Posted on July 1, 2024July 9, 2024 by Dale Phillips Letter: Technical Qualm with Jim Blilie’s Article in AL#100 Letter: Technical qualm with Jim Blilie’s article in AL #100 by Alan Carruth Originally published in American Lutherie #101, 2010 Tim — I really enjoyed AL#100. It’s a nice mix of “technoid,” “art,” and “craft” articles. Lots of good info, but I did see a couple of things I wanted to respond to. First, in Jim Blilie’s article, which was excellent overall, I have a disagreement that rises above the level of minor. He says, on p. 31: “The fact that the relationship between stiffness (Young’s modulus) and density is inherently linear shows that just changing wood species doesn’t affect the stiffness-to-weight ratio very much.” The problem with that is, while the lengthwise Young’s modulus (E) values for both hardwoods and softwoods tend to fall on straight lines, they are different lines, owing to differences in basic structure in the woods. I’ve been measuring the properties of wood samples for several years. I’m enclosing a graph of long grain E vs. density for most of the pieces I’ve measured so far (147 samples), with eyeballed “average” lines drawn in. The softwoods include all of the usual-suspect top woods, as well as white pine and Mediterranean cypress. As you can see, the points fall very close to a straight line toward the left side of the chart. The hardwoods include a lot of lutherie woods (most of the samples are Indian rosewood), and some others, with balsa and blackwood being the end points. As you can see, the scatter of the points is greater, but they do at least suggest a line. One could, of course, draw a single line that took in all of the data points, but at the cost of accepting quite a lot more scatter in the softwood data. Given the relative homogeneity of softwood structure, this seems unwarranted. Besides, the resulting line would not approach the origin at all closely, which would be illogical. As is, the hardwood line is in no way an extension of the softwood line. Balsa, and yew, ’way down on the left, overlap the softwood area, as do a few of the softer hardwoods, such as butternut. Still, compared with the softwoods, hardwoods tend to have higher density for the equivalent E value. 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 March 7, 2024May 21, 2024 by Dale Phillips Side Soundports There’s a Hole in the Bucket by Cyndy Burton A Discussion of Sideports, with Contributions from Kenny Hill, Alan Carruth, Roger Thurman, John Monteleone, Mike Doolin, and Robert Ruck previously published in American Lutherie #91, 2007 See also, “Sideways” by John Monteleone “Herr Helmholtz’ Tube” by Mike Doolin “Three Holes are Better than One” Robert Ruck Just in case we become too self-satisfied with our “discovery” of ports, Alain Bieber, in his article on lyra guitars (AL#88, p. 16), points us to the Neapolitan Gennaro Fabricatore’s ported lyras from the early 1800s. (Alain ported his own contemporary lyra guitar, too.) So we know prominent makers were putting holes in the sides of their instruments in the late 1700s, early 1800s. Many of us are also aware of Carleen Hutchins’ groundwork in the early 1980s. Her “Le Greyère” violin, with sixty-five sideports, has provided a wealth of data about violin resonances since it was made in 1982. She donated the violin to the National Music Museum in 2002. See some great photos of Le Greyère and a list of publications reporting on that research at collections.nmmusd.org/Archives/NewViolinFamily/Hutchinscheeseviolin.html. People are sensitive about putting holes in things. Many guitarists — perhaps more classical guitarists than others — find the ports some sort of denigration, a violation of the sanctity of the guitar’s perfect form. In all fairness, we’ve met with very strong feelings on both sides of the port issue. Luckily, our customer was very open to the idea. He’s not a concertizing musician, but he’s a serious player, and occasionally he plays publicly for special events. We wanted to try ports for him because he has a hearing loss, and we thought ports would be a great way for him to hear himself better. At that time, Robert Ruck had made about a hundred ported guitars, so we figured he had worked out the kinks. He kindly advised us on size, location, and so on. We followed his lead. The result is a wonderful instrument that the owner truly appreciates. We love the feedback — the monitor effect for the player — and when we tested it in a small auditorium with an overflowing audience, we could not discern any loss of projection or quality of sound. But was it louder? Our evidence was very meager and inconclusive. Many makers are adamant that it’s louder with the ports open for both the player and the audience. 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 April 21, 2023March 5, 2024 by Dale Phillips Questions: Guitar Air Cavity Questions: Guitar Air Cavity by Art Davis, Alan Carruth, and Joe D. Franklin Originally published in American Lutherie #63, 2000 and Big Red Book of American Lutherie Volume Six, 2013 Tom Blackshear of San Antonio, Texas asks: Is there a formula for measuring the air cavity of a guitar box, then figuring out how to keep the same amount of air with slightly different box dimensions? Art Davis of San Diego, California responds: Use bird seed. It’s not totally accurate but it’s easy. Pour it in, pour it out, and measure it. Hold the guitar really well because ten or twenty pounds of bird seed is heavy. Also, as per W.D. Allen’s, “Basics of Air Resonances,” in The Big Red Book of American Lutherie Volume 1, changing the air volume doesn’t always do what you think it’s going to. 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 August 1, 2022March 5, 2024 by Dale Phillips 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 August 11, 2021March 5, 2024 by Dale Phillips The Anti-Murphy Concert The Anti-Murphy Concert by Alan Carruth Originally published in American Lutherie #39, 1994 I recently had the privilege of attending a somewhat unusual concert by the Tokyo String Quartet, with some acoustics experiments thrown in. Or maybe it was a physics lecture with live accompaniment? And then there was the quiz show part... I guess I’d better explain. The whole thing seems to have started with the coming together of a number of good ideas. One of the first was a plan by the Acoustical Society of America to produce an educational video on acoustics for grades K–12. This, of course, would require money to do, and the suggestion was made that a benefit concert be held. The members of the Tokyo String Quartet were contacted, and graciously consented. So far, so simple. But remember, we’re dealing with acousticians here. Why not use the opportunity to do a little research? For one thing, while the acoustics of empty halls are reasonably well understood, nobody is really sure what happens when you put in the audience. Since the object of most concert promoters is to have as large an audience as possible, and nobody likes to listen to music in an acoustically lousy hall, it seemed like a good subject for an experiment. And how about that violin thing; you know old vs. new and all? And while we’re at it... 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.
