Note Positions on the Bass Guitar

 Each of the individual notes that you have just played have a specific note value attached to them (i.e. the "Open" E string has a note value of E). Also, each time you moved your finger up or down a fret, the note value changed as well. Note values are what musicians use to let themselves know where on the neck they need to play in order to produce a certain note. Without getting too deeply into musical theory, we will use a description of the basic musical alphabet to help you learn to identify where every note falls on your bass guitar.

The Musical Alphabet: In Western music, there are 12 different notes that can be played. They are:

A | A# | B | C | C# | D | D# | E | F | F# | G | G#

 Each note is a half-step higher than the one proceeding it and a half-step lower than the one following it. In terms of the bass guitar, a half-step is equal to one fret, meaning that every time you move your finger up one fret - the note value increases by a half step (i.e. If you start on an A and move up one fret, then you have moved a half-step higher to an A#).
As you can see, as you move higher up on the fretboard, the note values increase by a half-step for each fret. This makes it easy to find any note you want to on the fretboard. All you need to do is to figure out which note you are on - and you can then move up or down the neck until you reach the note you're looking for.


Source : mahalo.com