CONSTRUCTION - design, techniques and materials

  • Traditions
  • Timber
  • Tuning the box
  • Bracing patterns for the top
  • Thicknessing and construction
  • 6-fan Asymmetric pattern

    6-fan Asymmetric pattern

TRADITIONS

I build mainly in the style of the spanish tradition - the fan-braced dome fronted design epitomised by the work of Antonio de Torres. Torres was the starting point for me, and I went on to design my own particular take on that bracing method and general making priciples, which has evolved over time. The principle of combined lightness and strength ( as opposed to heaviness and strength!) is very important in traditional building, where all components of the guitar take part in the production of sound and tone. Building traditionally also means using traditional natural materials without employing artificial ones (e.g. carbon fibre, nomex). I have always preferred the sound and feel of a traditional guitar to contemporary styles, and consequently, that is what I make.

I make instruments which are both light and strong, finding an optimum for the sound quality without compromising the longevity of the guitar ( by building too light). The longevity of them I can personally attest to - my eldest daughter still plays my first guitar made in 1993, and in the last few years I have come across two of my earliest guitars, numbers 3 and 5, in perfect working order.

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See photographs of guitars in construction

Apart from building fan-braced guitars in the spanish tradition, I have also developed designs stemming from other european traditions - the X-brace, inspired by the Roudhloff brothers' "melophonic" guitar made in the 1840s, and the Long-bar design, which owes its concept to Laprevotte, the french 19th century maker. Both these designs produce guitars of a different character to the fan-braced one. The sound is more immediate and there is greater sustain. I have found both of them suitable for classical playing as well as crossing over to other styles. But for width of tone-colour range, and expressiveness, you can't beat the fan-braced models.

TIMBER

To make a fine quality guitar you need top quality materials. All my timber is hand selected with great care. It must of course be well seasoned and dry. Timbers are selected for their structural soundness, density, strength, appearance and tonal response. Much thought is given to the matching of timber for the various components of each guitar. This approach has yielded very consistent results.


Soundboard material

Spruce is the classic soundboard material for a classical or flamenco guitar - it is very strong both along and across the grain and produces a very pure, beautiful clear tone.

Cedar is not as strong as spruce especially across the grain, and so requires different treatment i.e. thicknessing and support. The sound from cedar is more immediate, but not pure like spruce, there being many more overtones present. There is much more " going on" with cedar, so there is less clarity, especially in the middle and lower register, but in exchange you get warmer, woodier/earthier basses and mids, and sparkling incisive trebles.

Clearly, spruce and cedar have very different tonal characters, and you may like one or the other, or both. They can both make a lovely guitar. My own personal preference is for alpine spruce. There are other timbers also suitable for soundboard material such as Yellow Cedar and Port Orford Cedar ( North American cypress species), which can make an excellent guitar, although I wouldn't use them for a classical. Sitka spruce is well used in steel-string guitar manufacture, but is not ideal for the lower tension nylon strung instruments - it is just too tough.

Back and sides

For the back and sides I use mainly rosewoods - mostly indian, or when something harder is called for, madagascar, honduras and occasionally other woods such as malaysian ebony, for someone liking a heavier guitar. Indian rosewood is in many ways my first choice, since its medium density and hardness provide an excellent range of qualities - beautiful round tone, strong attack, warmth and clarity. It makes an excellent partner for spruce. Indian rosewood is also very stable compared to the harder rosewoods, which are brittle and can crack if allowed to dry out.

Maple is also a pleasing timber, very different in tone from the rosewoods - it is a much softer material, and so as you might expect, it reflects sound less. Acoustically, this translates into a very smooth attack, and a pronounced mid-range with a lot of warmth in the bass and middle and sweet trebles. Hardness and flexibilty varies greatly between different species of maple and care needs to be taken in selection and treatment of this timber. Birds-eye maple is a good option if you can find a piece that rings well.

Satinwood is an excellent tonewood, reasonably hard and dense, but also flexible, producing powerful, even tone with very good attack. With its lovely pale honey colour and intricate grain figure, it can also be dazzlingly attractive.

Cypress is the traditional material for spanish flamenco guitars. It is extremely light and strong and perfect for the lighter build needed to provide the explosive flamenco attack, airy trebles and earthy basses. It would make a nice classical too, if you like a light airy sound.


Neck

Cedrela or mahogany is used for the neck. These timbers are extremely strong as well as reasonably light - there is a great deal of variation in density, so a piece can be selected according to the needs of the job. The weight (density) of the neck affects the tone and sustain of the instrument. A heavier piece will darken the tone and add more sustain, whereas a lighter piece will give a lighter more airy treble and less sustain. Consequently, very light pieces are good for flamenco guitars and those of medium density are better for classicals.


Fingerboard and bridge

The fingerboard is made of ebony. This adds weight to the neck and the lamination with the cedrela or mahogany lends extra strength.

I use honduras rosewood for the bridge - a very hard and dense material with a wonderful ringing tone.


A variety of natural and dyed woods are used to make the rosettes and purflings, which I always make myself with variations from one guitar to another.

TUNING THE BOX

When luthiers talk about the frequency of the box, we are talking about what is known as the Helmholtz frequency or air resonance - the pitch at which the box strongly resonates, for example, if you sing that note close to the soundhole. This box frequency plays an important roll in the balance of the guitar. When I first started building my guitars had a box frequency of around G ( apart from my very first guitar which was flukily an F), as did most other guitars that I came across. I decided early on to learn to control this body resonance. At G the balance is quite good but the treble is slightly accentuated, whereas the bass does not have much depth, even if it exhibits good attack and sustain. To achieve a more satisfactory balance I have gradually lowered the air resonance of my guitars to produce a more profound bass as well as a beautiful treble. As you move the body resonance below G there is a dramatic improvement in bass response. My guitars are normally tuned between F and F sharp although I have also built guitars with a very low resonance between E and F, both in traditional style ( Hauser-ish) and using an X-braced pattern. These guitars are beautiful and would definitely please any bass nuts out there. But lowering the air resonance also affects the treble, which becomes purer with fewer higher harmonics present.

BRACING PATTERNS for the FRONT

The top is the engine of the guitar, therefore the way it is designed and built has a profound effect on the resulting instrument. I am happy using a variety of strutting patterns, all of which can be made to produce very good results.The dimensions and positioning of the struts and the precise doming of the top and its thicknessing can be varied at will and are fine tuned for each guitar.

As mentioned above, I started out using traditional, symmetrical Torres style fan-bracing, with a well-domed top. But I found that some asymmetry in the bracing improved evenness and a number of asymmetrical fan braced strutting patterns have evolved from this, which I've used successfully over the years. Later I developed the X-brace and Long-bar designs. In 2015 I designed a different way of building the front to employ in my 1940 Hauser I / Bream copy.

Fan-bracing

The strutting pattern for supporting the top which I currently employ ( and have for some years) for classical guitars uses 6 fan struts ( no centre strut), an under-bridge strut on the bass side and an end-bar on the treble side. This was the result of experimenting with a light strut under the bridge in lieu of end bars. Keeping one half of the under-bridge strut on the bass side helps bass control and definition, while I prefer the sound of the treble using the traditional end "V" strut on that side, the two together conveniently contributing to the desired asymmetry of the layout. For my small-bodied guitars I may use 5 or 6 fan struts, while for copies such as the Hauser I, I use the same number as in the original, obviously - 7 in this case.

X-bracing

Model 12 was used for my X-braced prototype which employed an elliptical sound-hole to allow for the closed up X. This design was very successful and it occurred to me that it would work very well in the small- bodied model 08 with simplified strutting, where the long vibrating length of this design can be put to good effect in extending the bass response.

Long-bar bracing

The first of this design was intended for a cross-over instrument, and it made a very nice one, but I was surprised at how good it was for classical playing too. I kept this one and played it for years before selling it on - I loved it.

THICKNESSING and CONSTRUCTION

The thicknessing of top, back and sides is something which varies according to the strength and density of the materials being used, so every component of every guitar is thicknessed according to "feel" ( weight, stiffness, sound) rather than to a set of pre-determined measurements, in order to get the best out of the materials. Spruce is used for the struts on the top, and also for the peones/tentallones ( the small triangular section blocks which glue the top to the sides - cedrela or cypress woods can also be used for these). For the neck, cedrela or mahogany is used, and usually for the back bars and linings also, although these latter can be made of spruce too. I use from 3 to 5 back bars depending on the size and type of guitar being made - my standard model 12 uses 4. The guitar is constructed face down in a low-sided mould. The neck goes right through into the body in one piece, using the traditional spanish method, the ribs (sides) slotting into saw cuts made in the sides of the neck/heel block. Once the back has been fitted the guitar can be removed from the mould. Then the bindings and purflings ( decorative inlays around the edge of the front, sides and back) are added. All bindings, purflings and decorative inlays for rosettes are designed and made by me in the workshop. Everything, in fact, is manufactured in the workshop with the exception of the metal-work - . the tuning gear and fret-wire. The last components to be added are the fingerboard ( ebony) and bridge ( honduras rosewood). Once these are in place and the fretwork completed, the neck can be carved and all the finishing work commences, preparing the wood with graded papers until it is ready for polishing.

Finishing

I finish all my instruments by hand using french polish or danish oil or a combination of both. Using these materials the finish can be a achieved in a thin flexible layer - acoustically this is especially important for the top, so that it's movement is not impeded by a heavy, stiff layer of varnish. French polish is a totally organic material derived from the secretions of the larvae of the lac beetle "Coccus lacca" in India and other parts of south-east Asia. The material is gathered and processed in various ways, ending up with thin sheets that are crushed into small pieces. This is the state that most french polishers acquire it in. Before it can be used it must first be dissolved in alcohol. The polish is applied using a rubber ( a wad of absorbent cotton covered with a cloth) lubricated with a little vegetable or mineral oil. As it dries the alcohol evaporates and the shellac returns to it's hard state. As each layer hardens, another one can be applied until the desired result is achieved. This finish is much more beautiful than synthetic ones because its refractive index is close to that of the wood, so you have an impression of depth looking into it. It is relatively soft and flexible and therefore is not prone to chip, crack or craze like some synthetic finishes and can also be easily repaired by a skillful polisher.

Set-up

Once the finishing is complete the guitar is set-up and left for a few days to settle, after which I begin a process of evaluation and fine tuning - apart from the normal set-up adjustments of nut and saddle, most often this involves tuning the back-bars to even out the response, if necessary, or to lower the air resonant frequency of the box. Sometimes I may shave a bit off the top's transverse bars or fan struts. After each change the guitar is left for a bit and then played a little until I am satisfied with the result. This is part of the job where you really need all your experience and patience, but it is well worth the trouble. Once this is done the guitar is left strung for about a month to settle down and be given some playing in. Then the set up is checked again and adjusted if necessary before contacting the customer.