There are some tips to find the notes and intervals on the neck fast. These tips are also handy when working with guitars with more than six strings.
There is a quick way to learn all the notes on the guitar neck. Therefore we work with the root notes of the low e-string and a-string. These can be divided into three groups:
The groups are based on the dots, the circles in the diagram. These dots will be (almost) always at the same place for each guitar and may occur both at the front and at the side of the neck as dots, rectangles or other decorative element. There are guitars with an additional dot on the first fret; this is not in the diagrams.
The notes of group 1 are situated on the first three dots. These notes are the g, a, b, c, d and e. Apart from the f note f you can now find all the natural notes at a place on the bass guitar neck. The notes of group 2 are situated around the last separate dot. The notes of group 3 really have no recognition point, but these are only two notes.
When you know the natural notes on the e-string and the a-string you can octave up to find the notes on the d-string and the g-sting. For that you slide two squares to the right (in the direction of the body), and two strings upward (in the direction of the g-string).
You can also octave down. For this purpose you slide two squares to the left (in the direction of the head) and two strings down (in the direction of the e-string).
When you octave down the notes on the a-string, it allows you to find the notes on the b-string. This is also a way of finding the notes on the high b-string.
The notes on the high e-string are located at the same position as the notes on the low e-string.
On the twelfth fret a double dot is drawn. The notes in these squares are the same notes as the loose strings. If you look further you see - depending on the amount of frets on your bass - again a number of dots. These dots are on the same spot as the first part of the bass guitar. Thus the neck starts again from the twelfth fret.
This chapter explains that you can lower and raise notes and intervals through respectively the flat symbol (b) and the sharp symbol (#). In addition to the illustrated lowered and raised notes and intervals, there are other, less common lowered and raised intervals.
This way you can raise the note b to the note b#, increase the note e to the note e#, lower the note c to the note cb and lower note f to the note fb. These sound enharmonically the same as respectively the notes c, f, b and e.
You can raise the interval 3 to the interval #3, raise the interval 7 to the interval #7, lower the interval 4 to b4 and lower the interval 1 to the interval b1. These sound enharmonically the same as respectively the intervals 4, 1, 3 and 7.
Additionally, you can also double raise and double lower notes. This is explained in chapter 0.4.
To octave works the same for intervals. Again you can both octave up and down.
It's recommended to also learn the intervals 'under' the 1, because melodies are not only played above the root note (1).
You can visualize the sticking on the high e-string to find the intervals on the b-string. The intervals on the high e-string are the same as the intervals on the low e-string. When you know the intervals 'below' the 1 you can fill in the intervals on the b-string. You actually visualize two stickers.
Another way of visualising the sticking on the upper two strings is to move the sticking one square to the richt, in the direction of the body.
When you play the intervals 1, 2, 3, 4, 5, 6 and 7 in succession you hear the (pure) major scale, the Ionian scale. This scale probably sounds familiar. When you remember how you play this scale, you can find all natural numbers (on at least one place); this way only the lowering and rising remain.
Basically, you can play all scales and other melodic music theory when you know all intervals and notes in one place. However, it's better for the overlooking of the neck if you know the notes and intervals in as many places as possible. Later, this allows you to quickly switch between different scales and thereby play faster and all across the neck.