In the main lesson on how to tune a bass guitar, I explained how to tune each string to a reference note you know is in-tune such as the bass tuner in the StudyBass tools section. If you’re not sure about what to listen for while tuning, go to that lesson first.
There is another common way to tune your bass. You can tune each string relative to another string on your bass. Think about it if one string on your bass is in-tune, all the notes up and down that string are in-tune. That means you can fret one of the in-tune notes along that string and tune another string in relation to it.
Really, as long as you’re not playing with someone else or along with a recording, you don’t even need to start with a string that is in-tune. You can just decide one string is “in-tune” for your own purposes. Then you can tune relative to it.
The 5th Fret Tuning Method
The most common way to tune is by fretting the 5th fret of the in-tune string and tuning the next highest pitched string (the next skinniest one) to that note. On bass it conveniently works that way for every string.
Starting on the E-string, fret the 5th fret. Be sure to not bend the string or else you will change the pitch! Press straight down and gently. This fretted note is the note A. The next open string needs to be tuned to an A. Play them at the same time and tune the open string until the two notes match in pitch. (If you don’t know what to listen for, go to the first bass tuning lesson.) Now two strings are in tune on your bass.
The process repeats for each string. On the A-string, fret the 5th fret. This is the note D. The next string needs to be tuned to a D. Tune the open D-string to match the fretted D.
Finally, fret the 5th fret of the D-string to get the note G. Tune the open G-string to the fretted note G.
You’re all done tuning your bass. But wait! There is yet another way of tuning tune a bass with harmonics.