Copyright © 2019 Mark Roberts Guitars & Ukuleles.  All intellectual property rights reserved.  Phone 503.453.7441​   connect

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DESIGN MATTERS

Form + Function + Features + Force

A misconception about good designers is that our expertise is to create beauty. I believe we should create intelligence - and if we succeed, beauty will appear. 

Most design is all about form and function.

The stringed instrument is also about stored energy or force.  Form, Function, Features, and Force contribute to the other. A change in form will modify both the playability and the tone of an instrument, as it relates to the release of stored energy.

Everything that goes into an instrument from the first pencil stroke of the design of its form, hand selection of a specific piece of wood, thickness of a finish, to the strings will affect instrument tone.

Every choice I make during the creation of a instrument is judged for it's cascading effect upon the instrument.

Sum of Its Parts

Every component that goes into designing, creating, and building an instrument affects the outcome of the finished instrument.

It affects the tone, the playability, and the esthetic appearance of the instrument. 

While the soundboard coupled with the tonebars contributes about 80 per cent of the final tone, it is interrelated to the method and effeciency of the tonebars, and how it reacts sonically with an active back. 

The goal is to make a very effecient air pump, and adjust every component of the instrument to define the overall tone, and how notes react with the player. This is all part of an synergisti system.

While some components contribute to the air pump effect, others stimulate and regulate a desire tone and voice for the instrument. Understanding the system and the components contributes to a finer instrument.

The more I can inform my clients about how an instrument really works, the more they become aware of how every component in the system affects its final  outcome.

If you think what goes on inside and instrument is every bit as important as what it looks like on the outside, we should talk.

We All Have Different Ears

It is pretty easy for all builders to develop their "signature sound". Methodology develops a repeatable outcome.  As long as your ears appreciate that sound, it all good.

We all have different ears with different appreciation for sometimes selective ranges of tone. This may be defined by a style of music one prefers, it may be limited by the effects of aging, or some diminished range of hearing limitations due to exposure.

Consultation with a client will inform me and my client about any preferences of tone and range. This informs my build. Through extensive materials testing and records, I know how to reverse engineer my building process.

What I start with, and how I treat the building processes, will arrive at an instrument with a defined tonal range and fundamental body note. The instrument is truly designed for you, and especially what you prefer to hear.

B14 baritone ukulele. Macassar Ebony and Carpathian Spruce

Whats up with side sound ports?

A face full of sound. A well "tuned" side sound port affords the player a much richer experience performing on their instrument, and the tonal expression of my instruments are balanced for the player and the audience. I have offered this option for nine years.

 

Characteristically, my instruments incorporate a combination of "tuned" soundboard sound holes and optional side sound holes, for an "in your face" sound.

Volumetrically and tonally tuning of sound holes is necessary, whether you have one or twelve sound holes.  It optimizes the combined sizes of the sound holes to the volume of the specific instruments internal air chamber, and the flex characteristics of the body and tonebars, for maximum volume and preferred tone.

On some instruments I incorporate exclusive optimized "tuned" Dual Side Sound Holes", with no sound hole on the sound board.

This requires a uniquely crafted set of tonebars.

Randomly adding a side sound port to an instrument not designed for it will not provide improved tonal response or volume.

It's never appropriate to just cut a hole in the side of an instrument, in hopes of improving the tone, volume, or providing a monitor for the player.

 

Experience, knowledge, and equipment are necessary to efficiently match the soundport/s size/s to the individual instruments internal air volume, vibratory response, and the properly compliant back of the instrument, the addition of of a randomly sized and place side sound port will diminish the instrument.​

 

 

Tonebar System

My tonebar system today is an evolution of the Kasha design, utilizing unique harmonic tonebars, creating a more "string specific" tone response, while still embracing the principles of Kasha. This lends itself to more adaptive and focused designs in building, for different styles of playing; such as fingerpicking of classical, jazz, or strumming styles.

The flexibility of my unique tonebar system allows it to evolve to match the desired tonal output. Evenly balanced, or more selectively focused towards the trebles or bass tones.

I have been evolving the traditional Kasha Tonebar System as long as I have been building.

While I know there are many wonderful methods to achieve a design goal, the product and environmental designer in me tells me that this tonebar system offers flexibility in the tone generating design, that allows me more control and evolution over the desired outcome. 

The sound difference in my instruments speak for themselves. A well rounded and focused tone, clarity, separation, power, and great sustain.

My hybrid tonebar design allows the soundboard and its tonebars to be subdivided into different regions.

Each region is used to define the separate trebles or bass tones of the top. Collectively, they contribute to define the overall fundimental of the top, yet the trebles and bass tones are individually defined for each instrument.

Each set of hand split and selected tonebars is chosen for its desired stiffness, deflection, and pared down during the voicing process of the soundboard, to a defined flexibility to express the tonal vibration of the plucked string energy.     

 

My hybrid tonebar system utilizes a large number of tonebars on the soundboard and back. It is a much more complex systematic tone defining approach than your traditional fan braced or X-braced method.



 

Compound Radius Fretboards

The use of a compound radius fretboard allows for preferred fretboard radii at different positions up the fretboard for better playability, as well as slightly varying string spacing between the strings near the 12th fret, where strings are vibrating and moving the most.

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Cantilevered Fretboards

The optional cantilevered fretboard offers an unrestricted upper bout on my instruments to freely generate more tone and volume, since a fretboard is not glued to the soundboard.​

Match a cantilevered fretboard with a tuned  oval or offset soundhole, or just tuned side sound ports and you have a fully unrestricted soundboard utilizing the entire surface area to generate tone and volume.

This is approaching double the available surface area of a traditionally made instrument.

I have utilized this approach as an option for eight years, paired with "tuned" sound holes and side ports to maximize the efficiency of the body.

N-Tune Intonation

Do your instruments play in tune, at every fret up the fretboard?  Mine do.

Experience, experimentation, tooling, and testing has shown me that every different string set has its own specific string intonation length for each string. That means I need to know that information before building a bridge and saddle, to allow the exact intonation points on a saddle, for each instrument.

This lead me to developing equipment to test each individual string from a select string set being used before a build, to predict accurate saddle slot angles, bridge/saddle placement on the sound board, and string intonation points on the saddle.

Play N-Tune.

Strings

Strings, and the ones playing the strings, are the energy that drive the soundboard, and affect both the air pump and speaker effect of the  instrument. They are often the last thing a builder or player thinks of, or they just put on a popular brand of strings. That is marketing, not engineering and physics. 

The sound you hear from one instrument with a certain set of strings is not the sound you are going to hear from every other instrument with those same strings.

Tone and volume will be defined by the instrument size (air volume), shape, individual sound board characteristics, tonebars deflection, and sound hole/s sizes.

This all relates to the string tension and energy applied to the soundboard, and the additional pressure and release that happens when playing. Each individual top has its own ideal string set tension, to work effectively. Strings are often an after thought, but they need to be part of the consideration at the start of the build, and selectively at the end for the desired tonal quality and volume.

Cello tuned, five nylon string, T14 tenor ukulele

 

Sound Holes

​Sound holes contribute to the overall sound of an instrument.

Initially, the size, shape, and placement of sound holes structurally weaken the architecture of the traditional instrument. Traditionally, this requires "bracing" for the shear purpose of reinforcing the weaken structure that the hole caused. These braces do not contribute to the quality of the tone. They can also limit the amount of active tone generating soundboard by their size and placement. 

If anything, they restrict and diminish it.

By moving the sound hole of the top to an upper corner, reduce its size to an oval, or eliminate it all together frees up the top by eliminating unnecessary "bracing" that stiffens the top or restricts it from vibrating. A "freer" top can also use lighter more responsive tonebars, if chosen properly, to define the tone from the top. It also increases the active tone generating surface area of the top.

I have been building instruments with no soundhole on the sound board for over five years. If you would like to hear more about the benefits, lets talk.

 

 

 

 
The combined hole/s opening size/s also contribute to the tonal definition of the instrument. Too large or too small can constrain or muffle the tone.


The instrument body is an air pump.

The soundboard is a speaker diaphragm.

Plucked string energy activates the soundboard into movement, which in turn starts moving air at a very fast rate of speed in and out of the body through the sound holes, while the surface of the soundboard becomes a speaker diaphragm exciting and projecting air molecules. The effeciency of the air pump will affect the tone and volume of the instrument.


I use a monitoring and testing method during construction that allows me to to optimize and "tune" its volume and preferred tone.

To "tune" the system. This is especially required when any side sound port is added.

Pickups
For the player performing for a larger audience or with a group, or for recording, an onboard pickup is a good  the way to go.

There is an assortment of fine pickups available for installation to match your needs.

I will be happy to discuss your needs and recomend an ideal installation.

If you would like an heirloom instrument with these innovative elements and would like to discuss your dream instrument, contact me,

I will be happy to have a conversation with you.

Sound holes. Mark Roberts guitars and ukuleles