity locked inside their brain to the object of that creativity; art. But how is that possible? Most call it talent, an ability, or a rare and precious gift. Yet, aside from the rare gift to produce such art, the workings of the human brain are the greatest gift of all. That understanding we owe to science.

Cortial Homunculus

Dr. Wilder Graves Penfield (Jan 26, 1891 – Apr 5, 1976) was an American born Canadian neurosurgeon. His work centered on the functioning of the mind, with much study concerning the surgical treatment of epilepsy. Dr. Penfield is also credited with the idea for a Cortial Homunculus, a graphic representation of the way the brain ‘sees’ the body in terms of motor perception of the Primary Motor Cortex (see illustration below). I use the term ‘see’, but this illustration is more a representation of the way neural resources of the brain are delegated to each area of the body. The primary motor cortex is a brain region that works in conjunction with other areas of the brain (pre-motor areas) to plan and execute movements in the body. If you look closely at this illustration you will note how some areas of the body are much larger than others. This indicates that these parts of the body use more of the neural resources of the Primary Motor Cortex than the other areas. 

The idea of the cortial homunculus was created by Dr. Wilder Penfield

If you pay close attention to the way your body moves, your ability to speak, form facial expressions, hearing, and eyesight, it is clear that these areas would require those additional resources. Fine motor skills of the hands and fingers are essential to most artists abilities. Loss of hands, through disease or accident can result in the brain’s amazing ability to re-establish new avenues and to redirect the fine motor resources to the mouth or the feet and toes. If you doubt that high quality art can not be produced in this manner then try this link: The Association of Mouth and Foot Artists Each of these artists has lost the ability to move their hands either through disease or accident. Yet through sheer will, diligence, and through the spirit of creativity these artists do produce high quality art work.


If you would like a clearer visual representation of the motor/sensory homunculus go to this site (from the University of Tampere in Finland). The interactive Java application on the page will allow you to move your cursor over selected areas of the body illustrated by the homunculus to see how much brain resources are devoted to any particular area of either motor or sensory activity.

My Own Conclusions 

Having mused on this subject for several hours to produce this article, I have some thoughts and questions about brains, talent and primary motor cortexes. What kinds of brains must great artists or scientists have? How must their primary motor cortexes be arranged and delegated? Would constant practice and due diligence press the brain to redirect resources to areas the artist preferred to use? I have to wonder just how Leonard da Vinci’s brain was mapped. After all he wasn’t just an artist, but also a scientist and inventor. If it is possible for someone to become an artist without hands at all, then it must be possible for the rest of us to use our hands for even more than what we perceive possible now. 

Other Related Links

Wikipedia online  article on Cortical homunculus

Wikipedia online article about Dr. Wilder Grave Penfield

Museum of Science Web Site Interactive on Leonardo da Vinci – Scientist, Inventor and Artist

     Copyright © 2011-2012 by Danny and Sandra Ringo.  All rights reserved.  Articles may not be reproduced without permission.