Posted on June 13, 2024May 6, 2025 by Dale Phillips Experimental Violin Acoustics Experimental Violin Acoustics by George Bissinger from his 1984 GAL Convention lecture Originally published in American Lutherie #7, 1986 and Big Red Book of American Lutherie Volume One, 2000 It was a pleasure to discuss the “secrets” of violins at the kind of meeting that would scarcely have seemed possible in the time of the legendary Cremonese luthiers. As a member of the Catgut Acoustical Society, which is devoted to all aspects of bowed string instruments from the raw materials (gut?) to the finished product (cat?) and its sound (meow?), I can only welcome this shared discussion. The Society has sponsored the construction of a family of eight violins covering the frequency range of 41Hz to 1318Hz (lowest to highest open string), and has a demonstrated interest in all violin matters whether they are purely practical, subjective, and aesthetic, or purely abstract, objective, and quantitative. The talk I gave at this GAL meeting covered a range of topics concerning violins in which I personally have been involved. These topics leaned rather more to the concrete aspects of violin making such as working with student instruments, testing plates of unassembled (or humidity disassembled) instruments, plate archings, bassbar tuning, and humidity effects, but also included discussion of coupling between enclosed air oscillations and plate vibrations in the assembled instrument. 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 June 6, 2024May 28, 2025 by Dale Phillips Questions: Measuring Guitar Efficiency Questions: Measuring Guitar Efficiency by Alan Carruth Originally published in American Lutherie #73, 2003 and Big Red Book of American Lutherie Volume Seven, 2015 Buck Montoya of Wichita, Kansas asks: I’ve heard and read that acoustic guitars are horribly inefficient (less than 10% if I remember correctly). Is there a method of measuring a guitar’s efficiency that could be performed by the average luthier without the resources of a fully equipped lab? Al Carruth of Newport, New Hampshire responds: I think most instruments are pretty inefficient. Neville Fletcher and Tom Rossing discuss this in their book, The Physics of Musical Instruments. The figure that I’ve been given for the violin is about 2%, and Ervin Somogyi said at the GAL convention in ’92 that guitars run around 5% efficient. It’s not easy to measure the efficiency of a guitar. For one thing there is so little power involved: any source of noise will throw the measurement off. For another thing, guitars are complex sources: even the headstock radiates some sound. You have to take measurements all around at all different frequencies and add them up to find the total. And you can’t take the measurements from close up, since the phase cancellation of the different radiating areas can skew the results. The cheapest calibrated microphone and preamp combination I know of costs several hundred dollars, and it’s probably the wrong kind of mike for this. I wish it were an easy measurement to make: I’d love to know how efficient my instruments are. But try as I might I can’t think of an easy way to do it.
Posted on June 6, 2024May 28, 2025 by Dale Phillips Questions: Measuring Soundboard Vibration Questions: Measuring Soundboard Vibration by Alan Carruth Originally published in American Lutherie #73, 2003 and Big Red Book of American Lutherie Volume Seven, 2015 Gregory Furan of Toronto, Ontario, Canada asks: Over the past several years there have been numerous articles written in many different guitar mags regarding measuring soundboard vibration, that is, tuning tops. Can you give me a reference for where all of the different elements can purchased? Al Carruth of Newport, New Hampshire responds: For tuning plates on guitars or violins, the equipment you need is fairly simple: a signal generator capable of producing a reasonably “clean” sine wave signal over the range from about 20Hz to 1000Hz, an accurate frequency counter, an amplifier that can boost the output of your signal generator to around 12w or more, and a loudspeaker that is matched to the amp and rated for the power. To be on the safe side, I’d get a speaker that was rated for about 1½ times the nominal power of the amp: sine waves have high peak-to-peak voltages. Become A Member to Continue Reading This Article This article is part of the Articles Online featured on our website for Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 3 annual issues of American Lutherie and get discounts on products. For details, visit the membership page. MEMBERS: login for access or contact us to setup your account.
Posted on June 6, 2024May 22, 2025 by Dale Phillips 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 June 6, 2024May 14, 2025 by Dale Phillips Another Method for Calculating the Area of a Plate Another Method for Calculating the Area of a Plate by R.M. Mottola Originally published in American Lutherie #70, 2002 and Big Red Book of American Lutherie Volume Six, 2013 There are a number of reasons to calculate the area of the plate of a stringed instrument. The area of a flat plate can be used to determine the volume of the instrument by simply multiplying the area by the depth. This value is useful in the design of electric guitars and basses to determine the weight of the body of the instrument before it is built. This info can aid in the design of an instrument that balances well when hanging from a strap or sitting on the leg. In the design of acoustic instruments, the volume can be used to calculate the nominal Helmholtz resonance of the soundbox, which may be useful in the tuning of the resonance characteristics of the instrument. The technique specified here will work for any arbitrary shape and is both simple and relatively quick. It is the essential algorithm of a CAD script I use, and is based on a computer graphics rasterization technique. Modified and simplified for use with pencil and paper, it yields a good enough approximation of the area of a plate for the purposes outlined above. 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.
