The term "jazz guitar" used alone becomes ambiguous, as jazz identifies a musical language and consequently has been played with any kind of guitar you may have in mind. Even jazz players do not agree on what jazz is - let's stop here, this will not take us anywhere.
When I am talking about archtop jazz guitars, every jazz musician knows what I mean. Essentially, an archtop jazz guitar is a steel string acoustic guitar, normally electrified, and with a big soundbox reminiscent of cellos. These instruments have received many other names: jazzboxes, cello guitars and plectrum guitars come to mind and should be the same thing.
Jazz guitars are relatively modern instruments. In what follows I will try to give a vision of the evolution of these instruments, followed by a description of the construction details of a modern instrument. The images and descriptions of this last part correspond to a Jaén Rialto guitar.
The birth of the jazz guitar is associated with the names of Orville Gibson and Lloyd Loar.
Orville Gibson already built archtop guitars by the end of 19th Century. His idea was that unstressed wood had superior vibration characteristics. Gibson not only carved the tops of his guitars: the sides were made from a solid block of wood, so he didn't need to bend them (those were the days...). He was the first one making archtop guitars with bridges and tailpieces similar to those in cellos. These characteristics made it necessary for the neck to form a certain angle with the soundbox, as in cellos and modern jazz guitars. However, his guitars had an oval hole instead of the "f" holes of later instruments.
The arrival of Lloyd Loar to the company in 1919 meant a radical change. Loar, a poliphacetic man, was a half-time half-known musician who also found time to serve as a consultant for General Motors and other companies. His hiring for Gibson started an internal revolution as he came to lead almost all the areas in the company. He was not a luthier, but stimulated others to make new developments that, in the case of archtop guitars, led to the famous L5 in 1923 (photo). This guitar was the first with an arched top, floating bridge and tailpiece and f holes, so it can be considered the first archtop jazz guitar. Many pioneer jazz guitarists used it, Eddie Lang among them. Until 1930, this instrument didn't represent an important business for Gibson, but then its radically different design established itself as the standard to follow when talking about guitars for jazz. The L5 could be played at an unusually high volume, and that permitted its use in orchestras with loud instruments as drums and trumpets. By mid 1930s many other makers had similar instruments in their catalogs. This was the case of Epiphone, Stromberg, Martin (with a very limited production) or D'Angelico. The answer from Gibson came with other similar instruments, among which was the Super 400 in 1935, a huge guitar, although not as big as some Strombergs of those years that came to measure 19" in their lower bout.
For some years, the aim was to get the loudest instrument by means of bigger soundboxes and heavier strings. This made possible for most orchestras of the time to have a guitarist in their staff. However, this was hardly a desirable situation for them, as their role in orchestras was purely rhythmical and many wanted (and could) solo as was the style of wind instruments. This situation changed in 1936; Gibson again, with Loar, established a new standard. The ES150 was the first electric guitar that the company made on a commercial basis. Other makes such as Dobro and Rickenbacker had already commercialized electric guitars before, but without much success. Gibson established itself with the guitarist Charlie Christian who used the ES150 with great success (below, Charlie with his ES150). In an article in Downbeat Magazine, Dec. 1939, Christian addressed the guitarists of his time, most of them still resigned to be a mere rhythmical support:
"So take heart, all you starving guitarists. I know, and so does the rest of our small circle, that you play damn fine music, but now you've got a chance to bring the fact to the notice of, not short-sighted leaders, but to the attention of the world. And I don't think it will be long before you're feeding your stomach again as well as your heart. Practice solo stuff, single-string and otherwise, and save up a few dimes to amplify your instrument. You continue to play the way it should be played and you'll make the rest of the world like it."
In the decades of 1940 and 1950, jazz guitars lived their happiest time. Many companies and small artisans had their own line. Among the latter, the name of D'Angelico is mythical, even more now than then. He built 1164 instruments, some among the best guitars of this kind ever. D'Angelico established his small company in 1932, producing guitars mainly of two models: New Yorker (photo) and Excel. The main difference between his guitars and Gibson's were the X braces under the top, that generally make the guitar tone sweeter, although with less volume than its Gibson parallel bracing counterpart.
In this feverish moment, it was Gibson again that established a new concept in 1949: the ES175. This was the first jazz guitar designed more as an electric than acoustic guitar. In fact, its unplugged sound was very poor. Its top was not spruce, but laminated maple (an euphemism for plywood), so it was less sensitive to feedback, a problem that became important as amplifier power grew. The development of this guitar was not a radical departure from the existing models; in fact, Gibson already had laminated electrified guitars (the ES350) two years earlier, but the size of the soundbox in the ES175 was smaller, as was its acoustic response.
By the mid 1950s, something happened that would have a strong impact in the jazz guitar market. Those years saw the birth of the first solid guitars, the Fender Broadcaster (later Telecaster) and the Gibson Les Paul. Sales of jazz guitars with good acoustic characteristics rapidly declined. New musical tendencies in the 1960s almost finished the jazz guitar business, at least for the bigger companies. The 1970s were even worse: the high volume of popular music in those years made archtop jazz guitars anything but practical, with their tendency to feedback, huge size and old look. At a small scale, guitar makers such as D'Aquisto (apprentice to D'Angelico) continued making these instruments, although they also made the more profitable solid guitars. Gibson didn't drop its line of archtop jazz guitars, although sales of these were small when comparing it with the solid guitar market. Other makers almost abandoned it. Jazz guitars were not seen in the hands of rock musicians, as was usual in the 1950s, and were used only in the small world of jazz musicians, farther and farther from the great public.
The 1990s have seen a rebirth of jazz guitars. Many new makers appeared with high quality products that helped redefine the instrument. Others managed to survive through the bad times. This is the case of makers such as Monteleone or Benedetto (photo, Benedetto Manhattan). Other companies like Guild never abandoned these instruments, and in fact they were a substantial part of its catalog. It is difficult to point to a single reason for this renaissance. First, many jazz musicians consider that the sound of these guitars is really unique, and there is a growing number of musicians taking the jazz road after being disenchanted with other types of music. Second, many professional musicians consider that a well cared instrument can last a lifetime (Barney Kessel used his Gibson ES350 almost exclusively for forty five years; he refinished and refretted it several times and is still in good condition today, after many thousands of hours of fantastic playing). If they are going to use it as a working tool, it is of course cheaper than, let's say, a taxi to the taxi driver or a tailor to the executive. There is also a tendency to collect, mainly among wealthier guitar enthusiasts. These guitars can command high prices, and there also exists the possibility of using them as an investment. Regarding the technical problems, mainly the tendency to feedback, there exist today dynamic digital filters that eliminate feedback without much timbre distortion.
The jazz guitar today is a mature instrument. The latest tendencies are for a more or less standardized size of 17", a depth in the sides of about 3", a light construction given its dimensions, absence of elaborate inlays in the fingerboard, small fingerrests that do not mute the f-hole, light tailpieces and bridges, and natural finishes so that no defects in the wood are hidden. Electrification of these instruments is accomplished through the use of floating pickups for which it is not necessary to cut the top; the only knob is a volume control that is usually placed in the fingerrrest. The output jack is usually placed in the soundbox endpin. The following section explains the construction process.
Wood for the tops of these guitars has been traditionally spruce, of which there are mainly three species: European (Picea abies), Engelmann and Sitka. The three have been used with great success, of which, the more expensive instruments feature European Spruce.
Wood for the tops must always be quarter sawn (see drawing), so that the growth rings are very close to each other in the finished top. A different cut would result in a weak top plate, probably not able to withstand the pressure of the bridge on it, thus prone to collapse. Quarter sawing is an obscure way of indicating that the sawing is performed through the center axis of the tree, resulting wedges, two of which are used for every top by gluing them along their thicker sides.
Spruce is lightweight yet highly durable, which is the main reason it had been widely used for aircraft construction before the availability of light composites, and is still in use today in many cases. A sturdy light-weight top in a stringed instrument produces good tonal qualities.
A good top must have compact wood growth rings: the closer the rings are, the more resistant the top is, although the wood must not have unacceptable imperfections like resin pockets or knots. The grain must be as straight as possible, and the cut must be performed in such a manner that the wood fibers run parallel to the sides of the piece. The absence of this last characteristic is known as "run-out", and usually indicates that either the blank was obtained by sawing instead of hammer wedging, or that the tree had some torsional growth defect.
The speed of sound through the grain is very different from that along the grain. These are related to the elasticity of the material, which is measured through a physical magnitude known as Young's module, that is inversely proportional to elasticity. If we compare both Young's modules, we will see that in spruce, and generally all conifers, the difference between them is very high. For example, the ratio of longitudinal to transversal Young's modules in European maple is about 10 (depending on the particular piece of wood, both values may differ a lot, but their relationship shows less variation); other species of non-conifers used in musical instruments show similar values. This ratio for conifers is approximately 15, which is 50% higher than maple. These figures indicate that the elasticity of the wood longitudinally to the grain is much smaller than transversally to the grain, but spruce and other conifers show this property to an even greater extent. The speed of propagation of the vibration is higher when elasticity is lower; thus, the wood will tend to propagate vibrations better along rather than across the grain.
This marked anisotropy in the top wood is very important in the design of the resonance holes in stringed instruments. Bowed string instruments have f holes placed at both sides of the bridge; plucked string instruments usually have central holes placed behind the bridge. Why aren't cellos or violins fitted with a central hole as conventional guitars have? The explanation is that the musician using one of these doesn't want resonances after having stopped moving the bow on the string; only a little echo should remain. A bowed instrument with strong resonance after stopping the bow is inadmissible for a good executant: he himself must have the control to sustain the note. On the contrary, it is desirable that plucked string instruments have a high sustain, as there is not a way for the musician to maintain long notes except through the resonance of the instrument.
In what sense do the longitudinal and transversal Young's modules and the type of resonance holes affect this sustain? The vibrations that the bridge creates in the top travel much more efficiently along the top plate than across it, due to the difference in elasticities mentioned above. F holes intercept the vibrations across the top, forcing the transmission along it. Thus, vibrations coming from the bridge are quickly distributed over the top, losing their energy quickly. The bass bar contributes even more to this effect, as it is placed along the top. As we can see, everything in the violin top plate, from the material (strong, light and very anisotropic) to the resonance holes and the bass bar, is oriented to dissipate the energy in the strings to avoid sustain.
Conventional guitars have a central hole, and consequently the vibrations along the top stop there. A great part of the vibration energy is transformed in vibrations across the top, much slower to develop, so that sustain is higher.
Jazz guitars were designed to be heard in loud environments, with trumpets and saxes, when electric guitars didn't exist or were not affordable. It was desirable that the energy in the strings dissipated fast, in order to get the loudest volume. F hole archtop guitars usually have a very poor sustain in exchange for increased volume. In the 1930s, Gibson mentioned the "cutting power" of its L5; this expresses very precisely the consequences of the new design.
Nowadays, jazz guitars without obstructions along the top (with floating or no pickups) have an important place in the hands of many jazz musicians who want a clear, clean guitar, where notes don't get mixed when playing very fast. There is also a tendency to use cross (X) instead of parallel bracing, which has the effect of making the guitar not so loud while increasing the sustain; making its tone more similar to that of a steel string conventional acoustic guitar. This is a compromise solution that most players seem to prefer today. A different tendency, perhaps not so strong in nowadays, is towards instruments with embedded pickups, that show greater sustain due to the longitudinal obstruction that the pickup hole and weight represent. These guitars, for their limited acoustic response, are in between solid electric guitars and true archtops.
Jazz guitar backs are usually made of maple. Two species are mainly used: European maple (Acer platanoides) and Bigleaf maple (Acer macrophyllium), from USA and Canada. An important characteristic of the woods used is the quantity of curl, in which curly and uniformly colored woods are priced higher. The lack of straightness or uniformity in the growth rings is not considered a defect, as wood in these trees grows very irregularly. For this and for the curl, it is difficult to define low run out here (see above); that is why this concept is rarely used for these woods. Quarter sawing (see above) is the most usual cut for these pieces in order to better display their curl and provide greater stiffness to the finished backs. It is not always done this way; there are curls like that known as "quilted" that display better when the piece is flat sawn. This type of cut allows backs to be made with a single piece of wood without the diameter of the tree being in the Guinness Book of Records. A flat sawn piece of wood would be completely out of the question in a top, as the growth rings would space in the center, resulting in a weak area precisely where the top must be stiffer.
Experience shows that the back of archtops, in contrast with other types of guitars, has great importance in shaping the instrument's tone. It is the back that seems to determine in great measure to the lower-range frequency response of the instrument. A thick back or one without a well executed recurve (the slight depression around the edge) usually results in a treble instrument with lack of low, fat tones. This defect can be an advantage in amplified instruments, as they tend to be more resistant to feedback. The lack of recurve in laminated instruments is one of the reasons why these produce less feedback than their rich relatives, the carved archtop guitars.
Archtop guitar necks have been traditionally made from hard curly maple. This is a very tough wood, and is preferred for this application due to the high tension that heavy-stringed necks must withstand. However, that toughness does not imply good stability. Hard maple is a wood with a regular stability and is sensitive as many others to humidity changes. In spite of not being considered the wood of choice for these guitars, mahogany is a much more stable wood. Of course it is less stiff than hard maple, but this problem can be fixed with a slightly greater tension in the truss rod nut. Additionally, mahogany is lighter than maple, and this makes it a good choice when the weight of the neck is an important issue for the player. However, the look of a mahogany neck may not appeal to the admirer of curly light-colored woods. Its reddish color and the absence of curl (although, sometimes you can find curly mahogany at high prices) is perhaps not so attractive as the slightly pink color and curly look of many hard maple necks. Some of the guitars that I have made had necks cut from bigleaf maple: a slightly more stable but less resistant wood than hard maple. The color of this wood is rather variable; some pieces have a reddish brown tone, but usually they are clear. Curl is quite common and a stunning one known as "quilt" is present in many pieces.
Necks are usually made by longitudinally laminating wood pieces. A correct choice of the gluing faces can diminish some of the lateral movement due to environmental changes in humidity or temperature. Generally, this is not given the attention it deserves. The laminated construction makes the peghead a delicate area, and that weakness is corrected with the "ears" and the peghead veneer. More on this here.
As in most steel string guitars, archtop guitar necks must have some internal reinforcement or tensioning device. I could say beyond any doubt that all these guitars have some kind of adjustable truss rod today. Some old instruments are fitted with unadjustable bars or even no reinforcement at all, although these, especially the latter, are regarded as excessively thick for modern players. An alternative is to find two-way action truss rods, that permit the correction of backbows. This is desirable when the guitar is equipped with very light strings, although this is hardly the case here (we should ask Jim Hall about this.) If the guitar is going to be used as it should, a simple adjustable truss rod is the most common solution.
The fingerboard is usually made of ebony; other cheaper materials have been left out of quality instruments, but occasionally some modern instruments have rosewood or synthetic resin fingerboards.
Frets are not special in any sense. They are the usual alloy of copper, nickel and zinc; I don't know any archtop guitar maker that has tried something similar to the stainless steel glued frets of the Parker Fly electric guitars, probably due to the technology involved. My guitars usually have frets a little bigger than usual; they permit more redressings, avoiding costly repairs, and facilitate bendings that, although not usual in jazz music, are fundamental to the style of some jazz guitarists. The leveling of the frets is still done by the old traditional methods, but it will be necessary to watch carefully the development and diffusion of the methods by PLEK, that can turn all this upside down in a few years.
Usually made of ebony, although sometimes you can see rosewood, maple or boxwood bridges. It has two parts: the foot and the saddle. The former adapts the bridge to the arched top surface, and has two posts that get into the saddle. These posts are threaded so that a thumbwheel can move up and down over them, rising and lowering the saddle to adjust the action of the instrument. The upper surface of the saddle, over which strings press, is almost but not quite perfectly perpendicular to them, thus establishing the compensation. Stairway bridges are not popular among top makers today; this design invariably has an excessive compensation for the plain strings (first and second). Unfortunately, almost all commercial bridges have this design, so I make my own.
Makers of instruments with good acoustic qualities avoid bridges with adjustable metal saddles, as the mass of the bridge must be limited to obtain a good energy transfer from the strings to the top.
The bridge is not glued to the top as in conventional guitars, but is fixed in its position by the pressure of the strings.
Here you can see a Benedetto S-6 pickup installed in the underside of the fingerrest. The latter is made of ebony, and has an aluminum bracket that permits its installation in the side of the neck by means of two screws. This piece is inlayed under the surface of the fingerrest and glued to it with epoxy. The big contact surface between both results in a great resistance to breaking, a problem happening sometimes with more traditional designs. There is a strong tendency today to avoid big fingerrests, as they obstruct a good part of the f hole to the right, having an adverse effect on the sound projection of the instrument.
The Benedetto S-6 pickup is a mini humbucker, especially designed for archtop jazz guitars. It is encased in an "ebonova" housing, a material that makes it very tough. There are other similar pickups that permit their installation without modifying the acoustic properties of the instrument; some of them are attached to the neck with screws instead of being epoxied to the fingerrest as in this case.
The relative position between pickup and fingerrest is very important: if the pickup is very close to the strings, the sound will be distorted. If far from them, the output level will be too low.
The photograph does not show the volume potentiometer, that should be beyond the right limit of the image; some guitars have it placed completely under the fingerrest, as a small wheel similar to the volume control of pocket radios.
Today, more than ever, tailpieces are made of wood, ebony in this case. The rear bracket is made of aluminum covered with a thin wood veneer. This has advantages against the modern tendency of using a Sacconi loop, as it avoids the excessive pressure in the rear rim of the guitar without an excessive extra weight. The output jack goes through the hole opened in this piece. The strings are mounted in six holes, without needing any additional metal pieces.