The most common work we do on basses is setups. Other common work includes repairing cracks, fret jobs, replacing pickups and fixing saddles. Below is an example of a typical bass setup.
Setup
The following bass setup procedures are the ones that I follow on almost all basses. The specifications are from the Fender website. They work well as a starting point for most bass guitars. These are minimum specifications which are meant to guide you, and should not to be taken as hard and fast rules, as we realize that every player's subjective requirements may differ somewhat based on individual playing style or application (i.e. how hard you pick, finger, slap, pop, or fret the bass).
The first step is to evaluate the neck relative to the bass body. In most cases, it should be parallel to the top of the guitar body. As you can see, this neck is fine. If it were not parallel, then the neck would be adjusted to make it parallel. Some basses have a built in mechanism. On others, the neck is removed and a shim is placed in the neck pocket where it meets the body. Shimming is a procedure used to adjust the pitch of the neck in relation to the body. A shim is placed in the neck pocket, underneath the butt-end of the neck. On a few basses, a Micro-Tilt® adjustment is offered. It replaces the need for a shim by using a hex screw against a plate installed in the butt-end of the neck. The need to adjust the pitch (raising the butt-end of the neck in the pocket, thereby pitching the neck back) of the neck occurs in situations where the string height is high and the action adjustment is as low as the adjustment will allow.
The next step is to evaluate the neck radius. This can be anywhere from 7.25" to virtually flat. We will use this measurement to do the setup. This bass guitar has a neck radius of 10".
Relief
Relief is managed by the truss rod to allow the strings to vibrate without hitting the frets. As the strings pull on the neck, it causes the neck into a bow. Tightening the truss rod straightens the neck and eliminates some of the bow. The amount of bow is known as relief. It is not the same as action. We will adjust the action later.
Tune strings up to pitch. Install a capo at the 1st fret; depress the 4th string at the last fret. With a feeler gauge, check the gap between the bottom of the string and the top of the 8th fret -- see the specification chart below for the proper gap. Caution: Because of the amount of string tension placed on the neck (some basses also feature graphite reinforced necks, adding to the resistance present while the bass is tuned to pitch), it is advisable to loosen the strings prior to making any actual adjustment. After the adjustment is made retune the strings to pitch and recheck the gap with the feeler gauge.
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Neck Radius |
Relief |
This guitar has a neck radius of 10" so the relief is .012.
Action
Action is the height of the strings off the frets. Players with a light touch can get away with lower action; others need higher action to avoid rattles. Action is set at the nut and at the saddles.
Be sure strings are tuned to pitch. The action at the nut is usually set at the factory. In some cases it needs to be adjusted. The action at the nut mostly affects playability down the neck. My method for setting nut action is to hold the string at the third fret and measure the distance of the string off the first fret. It should just clear the first fret. No adjustment needed here.
You can see both the E string and the G string are high. To set the action, be sure strings are tuned to pitch. Using the 6" ruler, I measure the distance between the bottom of strings and top of the 17th fret. I adjust the bridge saddles to the height according to the chart, then re-tune.
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Neck Radius |
String Height |
Treble Side |
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7.25" |
7/64" |
6/64" |
The E and the G strings are set according to the chart above. Each saddle is adjusted to lower or raise the string until the action is correct.
Since the neck radius is 10", the E string is set to 6/64" and the G string is set to 5/64". The outer strings are now at the correct height.
The string radius at the bottom of the strings should match the neck radius. This is best done by using a radius gauge under the strings and adjusting the strings to it.
Pickup height
The pickups are adjusted to get the maximum volume and tone out of the strings without interfering with the string movement. Heavy gauge strings vibrate in a wider arc than lighter gauge strings. The pickup should be close enough without affecting the vibration. The following chart from Fender is a starting point. Depending on the players desired preference, I set the pickups either higher or lower.
Intonation
Without a full description of what intonation is and the theory behind it, the goal of setting intonation is to have the string play in tune all the way up and down the neck. Setting intonation is a compromise in adjustments since the construction of the bass guitar does not allow this to happen perfectly.
A starting point of setting intonation is having the string played open and at the 12th fret producing the same tone.
Final intonation adjustments should be made after all other adjustments have been finished. I set the pickup selector in the middle, volume and tone controls to the max. I make sure the strings are tuned to pitch. Comparing each string open to fretted at the 12th fret; if sharp, lengthen string by adjusting the saddle back; if flat, shorten string by moving the saddle forward. I retune and repeat. Once done, I play the bass and make further adjustments as needed.
After the bass is setup, I recommend the owner play the bass a while. Now that the bass is properly setup, fine adjustments can be made simply and efficiently to meet the ownerâ??s additional requirements.