This is a guide on how to tune your bass guitar with harmonics. Tuning with harmonics is a great way to tune your bass because you can hear both notes ringing as you tune the pegs. In reality, you will use 2 methods of tuning. Tuning with an electronic tuner, then harmonics to "fine tune" the bass.
Producing A Harmonic.
Producing a harmonic is rather easy. It will not sound very clear if you don't have your bass plugged in. Put your finger lightly over the 5th fret of the E string. Make sure you are right over the fret. Strike the string with your picking finger. You should use your thumb or a pick when you are tuning. You should hear a high pitched sound. This is a harmonic. It is usually represented in tabs as an * or a +. After making a harmonic, you can release your fretting finger and let the harmonic ring out. If you are not familiar with harmonics, you should practice this:
Example (we're just going to use the * as a harmonic):
Tuning With Harmonics.
Tuning with harmonics will only really work if your bass is already in tune to standard (GDAE, high to low) Harmonics are just a way of "fine tuning." Get you bass into standard with an electric tuner.
Make a harmonic on the 5th fret, E string (as shown above) using your thumb or a pick. Then make a harmonic on the 7th fret, A string. If you did the exercise above, you will notice that the two harmonics sound alike, but if they are not the exact pitch you might hear a beating sound. It sounds like an in and out sound (like a flanger pedal). You will know if you hear it. Make both harmonics (E string, 5th fret and A string, 7th fret) with your thumb or pick and let them both ring. Tune the bass up or down. If the beating sound gets faster you are going more out of tune, as it gets slower and slower, you are getting more into tune. When you don't hear any beating you are perfectly in tune. Do this with the rest of the strings and you will be exactly in tune. This should become a habit every time you pick up the bass.
All the harmonics should sound the same with no beating.