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Our Great Spherical Friend, Part Three

Our Great Spherical Friend, Part Three

by Frederick C. Lyman, Jr.

Originally published in American Lutherie #9, 1987 and Big Red Book of American Lutherie Volume One, 2000

See also,
Our Great Spherical Friend, Part One by Frederick C. Lyman, Jr.
Our Great Spherical Friend, Part Two by Frederick C. Lyman, Jr.
Improving the Plywood Bass by Frederick C. Lyman, Jr.



Our great spherical friend, the Earth’s atmosphere, is the medium through which sound waves are transmitted from the source to whatever auditor may be present. The relative frequency of the waves, in the audible spectrum, is influenced by the physical characteristics of the sound source, for example, its size. A low-pitched sound may be most efficiently propagated by a relatively large surface area that can exert relatively small forces (per unit of area) onto a wide atmospheric front, which offers the correct amount of resistance to this kind of push. As the sounds go up in pitch, the source becomes smaller, faster-moving, and more forceful per unit of area. But there must always be some area of atmospheric contact.

The physical energy that is put into a stringed musical instrument, whether by finger, plectrum, bow, or whatever, is not at that stage in the form that is needed to agitate the atmosphere in the desired musical way. It has to be converted to this form (or forms) by the intervening action and reaction of the instrument. For example, the stretching and releasing of a string by the act of plucking, does not in itself accomplish much in the way of compressions and rarefactions in the surrounding air. Feeble sounds may be detected by listening very closely to the event; but for us to have musically useful sounds, more vibrating surface area must contact the atmosphere. In our sophisticated violin-type instruments, the energy undergoes a rather complex series of conversions.

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Improving the Plywood Bass

Improving the Plywood Bass

by Frederick C. Lyman, Jr.

Originally published in American Lutherie #10, 1987 and Big Red Book of American Lutherie Volume One, 2000

See also,
Our Great Spherical Friend, Part One by Frederick C. Lyman, Jr.
Our Great Spherical Friend, Part Two by Frederick C. Lyman, Jr.
Our Great Spherical Friend, Part Three by Frederick C. Lyman, Jr.



In our quest for a way to build an inexpensive but musically useful string bass instrument, we have gone on a brief detour. We have decided to explore a bit further an area mentioned in previous articles: the plywood bass. Could there be a way to improve an existing bass of this type, to raise it above the barely acceptable level in tonal response and playability?

Our conclusion, after one experiment, is yes and no. Yes, we think that an average Kay bass (the most common brand) can be altered so as to broaden its range of tonal capability and extend its useful register. No, we can’t work a miracle, it remains basically a hunk of plywood. The job we did on it turned out to be quite a lot of trouble, and like many such experiments it suggests further ways to proceed with the quest. But it seems unlikely that we can ever give this fiddle any real quality.

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This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page.

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Inharmonicity of Guitar Strings

Inharmonicity of Guitar Strings

by Mark French

Originally published in American Lutherie #100, 2009



Strings are uniquely well suited to make music because all their resonant frequencies are very close to being integer multiples of the fundamental frequency.1 The octave is the most consonant interval and the resonant frequencies of a vibrating string are separated from one another by octaves. The expression for the resonant frequencies of an ideal string is familiar to many luthiers.

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The Right CAD Curve

The Right CAD Curve

Bezier Curves, Not Splines, Are Truly Smooth Curves

by David Golber

Originally published in American Lutherie #72, 2002 and Big Red Book of American Lutherie Volume Six, 2013



Bezier curves, as opposed to splines, have been known since the 1970s. They are supported by AutoCAD and AutoCAD LT, but not by many other popular CAD packages. What are they, and why do we care?

It’s easiest to start with an example. Fig. 1 shows the outline of a harpsichord. Look at the curved side. The coordinates of the points are from Kielklaviere,1 which describes the curved side of the instrument by listing the coordinates of points along the side. The curve in Fig. 1 is the ordinary spline through those points. Fig. 2 shows that one of the points is erroneous enough that it clearly makes the curve bumpy.

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A Different Way of Defining Body Shapes

A Different Way of Defining Body Shapes

by Mark French

Originally published in American Lutherie #88, 2006



As I look through American Lutherie, I am struck by the advances in the tools some of us use to make our instruments. While there will always be the traditionalists who do most of their work by hand, more of us are using computer-controlled machines to make jigs or parts. Even the musical instrument lab here at Purdue (www.metalsound.org) has its own CNC router. Large manufacturers like Taylor Guitars use CNC equipment for the majority of their building operations.

An obvious advantage of all this cool stuff is that parts can be made much more precisely. However, the parts can only be as precise as the instructions that are driving the machines. Look through your favorite book on guitar making and find the section on laying out the body shape. Even the best books, like Making an Archtop Guitar by Benedetto and Guitarmaking: Tradition and Technology by Cumpiano and Natelson, offer only the most basic description of the shape. It’s pretty common for the instructions to start with something like “draw a straight line on a sheet of brown wrapping paper to use as a centerline.”

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This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page.

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