A setup is best done on a guitar that is well maintained. Keep a 45% minimum humidity for all your guitars, electric or acoustic. You can create a DIY humidifier with a dampened sponge in a plastic bag poked with holes, or purchase a packaged humidifier like a Dampit or Planet Waves Humidipak.
A “setup” is making adjustments on a guitar to attain the ideal playing experience. Both new and used guitars may require small changes to suit a player’s varied needs. For example, are there areas on the neck of your ax that buzz like angry bees? Below are four essential steps on how to set up a guitar. These are steps typically performed by a store technician or luthier. Removing the mystery behind the process empowers you to assess your own guitar and perhaps make some of your own adjustments.
A Fresh Set of Strings
Strings play an important role in both action and tone, and can be chosen specific to the type of guitar, musical genre, and ability. Popular gauges include: light (.012”-.054”) for acoustics and light (.010”-.046”) for electrics. Heavier are chosen for bolder tones, or lighter for easier playing and bending. A neck will flex (bow) more under the strain of heavier gauges.
The amount that the middle of a neck bows away from the strings is what luthiers call “relief.” A small amount helps to prevent string buzz, most noticeably on frets one through seven. A quick way to judge relief of a properly tuned guitar is to fret a string at the 1st and 14th fret and observe the gap at the 7th fret. No more than the thickness of a credit card is needed. If the relief is too great, the action will be high.
There is a truss rod inside the neck that counteracts the bow caused by the tension of the strings. For many guitars this is adjusted by a nut at the headstock of the neck, sometimes at the body end, and for some acoustics, inside
Use the earlier gap test to judge. On a healthy guitar, changes should happen within a half-turn. If the nut turns very hard, or if turning in either direction one whole rotation makes no detectable change, stop and bring it to a luthier.
The nut is the piece in which the strings rest at the headstock. If the strings are too high here it will create higher action overall. where the neck joins the body. Truss rod nuts may take hex (Allen) wrenches, nut drivers, or plain screwdrivers. A neck with too much relief can be adjusted by tightening the truss rod (turning clockwise) and vice-versa. To adjust, first tune the strings down a couple steps. Turn the truss rod nut only a quarter turn at a time and retune to see what change is made. To test, press the string to the first fret. Observe the gap between the string and the second fret. The gap between the open string and the first fret should be no more than double. The string grooves can be recut, but you should take your guitar to an expert who has the tooling and experience to properly adjust a nut.
The bridge is where the strings rest at the body end. Here a balance of clear sounding notes and low action can be made. The string point of contact is called the “saddle.” To test for ideal saddle height, play strings one at a time above the 12th fret and listen for any buzzing. If the notes are clear, but you feel the string is too high, the saddle may be lowered. Acoustic guitars have one long saddle that can be shimmed if too low. This should be done only by an expert.
Electric guitars, however, are often designed for user adjustable saddles. Options include “height” which adjusts string distance off the fretboard (action), and “intonation” which assures strings play in tune on every fret. When notes begin to buzz, raise the saddle just enough for clarity. In the center photo below, all saddles adjust at once via two posts. Intonation is adjustable by moving the saddles in the direction of the length of the string via a small bolt. Test intonation by using an electronic tuner to see if a properly tuned open string also plays in tune at the 12th fret. A string that plays sharp needs to have the saddle moved away.