Modifications are made to the position of the nut or fingerboard length. For example, if you play the 12th fret, the resulting note should be exactly an octave higher than the open string. There are in fact compromises and for a select few ...they may always be disappointed with the intonation of a fretted instrument. Here’s how they work: Turning the screw clockwise (with a simple Phillips or flat-head screwdriver — being careful not to ding the top with the handle as you turn the screw) pulls the saddle back toward the bridge, which corrects a string that frets sharp. Old strings often fret sharp and don’t give you a true reading of your intonation. Intonation is then adjusted according to slightly offset tunings which are determined by string gauge, scale length and action. Only after any issues that can contribute to poor intonation are corrected do I … Site Map | Privacy. Cheaper acoustic guitars are likely to have a 'straight' saddle, to keep production costs lower. So don’t invite us to that 38-string guitar’s intonation adjustment! An acoustic guitar generally has a fixed saddle (of bone or whatever). By Mark Phillips, Jon Chappell, Hal Leonard Corporation . Tune your instrument to pitch and fret each string naturally at the 12th fret. to avoid placing the saddle too close to the bridge pins. This is a more costly, time consuming method which may be required when good intonation can not be achieved using a pre-made saddle. Martin Dreadnought 25.4" Ebony was used to fill the original saddle slot prior to reslotting. If the instrument has any playability issues a set up should be performed along with the saddle upgrade. You can use whatever method you feel pleases your ear. A bridge slotting jig serves as a guide for my laminate trimmer. When correcting poor intonation on an acoustic guitar I use an electronic tuner to evaluate the strings tuning at the 12th fret. When pre-made saddles are not available thru retailers or from the original manufacturer the saddle must be made from scratch. Physically moving an acoustic guitar bridge to correct the intonation would leave behind a nasty unfinished area on the top which would be easily noticeable even with touch up. If notes played at the 12th fret are dramatically sharp or flat, changes to the strings length and position of the saddle (or shape of it's crown) may be necessary. issues that can cause intonation problems. 'Straight' saddles are not the best at providing good intonation on a guitar. It is either too close to the fingerboard causing sharp intonation, or too far, causing flat intonation. issues that can contribute to poor intonation, length is added to the instrument's scale length to compensate. I have always found intonation to be far more frustrating on shorter scale instruments. Check the bridge for damage/cracks that could cause bad intonation; Possibly replace the bridge piece entirely with a 'compensated' saddle. Compensation of the nut can be achieved in different ways. People often bring an acoustic guitar into the shop complaining of poor intonation. Other methods include using harmonics to tune or tuning 2 particular chords until they are in tune with one another. Jon Chappell is a multistyle guitarist, arranger, and former editor-in-chief of Guitar magazine. When possible (and appropriate), the original slot is filled and re-routed to correct the problem. Put on brand-new strings before you adjust the intonation. I record this information for reference while making adjustments. You can tell when your intonation is out if an open string harmonic at the 12th fret (lightly touch string at the 12th fret and pluck it) and the fretted note one octave higher (hold the string down at the 12th fret and pluck it) are not the same. If the 12th-fret note is slightly higher than an octave, your string is fretting sharp; if the 12th-fret note is slightly lower than an octave, the string is fretting flat. Earvana® is one example of a prefabricated compensated nut. Intonation refers to the accuracy of the pitches produced by fretting. The Buzz Feiten Tuning system® is another method. When the correct placement is not possible a new bridge is made It is quite common to see this scenario on Martin guitars built in the 70's (though they are not the only example). You can correct a string’s intonation by moving the saddle away from the nut if the string frets sharp and toward the nut if the string frets flat.