The theory behind 3rd and 5ths?

[Chad T]

I sometimes substitute a 3rd or a 5th for the root note, but I pretty much do this by ear. There are cases where it clearly works and times when it doesn't.

Can somebody explain the theory behind what makes a substitution 3rd or 5th work or not work?

Hope that question makes sense. Thanks!

 

[MalcolmAmos]

Off the top of my head, I often pedal the 5th or the root when the solo is being played. Why? It keeps me in key and does not get in the soloest's way.

Using the 3rd instead of the one calls attention to the major or in b3's case the minor key.

I have a friend that will play R-3 instead of R-5. Asked why, he just srugs.

 

[BassChuck]

Root, 3rd, 5th whatever you play under a chord has a different feel to it. The root will have a more solid and grounded feel, and so you may find it most useful to start and end phrases with root position chords. 3rd's have a more 'active' feel and generally work nicely in the middle of the phrase. Sometimes how the note connects with what comes before or after is more important than the relation of the note to the chord (in other words thinking horizontally instead of vertically).

Chord progressions, and the forward energy of the music is very important, and how that energy relates to the style is also an important element of note choice.

All that said, if you have a chance to learn a bassline as recorded, do it. Then change things around and see how you feel about it. You might find something new and exciting, or you may understand why a note was picked. Either way, keep experimenting with new and old material. Eventually you'll have your own opinions and style.

 

[mambo4]

Can somebody explain the theory behind what makes a substitution 3rd or 5th work or not work?

It is probably too basic to mention for the OP,
but 3rds and 5ths come in various flavors
3rds can be major or minor
5ths can be perfect , augmented or diminished.
which 3rd or 5th you favor depends on chord quality
so it's possible to play the wrong flavor of 3rd /5th

probably not what you are asking about, though.

Sometimes how the note connects with what comes before or after is more important than the relation of the note to the chord

that bears repeating

 

[blakelock]

i think you're asking, why, in general, does a 3rd or 5th sounds good in place of the root. it's because they have simple fractional relationships to the frequency of the root note. the 3rd is ~5/4 and 5th is ~3/2....or something like this. that's why root, 3, 5 make a nice chord when played together.

 

[Gravedigger Dav]

It is probably too basic to mention for the OP,
but 3rds and 5ths come in various flavors
3rds can be major or minor
5ths can be perfect , augmented or diminished.
which 3rd or 5th you favor depends on chord quality
so it's possible to play the wrong flavor of 3rd /5th

probably not what you are asking about, though.



that bears repeating

Good info, but I think the OP, and most any musician, assumes 3 is major and 5 is perfect unless otherwise stated.

 

[Chad T]

i think you're asking, why, in general, does a 3rd or 5th sounds good in place of the root. it's because they have simple fractional relationships to the frequency of the root note. the 3rd is ~5/4 and 5th is ~3/2....or something like this. that's why root, 3, 5 make a nice chord when played together.

Yeah, but sometimes substitutions sound good and other times they just don't. Going by what you are saying, harmonically speaking, a bass player could substitute a 3rd or 5th for the root in every single chord of a song, but nobody does that because it would be confusing and sound bad. I'm just trying to get a grip on the theory of why that is.

 

[electracoyote]

If the next chord is the IV (or iv), playing the third just prior can have a really nice affect. That's a kinda sorta maybe rule that usually works.

 

[Mushroo]

The keywords you are looking for are "inversion," "voice leading," and "counterpoint":

Inversion (music) - Wikipedia, the free encyclopedia
Voice leading - Wikipedia, the free encyclopedia
Counterpoint - Wikipedia, the free encyclopedia

 

[Chad T]

If the next chord is the IV (or iv), playing the third just prior can have a really nice affect. That's a kinda sorta maybe rule that usually works.

I'm working on a song and had a couple 3rd subs and sure enough.....next chord in both instances is the IV.

 

[Dr. Cheese]

If you are talking major and minor choice, the 5th is the safe choice if you are going by ear since the 3rd determines major or minor tonality.

 

[Lanky Tunes]

Those are the chord tones. It will work as long as the tones are right.

Major: 1 3 5 7
Minor: 1 b3 5 b7
Dominant: 1 3 5 b7
Diminished: 1 b3 b5 6
Augmented: 1 3 6 b7
Sus 2: 1 2 5
Sus 4: 1 4 5

Any of those tones should work although the 7ths will be weaker sounding and, in a lot of cases, the 6 is a better choice than the major 7th for major chords.

Quite often the guitars or keys are actually not even playing the 1 of the chord themselves. The 5 is also commonly left out as well. In those cases playing the missing notes will have a different effect than playing the same ones as the guitar or keys.

The real choices you have are join, complement, or clash. All can work to varying degrees.

 

[1stnamebassist]

Quite often the guitars or keys are actually not even playing the 1 of the chord themselves. The 5 is also commonly left out as well. In those cases playing the missing notes will have a different effect than playing the same ones as the guitar or keys.

I think this nails it. It s kind of what I was thinking but trying to figure out how to express. If you play the one of the chord it accents the fundamental of the chord. If you and everyone else are playing an inversion, lets say starting on the the 3 or 5, it will have a different sound and may not have as strong an impact. It may not technically be wrong but may not sound quite right.

 

[smeet]

There's no real theoretical rules about why a non-root chord tone sounds good sometimes and not others. But, a good rule of thumb is that there should be good voice leading. This basically means that a non-root tone is best approached and left by step (half or whole), and preferably without a change in direction of motion.

One of the reasons this works is that a line (bass or otherwise) can heard harmonically or melodically. As long as it is strong in one of those aspects, the other one can be weaker.

Just one way to think about it. Sometimes of course it sounds great to go against everything I just said, but it's still good to think about.

 

[dreamadream99]

The validity of the bass note, when not a root, almost always is related to the next chord.

3 loves to go to 4, sometimes 6.
5 loves to go to 1, or stay on 5.

There are also ascending and descending chromatic reasons, so 3 to flat 3 to 2 works, as does 5 to #5 to 6.

 

[StyleOverShow]

roots & 5ths are base notes, use freely
2nds, 3rds, 6ths, 7ths are color notes, adds chordal flavor. As mentioned above playing 3rd going to 4 leads the listener, a good thing, follow the bass player.

Based on rules, 8 notes, 7 tones, octave 1 & 8. Whole step 1-2-3, half 4, whole step 5-6-7, half step 8. Major scale.

 

[Lanky Tunes]

If you play the one of the chord it accents the fundamental of the chord. If you and everyone else are playing an inversion, lets say starting on the the 3 or 5, it will have a different sound and may not have as strong an impact.

The bassist note choice is actually what makes the chord an inversion or slash chord or anything else.

If everyone is playing root in bass and you stat playing the third then you have made it a first inversion; a fifth and it's a second inversion, ect.

The bass actually has so much control over what is happening in the music, but so many lazy players have regulated it to ust being a lower and dumber version of the guitar.

Sad really.

 

[Chad T]

The bassist note choice is actually what makes the chord an inversion or slash chord or anything else.

If everyone is playing root in bass and you stat playing the third then you have made it a first inversion; a fifth and it's a second inversion, ect.

The bass actually has so much control over what is happening in the music, but so many lazy players have regulated it to ust being a lower and dumber version of the guitar.

Sad really.

Very true. I play guitar as much as I play bass. And that leads to an observation/question from the viewpoint of a guitar player: if there is a slash chord and I know the bass player is going to cover the inversion, then I usually just play the normal chord and let the bass player cover the note substitution. I take it that is fairly normal? Sometimes I do go ahead and play the full slash chord, but some of them (like an A/C#) can be a pain to finger properly.

On the other hand, I regularly play with a guitar player who DOESN'T play bass and he almost always tries to play the slash chord including the inversion. I guess neither is incorrect, but I'm thinking his approach makes some chords unnecessarily complicated and kind of shows lack of understanding of inversions and what the bass player's role is.

Thoughts on that?

 

[Lanky Tunes]

if there is a slash chord and I know the bass player is going to cover the inversion, then I usually just play the normal chord and let the bass player cover the note substitution. I take it that is fairly normal? Sometimes I do go ahead and play the full slash chord, but some of them (like an A/C#) can be a pain to finger properly.

it depends on the purpose of the slash chord.

Often the slash notes are a walking bassline under or over the main chord. Generally, I say that the bass would play the slash notes of the under line and the guitar would play them when they are the highest note (inverted slash chord).

On the other hand, I regularly play with a guitar player who DOESN'T play bass and he almost always tries to play the slash chord including the inversion. I guess neither is incorrect, but I'm thinking his approach makes some chords unnecessarily complicated and kind of shows lack of understanding of inversions and what the bass player's role is.

Thoughts on that?

In all cases the only real rule is this: make it sound good.

A lot of these choices are going to depend on how muddy/grindy you want things to sound. I generally like stuff where the band memebers sort of stay out of each other's sonic space, but there are times to grind things out too.

 

[Chad T]

it depends on the purpose of the slash chord.

Often the slash notes are a walking bassline under or over the main chord. Generally, I say that the bass would play the slash notes of the under line and the guitar would play them when they are the highest note (inverted slash chord).

In all cases the only real rule is this: make it sound good.

A lot of these choices are going to depend on how muddy/grindy you want things to sound. I generally like stuff where the band memebers sort of stay out of each other's sonic space, but there are times to grind things out too.

Thanks. Currently I am mostly involved in P&W music at church and in that setting giving each other sonic space seems to work best most of the time.

On the other hand, I played guitar in an originals heavy rock band a few years ago and we'd take a lot of A string power chords and have me (the guitarist) add the 2nd inversion (5th) on the low E string to add the "heavy". And the bass player usually stuck to the root note on the A string. In that setting, it sounded great. However, now that I have a better understanding of bass (I didn't play bass at all back then), I wish we would have experimented doing it the other way around. i.e. guitar stick to a normal 2 or 3 string power chord and the bass player do the low inversion.