Posted on

Letter: Kenny Hill Responses in AL#98

Letter: Kenny Hill Responses in AL#98

by Alan Carruth

Originally published in American Lutherie #100, 2009



Tim —

I found Kenny Hill’s response (in AL#98) to R.M. Motolla’s study of ports (in AL#96) interesting. I’m not going to answer every point he made; some are more properly addressed by R.M. himself. However, there are a couple of things I would like to comment on.

Kenny wrote: “I’m guessing that Al’s cool Corker was not really constructed as a concert instrument, that it does a good job at its original intended purpose but was not built to prove or disprove the validity of soundports as a useful design element.”

I think the concept of what is or is not a “concert instrument” is slippery enough that we won’t settle it here. Nobody is likely to appear on the stage with something as rough as the “corker” so that in itself excludes it from that class. I will note, though, that several people, including one very fine maker, have remarked that it is at least “not bad”, and R.M. told me that most of the players had a much higher opinion of it when they were blindfolded.

Become A Member to Continue Reading This Article

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.

If you are already a member, login for access or contact us to setup your account.
Posted on

Questions: Book on Acoustics

Questions: Book on Acoustics

by Tim White

Originally published in American Lutherie #73, 2003

 

Lee Parks from cyberspace asks:

I just need to know a good book that teaches fundamentals of acoustics for guitar construction.


Tim White of New Boston, NH
responds:

The GAL has published many articles over the years but the only “book” I know of is the one I put together — Journal of Guitar Acoustics, from seven issues of the Journal of Guitar Acoustics, originally published between 1979 and 1982, which includes the complete collection with addenda, 700+ pages. The Evan Davis thesis bibliography alone makes it worthwhile as an entry portal to the strange world of guitar acoustics. The republished single volume has an updated bibliography and additional material. It can be ordered from me at:

146 Lull Rd., New Boston, NH 03070; 603-487-2696; tpwhiteco@aol.com; www.chrysalisguitars.com/JGA_Page.html. ◆

Posted on

Questions: String Tension and Purity of Tone

Questions: String Tension and Purity of Tone

by Alan Carruth

Originally published in American Lutherie #99, 2009

See also, Questions: String Tension and Pure Tone by R.M. Mottola



Alan Carruth from Newport, New Hampshire writes in response to Pat Bowen’s question in AL#98 about the relationship between string tension and purity of tone:

While there is some truth in the equation higher tension=purer tone, it is, as the editor said, not as simple as that. A lot depends on how you get the higher tension.

When you pluck a string, it vibrates at a set of different, but related, frequencies. For ideal strings, the kind that you only find in physics books, these frequencies form a harmonic series; each one is an exact whole-number multiple of the lowest (or fundamental) pitch that the string makes. Real strings don’t do this, and that affects the way they sound.

Become A Member to Continue Reading This Article

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.

If you are already a member, login for access or contact us to setup your account.
Posted on

Questions: String Tension and Pure Tone

Questions: String Tension and Pure Tone

by R.M. Mottola

Originally published in American Lutherie #98, 2009

See also,
Questions: String Tension and Purity of Tone by Alan Carruth

 

Pat Bowen from the Internet asks:

A generally accepted fact is that the higher the string tension, the more pure the tone. This causes me grief, since I have to build instruments to support the heaviest strings. Even if I don’t recommend them, someone is going to use them. But is this thing about the high tension and pure tone really true or is it just a folk tale?


The Questions Column editor
responds:

The short answer is yes, it is true, and the short explanation is inharmonicity. The higher the tension, the closer the partials are to true harmonic multiples of the fundamental frequency. On p. 115 of his book Engineering the Guitar — Theory and Practice, Richard Mark French states: “...increasing the radius [of the string] or elastic modulus [i.e., stiffness] makes the deviation from the ideal harmonic series worse, while increasing tension or length makes it better.” This is an interesting topic worthy of an article or at least a longer explanation than I’ve given here, which I hope someone will provide.

Posted on

Thoughts on Soundboard Vibration

Thoughts on Soundboard Vibration

by Paul Wyszkowski

Originally published as Guild of American Luthiers Data Sheet #200, 1981



The classic guitar, like the harp but unlike the violin, the mandolin or the zither, has its strings attached directly to the soundboard. In the case of a violin, it is pretty clear that the bridge communicates primarily vibrations which are perpendicular to the surface of the soundboard. But it is not so obvious how the strings of a guitar transmit their vibration to the soundboard. However, a few minutes’ thought and a simple experiment can settle that question.

Back in 1954, J.K. Sutcliffe stated in an article in Guitar News that the fundamental action linking the string to the soundboard is the rocking of the bridge in response to the longitudinal (along the length) vibrations of the string. That is, the front and back edges of the bridge rise and fall as the string becomes tighter and looser (see Fig. 1). Later, Michael Kasha used this idea in his theory of guitar design. As a consequence, this view was accepted by many luthiers as correct.

Become A Member to Continue Reading This Article

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.

If you are already a member, login for access or contact us to setup your account.