Okay pc - here you go.
When a guitar refuses to play in tune, fret spacing is the first thing that needs to be checked. Assuming fret spacing is correct, the second important variable affecting intonation is the stretching of the string, which occurs when a note is fretted. This stretching increases the total length of the string, which increases the tension on the string, and therefore causes the note to play sharp.
Each string behaves differently with regard to sharpening tendency when fretted. There are three related rules which apply here: 1) sharpening from fretting is inversely proportional to pitch (The Pitch Rule). 2) Pitch is proportional to string tension (The Tension Rule); and 3) String tension is proportional to string mass (The String Mass Rule).
The pitch rule tells us that a guitar will display a global tendency to more sharpness as the open string pitch goes down, and the low E string does in fact go sharp more then the high E string. However, the tension rule and the string mass rule also come into play, and we see this especially when we compare the sharpening behavior of the G and D strings. If we were to apply the pitch rule only to G and D, we would expect more sharpening for D then from G. But D in fact sharpens less then G. This is because of the metal winding on D which adds mass.Even though D is lower in pitch than G, it has a higher tension than G and therefore sharpens less. If you want to test this, you can tune your unwound G-string down to D, the string will now sharpen more when fretted at the nut than when it was tuned to G.
We can rectify the tendency to sharpness from fretting by adjusting the total length of the string from string length, and how much adjustment do we make?
To answer these questions, we need to first examine in more detail what happens when a note is fretted. The first component of stretching occurs when the string travels to the crown of the fret ("travel stretch"). However, when a guitarist frets a note, the finger isn't pressed directly down on the fret itself, instead, the finger is pressed down behind the fret, and more pressure is applied to make sure a firm string-to-fret contact is established in order to avoid buzzing. This causes additional stretching ("fretting stretch") Each of these string stretch components must be addressed at the appropriate end of the string for best intonation results.
The correct place to compensate for travel stretch is at the saddle. By setting the saddle itself back and / or by moving the string break-off point back, thereby adding to string length. The reason for this has to do with the relationship between the amount of stretch and the ratio of compression to active string length. As we fret the string on succeeding higher frets, the total string length when fretted, and the string tension increases because of the slope of the fingerboard with reference to the open string. Why then, doesn't each succeeding note get sharper? Because at the same time, the ratio of the compensation at the saddle to the active string length is increasing proportionally.
The correct place to compensate for fretting stretch is at the nut, by setting the string break-off point forward, which reduces the distance to the fret and thereby takes away sharpness caused by stretching. The reason for this has to do with the relationship between the ratio of fretting stretch and the ratio of the nut compensation to inactive string length. As notes are fretted higher on the fingerboard, the ratio of fretting stretch decreases because of the fingerboard slope. At the same time, however, the ratio of nut compensation to inactive string length is decreasing proportionally.
Compensation at the nut is correct when any note on the fingerboard fretted normally, as when playing the guitar, plays in tune. Adding complementary compensation at the nut, distributes the intonation improvement over the entire fingerboard.
The EARVANA NUT will enable a guitar to sound any note in tune anywhere on the fingerboard; assuming the open strings are properly tuned. The guitar will now function accurately as an equal-tempered instrument. For the guitar to function as a well-tempered instrument, however, requires the player's skills in proper tuning of the instrument.
It is well known that equal temperament is deficient because of anomalies in harmonicity which show up especially when chords are played. By careful tuning, the guitarist can restore harmonicity by tuning in small compromises in equal temperament. In this respect, the guitar is different from say, a piano, where the technician can tune each note individually and thus tune the piano in to a well-tempered instrument independent of the player. The EARVANA tuning system optimizes the guitars harmonicity at any position on the fingerboard, not just at the positions where chords are played to tune guitar.
As well, you said you thought that the middle strings were shortened and not the others. Look at this photo and you will see that ALL the strings are shortened, just by varying amounts because of tension, mass and pitch.
http://www.earvana.com/page 12.html Also if you think about it, the only thing that changes with a change in string gauge is the adjustments that are made to correct for the added tension. Generally speaking, the instrument is the same - i.e. same relief, same string height at the nut and the action would be similiar as well. The intonation just has to be adjusted due to the increase in mass as well as tension.
Lastly, did you see what the people who are using this said ?
"I am writing to tell you that the Earvana nut is quite simply...perfect.In fact because of it's adjustable function, it's definitely the Buzz Feiten
system perfected." God Bless you.
Jesse Blue, Luthier Warrior Instruments
"I sat playing chords for hours just to hear them in tune for the first time. I have many customers who will consider this the Holy Grail; the product sells itself.
Steve Daugherty, Owner-Guitar E.R.
"I totally endorse the Earvana tuning system. There is no more excuse for out of tune, out to lunch guitars anymore. If you are tired of those nasty "b" and "g" strings, get the Earvana nut....it works"
Tim Gibson, Luthier, Guitar Tech
And guess what ? I don´t even work for these guys!! I am just dumbfounded by the difference this thing made on my guitars. Outside of your ´Paul having a way out of whack fingerboard, I would bet that you would have the best ´Paul on your block with this nut.
[Edited by Headroom on 08-22-2000 at 04:40]
>Þ)) So, to continue with the Feiten test I did, I ended up not wanting to chop up all my guitars, or to have just one that was better than the others,so I decided that my own tricks I have learned through trial and error would have to do until THE answer came along.(BTW:the Feiten system does require that the guitar be tuned and intonated differently than standard tuning and intonation dictates.) Now I can tell you what I have been rambling about - THE ANSWER IS HERE !! Go to