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From: Ross
Remote Name: 76.101.10.136
Date: 30 Mar 2007
Time: 07:37:59 -0500
Luthier’s Blog 3/30/07 I feel great today. Last week was , for the most part, spent preparing for the annual church youth group camp out in our back yard. Much yard work, clean-up, preparation, elec. wiring, child-proofing, etc. And we were rained out. I had to barbecue the fifty pounds of pork and turkey we’d thawed, anyway, which became the after-church fellowship dinner yesterday. I am very pleased to get back to guitar work. But. I must put myself in Right Mind. Do the Zen thing and organize my bench and workspace. Then I will be able to detail and check out the new thin line electric I am completing for a local customer. Preliminary impressions are good, however, and I am more impressed with the progressively wound Fralin pickups than I expected to be. I’m glad that I can still find enthusiasm for electric instruments. I hope that I can always feel that way. Sometimes it seems that the acoustic purists need to loosen their collars a little bit. I see a lot more informality of mindset among the electric players. There are, however, some stiff ones there too. Stiffness. I believe that I, too, need to be less eager to establish pigeonholes for each new thought that comes my way. Just because one’s seen a lot cannot mean that one has seen it all. Returning to the design work on my robot luthier’s guitar, I learn that he has no legitimate reason for varying the depth of the soundbox from endpin to neck block. He did express dissatisfaction with the relatively small number of non-tapered instruments he has seen from an aesthetic standpoint. Curiously, he found that only two models of this group, both Gibsons, produced what he considered as acceptable tone and volume. It is difficult to draw the conclusion that taper = superior sound, in spite of the proponents who have publicly maintained that non-parallel plates eliminate “standing waves” that are deleterious to tone. This puts the question of what constitutes good tone. I suppose that it may be as well to insert a previous document that I wrote that touches on this point. Coincidentally, it is a view that my robot luthier also holds. TONE SOUP What constitutes good (or bad) tone? Occasionally there has arisen the need to explain my understanding of guitar tone to someone. My first impulse was to use a bunch of physics tech talk which I had carefully memorized in the event someone required me to display my expertise. This, however, did little to better anyone’s understanding of the basic concept. Eventually I began using a cooking analogy which worked a little better. First, let’s begin with a note. For this discussion, we’ll use the A (5th) string of the guitar. The fundamental vibration of this note is 110 cycles per second. In addition, the note is comprised of a series of harmonics occurring at higher frequencies. The most familiar to guitarists is the first harmonic, which can be reproduced by touching the string lightly over the twelfth fret and plucking. It’s frequency is 220 Hz (cycles per second). The tonic (fundamental or even multiples thereof) also occurs at the third and seventh harmonic. A perfect fifth to the tonic occurs at the second, fifth, and eleventh harmonic. The fourth and ninth harmonics are major thirds. The sixth harmonic is a dominant seventh. The eighth is a major second, the tenth is somewhere between a fourth and a diminished fifth. The twelfth is between an augmented fifth and a major sixth. Now, our A string is a lot more than just the fundamental 110 Hz tone. It is also composed of a mélange of even and odd harmonics. No two guitars, with the same gauge strings and the same scale length will play this A string with the same ratio of harmonics to each other. I think it’s time to go to our soup recipe. Let’s call our 5th string open A a potato soup. Our ingredients? The 110 Hz A is potatoes. We’ll call the perfect fifth onions. Major third is celery. Dominant seventh is parsley. Major second is milk. Tenth harmonic? Salt. Twelfth? Pepper. There are other derivations of these twelve which make up other upper partials, and we could assign them random spice names. It is probably obvious to you gourmets out there that we need to assign proportions to these ingredients, and cook them in a certain way to achieve a truly satisfying potato soup. Well, give these same ingredients to ten different cooks (guitars) and you will achieve ten very different tasting soups. An indifferent cook may go heavy on the basic ingredients and overlook the subtle interplay of the spices. An expert cook will use all the ingredients in appropriate relation to each other so that every spoonful will reveal distinct flavors harmonizing in rich complex glory. Let’s see if we can devise a simple intellectual tool to simulate these two soups. Let’s take our imaginary guitar with it’s imaginary A string and replace this string with a shiny new one and tune it up to pitch. Now we’ll imagine striking this string. Boy, new strings sound great, don’t they? Next, we’ll play this string hard for about twenty hours, stretched out over two months. Let’s get our hands good and dirty before we play. Pass it around to some of your friends, maybe after they had just eaten some good barbecue, with plenty of sauce slathered on. Play it outside, too, on a few humid evenings. Retune several times. Listening to our A string now produces a different tone than it did two months ago when it was new. The fundamental tone is still there (mostly), but the upper partials seem to be proportionally less prominent the higher the order. It sounds kind of “thuddy”. It’s potato soup all right, but where’s the magic? With a new set of strings, our guitar’s tone will ideally have a strong fundamental as well as a balanced set of harmonics for each note of each string. Tasty. If you have had the privilege of playing a really fine flattop, maybe a Gibson or Martin from the “Golden Era”, or that of one of the better boutique builders or individual craftsmen, you’ll have noticed that in addition to a fat low end ( in relation to the size of the instrument), the instrument has surprisingly clear high frequency definition. Achieving a big low end tone, or a crisp high end , is not particularly difficult for the builder to achieve. The challenge has always been to have both, along with a powerful midrange, in the same instrument. The success of the builder is reflected in the flavor of the “tone soup”.