How to Find a Bass Guitar Note in a Different Octave Using the Two-Strings/Two-Frets Method
Playing bass guitar in a two-octave range can be challenging. With the exception of the five lowest notes, all the notes on a bass guitar occur in at least two places on the neck. The trick is knowing how to find any note in any octave. Knowing where the alternative notes are located allows you to play two-octave scales and two-octave arpeggios easily and efficiently anywhere on the fingerboard. The octave method, also called the two-strings/two-frets method, is great for finding the same note in a different place.
Start by placing your left-hand index finger on a note on the E string. You can find the same note an octave higher by letting your ring finger cross two strings and land on the D string. The ring finger naturally positions itself on the octave of the original note, two frets above the index finger.
Press your left-hand ring finger down for the octave. Your octave note is two strings and two frets above your original note. This method also works from the A string to the G string, and you can use your middle finger and your pinkie. If you have a note on the G or D string and you want to find its lower octave, just reverse the process.