Jack's 9-string Fanned Fret Harp Guitar Project:
A Five Octave Extended Range Classical Guitar:
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The entire set of pages linked here was transferred from another site, so there may well be a number of broken links or missing images which haven't been fixed. Not everything is updated.
These pages are about the design
and the construction of a nine-string extended range classical guitar
with fanned frets and a five-octave range, built in February and March of 2016. The purpose of these pages is to
share information on the specifications, design process and design details with other guitarists or luthiers who may be interested in
such a design. Such information was very difficult to come by when we started this process.
Although it is admittedly a quirky and experimental instrument, and although there is always
room for more experimentation, this is a very playable design which others may wish to emulate.
Update 06-17-2025
It must be noted that the top bracing failed after about four years and required a serious modification which was not yet on the horizon when these pages were written. Because of the torque imposed by the pull of the large-diameter basses, the treble side of the bridge took a dive down into the body, making the high A4 string hit the frets, while the bass side rose up. I repaired this by putting a steel shoe on the end block and tying the bass strings back to it, to pull the treble side of the bridge back up just far enough to save it. This was a miracle, but it worked.The huge question of accurate intonation on a fanned fret instrument isn't as simple as the math. The calculation of the accurate fret positions is not difficult, but there are several non-linear factors at work that I have no idea at all how to deal with except empirically. The 2013 prototype did not play in tune ever. The 2016 build, #2, plays in tune but only after endless tweaking of the nut and saddle individually for each string. I have been tweaking it for nine years, and I was extremely pleased when a visiting guitarist, who introduced himself as the music director for a certain famous international show (my jaw dropped), complimented me on my guitar's intonation. By very careful tempering, I can play in tune, and yes, I play in better tune than a lot of six-string players who have tin ears.
Even on a six-string - but it's far worse with more strings and fanned frets - the individual strings do NOT respond equally to being fretted. Therefore, as a matter of pure logic, the very best thing would be to be able to adjust every fret individually for every string. As matters stand, on any one string, when tempering the NUT by either shimming it forward or cutting it back, the best that can be done - apparently - is to get ONE diatonic note on the second or third fret to play in tune with the open string. I have done this on every string - and only that ONE note is in tune, and the other notes up to the fifth fret ARE randomly sharp and flat by amounts which show up very significantly with the STROBE TUNER but are NOT VISIBLE WITH THE CLIP-ON TUNER. The same, more or less, applies to tempering the twelfth fret by cutting back the saddle. The saddle must be 3/16" (three-sixteenths of an inch) wide at least. The usual 3/32" saddle will NOT WORK because the notches cannot be cut far enough back - and on a fanned-fret instrument there MUST also be a little notch on the back side of the saddle to hold the string to its correct spacing, otherwise it will slip to the side on the diagonal saddle, as it is tightened.
Above the 12th fret on my guitar nothing is good - it's all sharp. Below the 12th fret there is a good deal of randomness, every fret either sharp or flat, but with an obvious dip around the 8th fret, which is a disadvantage for me in playing with other guitarists, because most uncompensated six-strings play sharp in the middle of the neck (or so I believe.)
In spite of all of this, I do play in tune, because every note is pretty darned close to perfect ET - good enough in general for the clip-on tuner, but not good enough for the Strobe tuner. When I tune, the G string must be just flat enough (a couple or three cents) to bring the second-fret A down a couple of cents so that the open string will be in tune with the G4 on the 3rd fret of the high E string, which runs slightly flat, and so that the fretted A3 will be a hair less sharp to the open A. This tempering is necessary also with the D octave, whereas the A and E octaves run closer to true. As I tune the D string also a hair flat, the D-axis comes into tune, but the open D string is tempered to be between a fourth below open G and a fifth below second-fret A3, because those two notes are still not in tune with each other - on the same string. Then, I temper the D by checking that the 2nd-fret E3 is nearly in tune with the octave harmonic on the low E string, and that the open A string is tempered to lie exactly between the 5th-fret harmonic of the low E and the 7th fret harmonic of the D string. All of this is much too complicated for most guitarists, who don't know how to even think about this, lacking logical minds and not having anyone bring it to their attention, and who would rather settle for just tuning the open strings and hoping for the best - and they play out of tune and don't notice, because their ears are used to it.
The reasons for this are: #1 nylon strings and wound strings respond very differently to fretting because their qualities of "stiffness" and "inharmonicity" are DIFFERENT. Therefore, the wound D and nylon G never play in tune with each other on any guitar. Trust me, or get out your strobe tuner and see for yourself.
#2: Thinner strings go flat on the same fret that thicker strings go sharp on, with the same fret spacing. The treble strings follow one pattern of graduated difference in pitch at each fret, while the wound strings follow another pattern, because they are made of a completely different materials. For this reason, one approach to this tempering would be to start with split nuts and saddles, each being two pieces of bones running at slight angles to each other. This is the final configuration that has resulted from my empirical tempering - but even these are not straight lines, they are curved.
#3: The string is a bridge: it is more flexible and stretchable in the middle than at the ends. The part of the string nearest the nut is the stiffest, and when the string is fretted on the first fret, the height of the nut causes it to stretch the entire vibrating length sharp, and because there is not much string to stretch between the finger and the nut, all of the stretch goes to the vibrating part of the string. When the string is fretted in the middle, some lineal part of this stretch is distributed to the portion of the string which is not sounding, between the finger and the nut, and so it doesn't stretch the vibrating part as much. Not only that: the neck is built with a camber so that, in fact, every fret is a different distance from the string, and therefore every note has a different amount of stretch applied to it. This cannot possibly be calculated, but it can be heard by checking every fret with the strobe tuner.
So: no matter how perfectly the frets are calculated and set, the instrument will NEVER play in tune if the nut, saddle and all the frets are all in straight lines. This is - sorry to say, my friends - absolutely true of every six-string classical guitar, and that's why they play so miserably out of tune even with the best measurements. With conventional straight frets, obviously there is no way in hell: but careful adjustment of the nut and saddle can establish THREE POINTS which are in tune: the open string, the twelfth fret (by adjusting the saddle), and your best diatonic note on the 2nd or 3rd fret of each string (by adjusting the nut.) Between these three points, there will be a good deal of random variation on each fret, and you have to live with it, according to the tolerance of your own ear. As I have now observed, there are very few six-string players who actually care about playing in tune even to this degree, and most do not even temper their saddles much less their nuts. (Isn't that a resonantly pejorative phrase?)
For this reason, having learned my lesson twice, the next fanned fret guitar that I have built will have NO FRETS until I have it strung up and in my hands, and then, I will go over it with a movable fret and a strobe tuner and find out exactly where every fret should be for every string, and then, for the first time, I will have some accurate information about how the math must be adjusted in order to play in tune in the real world.
Continuing with the old text (written about 2020):
This success was only achieved by first building a prototype (2013 - picture at right) which was not such a success, although a very interesting instrument. The proving of a design through successive prototypes is a very expensive process, and since we now know by experience that some of the apparently logical possibilities that appeared reasonable at the beginning of the design process proved to be mistakes, and since we perceive no financial advantage to ourselves in keeping this information secret or proprietary as others have done in the past, we would like to openly share the history of the project, and the conclusions reached, here. We sincerely hope that other guitarists and luthiers will take this design and continue to improve it.
The guitar is a nine string fanned fret design, tuned as follows:F#1 B1 E2 A2 D3 G3 B3 E4 A4.
The first design was drawn in 2013, and the prototype was finished in September of that year. The revised design was commissioned from the same luthier in January 2016, and completed in March 2016.
We used the term "Harp Guitar" for poetic value only, during the fund-raising period when we needed a good sound byte. This design is very different from the conventional 19th-century Italian Harp Guitar design, not only because of its fanned frets, but also because the fanned fret design allows the extra bass strings to be fully functional on the fingerboard, with a full range of chromatic pitches. Most harp guitars both historical and modern have mono-pitched bass strings, which although beautiful sounding are necessarily of extremely limited musical use. This improved design uses the fanned frets to achieve a completely seamless integration of all nine strings into a single workable system, without the use of many redundant mono-pitched basses, as are used in many extended range classical-style guitar designs such as the Yepes- or Marlow-style ten-string or the Swedish "Alto Guitar". It is most similar in design to the eight-string fanned fret "Brahms Guitar" design as played and popularized by Paul Galbraith. However, the incorporation of yet another bass register, down to F#1, demanded stretching the design of the fingerboard well past what has been done with any other fanned fret classical guitar designs to date, and also led to, in the revised 2016 design, the re-configuration of the entire internal bracing design, moving the sound-hole and using a lattice-braced top instead of the older and more traditional fan bracing.
The Design Process:
We used to say that the six-string guitar constituted an "elegant set of limitations." Eventually we began to perceive the six-string guitar as an unnecessary set of limitations and began to consider how it might be possible to improve it. The specific musical reason for this change of attitude was the gradual discovery that in making arrangments for two guitars, the narrow range makes it difficult to place a good bass line underneath a melody and still have room between them for the middle harmony parts without the accompaniment going above the melody, without the redundance of unnecessary unisons, and without the two guitars stepping on each other's parts in various ways. I have not addressed this musical issue in these pages.The Construction Process:
Pictures and a description of the construction process may be found on the details page.The Fund Raiser:
The phase of the project which occupied most of January and February of 2016 was a four-part fund-raising endeavor involving:- Sale of a number of our older guitars.
- Sale of a compilation CD of Jack's original compositions.
- A lecture and concert at the Shelter Theater in San Miguel de Allende
- A request for donations (a number of close friends and fans helped with this project and we are very grateful.)
The 9-string Fanned Fret Harp Guitar
This design is the culmination of many years of thought, and is the logical extension of known design techniques to incorporate two additional, fully functional deep bass strings (tuned B1 and F#1) and one additional higher treble string (tuned A4) to the usual six strings of the guitar. The fanned fret design permits the effective combination of very thin, high-pitched strings - which require a short string length - with very thick, low-pitched strings - which require a long string length - on the same instrument, with all of the strings fully functional on the fret board. (Most competing designs lack complete functionality of the bass strings; that is, the strings added either lack frets, as in the typical 19th-century Italian-style 9-string Harp Guitar, or have unusual fretting arrangements which are either redundant, or which don't allow a complete chromatic bass range, as in the Swedish Alto Guitar.)The Prototype was finished in September 2013 (picture below right). The prototype revealed several design flaws, which was not an unexpected result in such an experimental design as this. After having the prototype built, more than two years of study and reflection were necessary before committing to a revised design. The errors in the prototype design were thoroughly analyzed and the resulting information incorporated in the new design.
Why would anybody want such an unusual instrument? (See also the FAQs.)
The design is a modern update of the Baroque lute, taking advantage of modern string technology and design techniques, and combines in one instrument the ranges of the double bass, the guitar, the Renaissance lute, and the Mexican requinto (that's a small guitar tuned a fourth higher than normal.) It is the most compact, efficient, and playable design yet for such an extended range classical-type guitar. Although the range is not the maximum which has been attempted, this is a very successful instrument in achieving a playable 5 octaves.
The New 9-string Fanned Fret Harp Guitar, finished in late March, 2016, incorporates significant design improvements over the Prototype of 2013 (shown below). The drawing above is Jack's 2015 concept drawing and does not show a number of necessary design details which were filled in by luthier Salvador Castillo.
The 2013 Prototype: (Engelman Spruce and Palo Escrito)
