how to choose notes for bass parts

[zorg]

I'm not a bass player, but I have a general question about rock/pop bass parts. I was listening to a song by Phish which has an elaborate, fast-moving bass line, although the chord progression was much slower-moving. I noticed that generally, the bassist would play the root note on the first beat of the chord change, then
proceed to play other chord or non-chord notes in the
remainder of the measure. Broadly speaking, is this a
general formula for pop/rock bass parts? = Start on the root note to establish the chord, and then move to other "decorative" notes?

Another variation I noticed was that sometimes the bass
would skip the tonic at the beginning, so that the chord is
played by the guitars/keyboard, while the bass plays other chord/non-chord notes.

Any other important points for writing bass parts that
would be helpful to know for a non-bass player? Or any
printed/online resources you can recommend? Please share
your expertise.
Thanks,
Jeffrey

[mutedeity]

Bass is like any other instrument tonally. You chose the notes based on the scale, chord progression and rhythmic components of the piece of music. There are numerous ideas about how counterpoint, figured bass and so on work, in fact as many ideas as there are bass players. There is no rule about which notes the bass should play any more than there are rules about which chords a guitar should play.

[Correlli]

Some combination I use:

Major chord - I'll play the 5th interval

Minor chord - I'll play the minor 3rd interval

dom 7th chord - I'll play minor 7th interval

etc

[DocBop]

It is a growing process. Many start with....

Roots
Roots and 5ths
Notes of the chord's basic triad.
Notes of the full chord arpeggio.
Rhythmic variations.
Simple scales like Pentatonic.
Larger scales like major and minor.
Modes of scales.
Start adding color tones.
Start adding chromatic notes.
Implying chords with substitutions.
Pedal tones.
Counter melodies and rhythms.
Symmetric lines.

Its a process of growing your knowledge, learning the sounds, becoming bored and looking for more. The ear has to grow as well. Like symmetric line many new players would shy away from, but as their ear grow their acceptance of more colors and rhythms increases.

So yes there are Rules for creating bass lines, but the rules are to help you get started. As you play and listen and some rules you internalize and forget, but your ear doesn't. In order to break the Rules you first have to know them. As you become bored with your playing inside the Rules you look for new sounds and rhythms. Many stop exploring at some point happy with where they are at, others never stop exploring. If you enjoy what your playing that comes thru and sounds good.

[ogrossman]

Originally Posted by zorg

... play the root note on the first beat of the chord change, then
proceed to play other chord or non-chord notes in the
remainder of the measure...

Sheesh, that pretty much sums up what I do *shrug*