How to make a Kite Guitar: Difference between revisions

Assuming one is using one of the isomorphic all-3rds tuning, a [[The Kite Guitar|Kite Guitar]] with 6 strings is a little limiting. 7 strings or even 8 is better. A slightly longer scale, say 27", is nice because it makes the frets less cramped. 7-strings and 8-strings often have longer scales anyway.

One way to get an 8-string acoustic is to convert a 12-string guitar. The neck will be sufficiently strong and there will be enough tuners. The new fretboard may need to be wider than the old one, to accommodate 8 courses. The overhang can be filled with bondo to create a nice-feeling neck.

The fret spacing is 1.7 times tighter than a 12-edo guitar. This chart compares it to the standard fret spacing. The spacing between the nut and the first fret is about the same as the space between the 12-edo 9th and 10th frets.Increasing the overall scale length will widen the spacing.

A 6-string Kite guitar tuned in 3rds can be strung with a standard set of strings, but it's not ideal. The high strings will be somewhat slack, and the low strings will be somewhat tight. To find the appropriate gauges, use the D'Addario method: calculate each string's tension from its unit weight, length and pitch (frequency) by the formula T =  (UW  x (2 x L x F)²) / 386.4. For open strings, the length is the guitar's scale. The frequency in hertz of the Nth string of 8 strings tuned in the standard downmajor 3rds with a low string of vD is 440 * (2 ^ (-7/12 + (21 - 13*N) / 41)). For a 6-string guitar, N ranges from 2 to 7. The unit weight is pounds per inch, and is a function of string gauge and string type (plain vs. wound, etc.). D'Addario has [https://www.daddario.com/globalassets/pdfs/accessories/tension_chart_13934.pdf published] their unit weights, thus the individual tensions can be calculated for a given set of strings. One can work backwards from this and select string gauges/types that give uniform tensions using this spreadsheet: http://tallkite.com/misc_files/StringTensionCalculator.ods The desired tension depends on the instrument, and of course personal taste. A steel-string acoustic guitar might have 25-30 lbs. tension for each string. A 12edo 25.5" electric guitar strung with a standard 10-46 set has 15-20 lbs. With a 9-42 set it has 13-16 lbs.   

On a Kite guitar, the scaleLength/1731 formula still holds. But saddle compensation affects the 12th fret note only one and a half times as much as the open string note. Hence for each cent of sharpness, one must flatten by <u>two</u> cents. For example, suppose the 12th fret note is 2¢ sharp of the 3rd harmonic. It's supposed to be 0.48¢ sharp, so the actual sharpness is only 1.5¢. (In practice, if one's tuner isn't this accurate, one might simply round down a bit.) Move the saddle point back by twice this, 3¢ or 0.045". This will flatten the open string by 3¢ and the 12th fret note by 4.5¢, narrowing the interval by 1.5¢ to an exact 41-edo 5th. On the saddle, mark a point 0.045" behind the exit point, and file up to the mark.

'''Method #2:''' The first method serves as a rough check of the saddle points. But it's much safer to check multiple frets. [http://tallkite.com/KiteGuitar/KiteGuitarNotes.pdf This table] has the pitch of every single note on the fretboard. The 2nd page omits some redundant information to make room to pencil in discrepancies in cents. But the open strings aren't reliable, because the nut is not yet compensated (nut compensation must be done after saddle compensation). Use a capo to remove the nut issue. Capo the string at the 1st fret (or 2nd or 3rd, if the capo doesn't fit your 8-string very well). Tune the capo'ed string to the table, then compare the other frets to the table. <u>Important</u>: do not remove the capo during this process, as that will change the tension, and thus the pitch. It's usually sufficient to check every 4th fret, i.e. every dot. Look for the general trend. If the saddle point is too far back, the higher frets will be increasingly flat. Too far forward, and they will trend sharp. If there's an outlier that breaks the pattern, check its neighboring frets. No guitar is perfect. If some frets are sharp and some equally flat, that's the best you can get. Once you find the trend, estimate how much cents error would be expected at the 5th dot, which is almost an octave. That's roughly how many cents to compensate by. (To be super-precise, you could increase the cents by about 3%, so that 6¢ becomes 6.2¢.) Compensate as in method #1 with the scaleLength/1731 formula.

'''Final notes:''' 1) String gauges can affect compensation, so try to choose the correct gauges first. 2) One can avoid nut compensation by using a zero fret. 3) Electric guitars have easily adjustable saddles. Here's an adjustable saddle for acoustic guitars: https://www.portlandguitar.com/collections/bridges They also offer adjustable nuts.