-about the bridge
-about the body/neck join
Q: You've changed your bridge pin placement over the years. Why?
A: I used to place my bridge pins in a straight line (parallel to the front of the bridge) -- a la Martin. But such an arrangement encourages an all-too-familiar crack (one running through the bridge pin holes) and, ironically, the better (i.e., more quartered) your bridge stock, the more this crack is encouraged! So, in 1999, I decided to place the bridge pins in a gentle arc ( or "smile"). In fact, if you look closely, you'll see that I decided to do more than that: The "smile" is actually rotated slightly -- a "crooked smile", really -- so that its two endpoints (the two outside E strings) are approximately equidistant from the saddle. This ensures a more uniform "break angle" as the strings pass over the saddle -- furthur enhancing a balanced sound among all the strings.
THE BODY/NECK JOIN
Q: Why attach the neck with a screw rather than with glue?
A: "Traditionally" (ie. since about the turn of the century), a steel-string's neck was attached to the body with a dovetail joint. As additional insurance (against lateral movement), the joint was secured with glue. When a neck re-set was required, that joint had to be first unglued. The trouble was (and is), the methods for loosening the glue (heat and moisture) are both potentially damaging to the instrument's finish (among other things). To help minimize this danger, many makers are now using more "mechanical" means of attaching the neck (bolts, screws, etc). Such joints, provided they are well-fitted, are no less reliable than the traditional glued dovetail. Their advantage, to repeat, is that they are more easily undone. Since late 1998, most Threet guitars have featured a non-glued dovetail (a traditional glued dovetail is available on request). Although the fingerboard's tongue (ie. where it passes over the body) is held down with glue, the dovetail itself is secured with a screw (visible through the soundhole, in the center of the neckblock). Of course, re-sets are still to be done only by a professional(!), but the hope is that by making this routine maintenance easier for those professionals, Threet guitars will continue to be well set-up and eminently playable well into this new millenium. (I just had to get that word in there).
Q: What effect do different woods have on the sound of a guitar?
A: I'd like to narrow the question. First, it is important to realize that no two pieces of wood are exactly alike. Even taken from the same tree, two pieces may differ greatly in their density, stiffness, grain orientation, etc. Still, by holding certain things constant, generalizations can be made. Keep in mind, though, that these can only be generalizations...To begin, let's list some of our constraints. Let's assume that we're speaking of well-seasoned, quartersawn wood - the sort you typically find on better made guitars.
Q: What do you mean by "well-seasoned"?
A: By that I mean that the wood has been carefully and properly dried so that there will be little shrinkage and/or distortion as the instrument ages.
Q: And "quartersawn"?
A: Well, oddly enough, to understand the term "quartersawn", you should begin by imagining a log - and an axe. Set the log on end... split it lengthwise, down the middle (through the center growth ring)...thus:
Now take each of those halves and split it in half.
Do this again with each of those halves. Repeat. Repeat. Repeat.
The resultant multitude of wedge-shaped pieces that you have thus created are all perfectly "quartered". What's more, if you were to "reassemble" the log, you could pick up any two adjacent wedges, "open them up" as though they were a book, and thereby create a "book-matched" set of wedges - suitable, perhaps, for building a rather nice instrument.
Of course, if this were the way logs were really cut, there'd be a lot of waste. Wood cutters (those who supply to instrument builders) do their best to mill (cut) pieces which are truly quartersawn but many pieces will, of necessity, have to be somewhat "off-quarter". The point is, the more "on-quarter" the piece, the stronger it will be. And the stronger it is, the more you can thin it. And the thinner it is (to a point...), the more resonant it will be.
Q: So, assuming we're speaking of well-quartered, well-seasoned wood, how do different types of wood affect the guitar's sound?
A: This will be brief - and, remember, these are only generalizations.
Though many woods are suitable, here are three popular choices:
Sitka spruce is very stiff for its weight. It has a strong initial attack and, because it can be quite thin, it can be quite resonant.
Engelmann spruce, though also very stiff, is a bit less stiff than sitka. Its attack is less strong and results in a "sweeter" sound.
Cedar is considerably less stiff, and results in a "softer" more "mellow" sound.
BACK & SIDES
While it is generally acknowledged that the top is the soundboard - "produces" the sound, as it were - it is also clear that the back & sides "color" that sound. Here's my take on what the most popular woods do.
Mahogany has a strong initial attack, but not a lot of sustain. This makes it a great choice for fast fingerstyle or for any style where you want the notes to "get out of the way" of one another. It also tends to emphasize the treble end of the guitar's response. Some described its sound as "dry".
Rosewood has an "okay" initial attack (compared to mahogany's) but lots of sustain/resonance. This makes it a great choice for slow finger style or for any players who want lingering notes to help them create a lush sound. It is also more "bassy" than mahogany. Some have described its sound as "chocolatey". (I think they have a rich, dark chocolate in mind here...)
Koa has a stronger attack than rosewood and more sustain than mahogany. It is a great, though often expensive, choice for those wanting an instrument suited to many styles. It tends to emphasize the guitar's mid-range. How to describe its sound? Milk chocolate? Coffee? Latte?
Q: Should I humidify my guitar and, if so, why?
A: Some people, sometimes should humidify their instruments. Indeed, some people, sometimes, should even de-humidify them. Here's the explanation...
The woods that guitars are made of move quite a lot as humidity changes. The wood shrinks as it dries out and swells as it becomes moist. If guitars were like little sweaters (shrinking uniformly), this would not be a big problem. Unfortunately, wood doesn't shrink uniformly (it shrinks more across the grain than along the grain, for instance). Moreover, the woods that comprise most guitar tops and backs have quite different rates of shrinkage. For example, spruce shrinks (and swells) far more than rosewood. The result is that, as humidity changes - and, especially, as something called "relative humidity(RH)" changes, your guitar will become stressed. The top will want to shrink more than the back and sides will want to allow and a cracked top will be the likely result. It is important to realize that relative humidity changes from location to location, from season to season, from day to day, from hour to hour. Most builders, realizing this, keep their shops at a "happy medium" of 45% RH. This helps to ensure that their instruments can be subjected to the widest variety of humidities (from Alberta to Zaire) without being subjected to the greatest amount of stress. This is not to say that being built at 45% RH prevents cracking. It just reduces its likelihood.
Wood is amazingly resilient, actually, and can even acclimatize over time. But it can only do this if its adapting to a gradual change. That is one of the functions of a humidifier or dehumidifier (desiccant). If you live in a climate which is much drier or much wetter than 45% RH, you can use these devices to ease your instrument's transition to your climate. Talk to your local guitar technician about how this can be done (basically, think of it as a "weaning" process).
Once "weaned", a humidifier (or desiccant) may still be required occasionally. If you live in a climate with wild swings in humidity (Alberta, for instance), such devices may be helpful. On extremely dry days (or months...) humidifiers can help a great deal - provided they are used correctly. The crucial thing to remember is that guitars (wood, in general) cannot abide abrupt changes in temperature or humidity. It is these abrupt changes that create the greatest problems. Consequently, if you use a humidifier (or desiccant), you must do so carefully. You must monitor it every day. Above all, you must NOT (in the case of a humidifier), forget it, let it dry out totally and then (usually with much fanfare and alarm) re-fill it, smug in the "knowledge" that you have forestalled disaster. Quite the contrary. In doing this, you have now, in fact, subjected the guitar to the very thing it hates most - an abrupt change in humidity! The proper use of a humidifier requires that you check it every day and keep it (and thus the instrument) at a somewhat constant humidity.
Q: Let's say I've "weaned" my instrument as much as possible, but I live in a place with fairly wide humidity swings. How do I know when to humidify or dehumidify?
A: Wood is a lot like your own skin (Skin can acclimatize too, but it also reacts to abrupt changes in humidity). Certainly, if your skin feels dry, it's time to humidify your guitar - or, at least, to look at it carefully. The same holds for excess moisture.
Q: What do you mean by "look at it carefully"?
A: Guitars are almost always built with a bit of an arch in the back. As a guitar becomes "wet", that arch will increase. As it becomes 'dry", the arch will flatten out. These are the changes to watch for. Of course, in order to notice the change, you will have to become familiar with what your guitar looks like under normal circumstances. Knowing this is a good idea anyway. By knowing it, you might be able to notice a host of other potential problems when they arise - e.g.,. a loose brace.
Q: I'm headed off to places unknown. How should I pack my guitar for travel?
A: The better its case, the better its chances of survival. Calton cases are my personal favourite. For their weight, they are extremely strong, and their padding is excellent. Still, no case is exempt from the hazards of an errant forklift. So no case will totally ensure your guitar against that sort of damage. Still, there are other hazards your instrument will face - ones which, fortunately, you can guard against.
1) Falling - Most cases have a built-in neck rest, which, in the event of a fall, will prevent the neck from moving any great distance. Trouble is, in most cases the headstock is unsupported and is quite free to move. Think about it...the headstock, with its attendant tuning machines, is quite heavy. If it is free to move while the neck is "frozen" a break will surely result. To safeguard the neck/headstock area, the headstock will have to be equally as immobilized as the neck. On request, Calton cases will provide "travel wedges" with their cases. These are simply fabric-coated foam wedges, one of which is placed below the headstock, the other placed atop it. When the case lid closes the foam compresses to support the headstock. You could try making some wedges yourself...alternately, roll up some socks and use them instead. Remember, what's important is to immobilize the headstock. That means equal pressure both above and below it.
2) Dryness - Remember that abrupt changes in temperature and humidity are your guitar's worst enemies. Cargo holds of airplanes, especially, can hold a variety of dangers. Is the hold heated? Most are, thanks to the presence of many a pet. Are they humidified? You must be kidding! On cold days - or long flights- you must assume that the hold is far drier than your home and you must take appropriate action. If nothing else, place half of a (newly halved) potato in the pickbox. It will gradually release humidity - hopefully enough to see the instrument to its new destination.
3) It's new destination - If this new destination's average humidity is quite different from your departure point, steps might have to be taken to either "insure against" or "wean toward" the new humidity.
|©Threet guitars 2002 - 2006|