Bass guitars are tuned an octave lower than a guitar, E,A,D,G. The action can vary considerably due to the broad range of playing styles and the fact that it often takes more physical strength to play this heavier instrument. Scale lengths range from 34" to 30" and the effect of scale length on action and tonality is very noticeable. Shorter scales are easier to play but suffer from poorer tonal response. Longer scales require a greater reach and more work, but they sound better. The longer 34" scale is the most common. Shorter scales often need to be set up with higher action since the strings have less tension and will tend to rattle more on the frets.

The nut, neckrod and saddle adjustments are all interrelated. Changing one adjustment requires changes to the others. The height of strings at the nut is .020" off the 1st fret. With a 34" scale, when measured at the 12th fret, I set the G string at just below 3/32", the D string at 3/32", the A string just above 3/32", and the E string right at 1/8". On a 5 String the low B needs to be up over 1/8". Neckrods are adjusted so there is about .010” of space between the string and the seventh fret when the string is held down at the first and fourteeth fret. This is just a starting point. On a bass, if the neck is too straight the strings may rattle on the frets. Most likely they will also rattle on the first fret when played in the open position. It may be necessary to experiment with the neckrod for a while to get things working.

Setting the intonation adjustment at the bridge is the final step. The pickup design may cause a problem when setting intonation and the pickup height must be determined first. With single coil Fender type pickups the individual pole piece located beneath each string is a separate magnet. If the magnet gets too close to the string, it will pull on the string and knock it out of tune. This effect is more noticeable as you play up the fingerboard. The magnets have varying strengths and they are preset at different heights depending on their design and when they were made. The general rule of thumb is to hold the strings down at the last fret and set the pickup to 1/8” on the treble side and 3/16" on the bass side. If the magnets are down below the coils, the pickups can be closer to the strings.

After all this is taken care of, and with a brand new set of good quality strings, the intonation can be set. Tune the bass with an accurate electronic tuner. Starting with the low E string, check that it is in tune and play a harmonic on the 12th fret. Press the string down at the 12th fret and check to see if it is flat or sharp compared to the harmonic. If it is flat, adjust the bridge piece forward (toward the neck). If it is sharp, adjust the piece back (away from the neck). Repeat this process with the remaining three strings. Be sure and check the height measurements after setting intonation, as they may have changed.

Setting action on basses is far more intuitive than guitars. With guitars you can measure things with fairly predictable results. On basses, it takes a lot of experience with a variety of players to understand what they need. When the owner picks up the instrument, I make sure that they play it in case I need to make adjustments for their style of music. This eliminates returns and complaints and it also creates a better understanding of the techniques that bass players employ.