another question about chords and scales

[cactus waltz]

Hello,


thanks to this forum I'm getting more and more of a grasp on music theory. There is a very rudimentary thing I'm still trying to grasp though, and that is the number of possibilities for a harmony during any given chord.

Let's say for example that we have a straight I-IV-V progression in in the key of C major. During any chord, I could play a bassline using R-3-5-8, at least. When the band is playing the I chord, I can easily play a riff using any note from the C major scale as that will fit both the key and the chord. But what about the IV and V? Could I for example play their respective pentatonic scale?

[MalcolmAmos]

Yes The chord's pentatonic will work fine. The chord's pentatonic scale will give you three chord tones and two safe passing notes - more than enough for harmonization. And as you pointed out that R-3-5-8 is generic and can be played over the I, IV or V.

As to your other harmonic choices - The C major scale over the entire progression will work. The C major pentatonic over the entire progression will also work. What you try to have is the melody line and the bass line sharing notes. When they do you harmonize both lines. Usually one or two shared notes, per measure, is enough to achieve harmonization. Your question about the IV and V and the C major scale - IV has the FAC notes and V has the GBD notes - 3 of the 7, normally that will be enough like notes to achieve harmonization. Of course your generic R-3-5-8 or the chord's pentatonic scale will be a safe bet.

How much of all this you use depends on the groove you are making. Some time roots are all you need, other times more is needed.

You understand it - go have fun.

[mambo4]

I always think of navigating chord progressions in three layers:
1.) Roots: the absolute most important thing is traveling from the root of one chord to the root of the next chord, in a rhythm that is appropriate for the song.
If I can do that using roots alone, the band/audinece is usually quite happy and everything else is gravy.

for gravy I use:
2.) Chord tones : as you already understand, just 1-3-5-7 of the harmony.

and

3.) Other tones as dictated by my ear.
Some may try to convince you that exploring modes will help, others that exploring chromatics tones will help, but studying these will not reveal any 'tricks' to a good bass line: I feel that if you have a solid grasp of 1&2, your ear will quickly and efficiently lead you to tasteful choices for your"other notes"

As always, the best resource is to listen and learn from the great bass lines of the past.

[MalcolmAmos]

Great advise. Never looked at it that way, but, that hits it on the head.

[cactus waltz]

Originally Posted by mambo4

3.) Other tones as dictated by my ear.
Some may try to convince you that exploring modes will help, others that exploring chromatics tones will help, but studying these will not reveal any 'tricks' to a good bass line: I feel that if you have a solid grasp of 1&2, your ear will quickly and efficiently lead you to tasteful choices for your"other notes"

Yes, I think this is where I'm struggling a bit at the moment. I can quickly figure out notes using R-3-5-7-8 for "bread and butter" and then ponder for a moment to tie the chords together appropriately, with reoccuring notes for example. This goes a long way, actually. But every now and then, like you say, my ears and fingers just sort of lead to something unexpected that sounds interesting and it works, but I'm not sure why.

[MalcolmAmos]

Perhaps it's not necessary that we always know why. Someone told me a long time ago, that a bad note is just one fret away from a good note. The person that figured out the way our fretboard is laid out took care of that for me. That put everything into perspective for me. That is something I don't have to worry about, something I can just take advantaged of.

We study so that when we play we can just play.