Jump to content
HAPPY NEW YEAR, TO ALL OUR HARMONY CENTRAL FORUMITES AND GUESTS!! ×

Theory question about chords


Recommended Posts

  • Members
Posted

Hello Everybody!

 

I'm a brand-new member, though I've been enjoying everyone's posts for a

couple years now. (Thank you to all of you, by the way, for the helpful information and reading pleasure!)

 

I'm posting for the first time because a theory question is just niggling away at me. 'Hope one of you terrific music theorists can help!

 

Here we go: In any harmonized scale -- that is, in the seven principal chords

for any given key -- why is it that only these chords are sometimes interchangeable with each other: The I chord interchangeable with the vi chord; the V chord interchangeable with the Vii chord; and the ii chord interchangeable with the IV chord.

 

I understand, of course, that within each of these pairs, the chords share two common tones. But, other pairs of chords in the group also share two tones. For instance, the vi chord shares two tones with the IV chord; the I chord shares two tones with the iii chord; and the iii chord has two tones in

common with the V chord). So why aren't these pairs considered viable substitutes for each other?

 

Thanks, everyone!

 

Joyce

  • Moderators
Posted

The usability of various chords for the purpose of substitution varies by context. My take goes like this:

 

For the I major chord:

The VI min7 works because it uses the same notes as the I maj6 chord

* note that the maj6 is the least dissonant of chord extensions *

The III min will work if you are looking for a I maj7 sound

The III min7 will work if you are looking for a I maj9 sound

 

For the IV major chord:

The II min7 works because it uses the same notes as the IV maj6 chord

The VI min will work if you are looking for a IV maj7 sound

The VI min7 will work if you are looking for a IV maj9 sound

 

For the V major chord:

The III min7 works because it uses the same notes as the V maj6 chord

The VII dim will work if you are looking for a V dom7 sound

* note that as a true substitution the VIIdim chord fails due to a lack of stability *

The VII min7b5 will work if you are looking for a V dom9 sound

* note that as a true substitution the VII min7b5 chord fails due to a lack of stability *

 

In general the concept of using the min7 chord a minor 3rd below a major chord as a substitute is the strongest to defend since this substitution changes the sound of the original chord the least. The min7 substitutions a major 3rd above introduce extensions / tensions that change the sound of the chord.

 

There are also triads substitutions based on the 5th above, the 7th above and the 9th above the root of a major chord - all of which define increasingly more extensions / tensions to the sound of the original chord.

 

The same kind of thing happens with finding substitutes for minor chords. The "best" substitutes change the sound the least. For the adventurous, "borrowed" chords" are another form of chord substitution for exploring.

 

cheers,

  • Members
Posted

 

Hello Everybody!


I'm a brand-new member, though I've been enjoying everyone's posts for a

couple years now. (Thank you to all of you, by the way, for the helpful information and reading pleasure!)


I'm posting for the first time because a theory question is just niggling away at me. 'Hope one of you terrific music theorists can help!


Here we go: In any harmonized scale -- that is, in the seven principal chords

for any given key -- why is it that only these chords are sometimes interchangeable with each other: The I chord interchangeable with the vi chord; the V chord interchangeable with the Vii chord; and the ii chord interchangeable with the IV chord.


I understand, of course, that within each of these pairs, the chords share two common tones. But, other pairs of chords in the group also share two tones. For instance, the vi chord shares two tones with the IV chord; the I chord shares two tones with the iii chord; and the iii chord has two tones in

common with the V chord). So why aren't these pairs considered viable substitutes for each other?


Thanks, everyone!


Joyce

 

 

Jed and Pop already said what I would have said too! When substituting chords, it always boils down to what sounds good. The theory attempts to explain general tendencies. For every rule, there is an example that disproves it.

 

My point is: "experiment freely. don't apply the theory during the creative process because it can cause more confusion."

 

Use the theory help your head understand the sound you're making.

 

Does that help?

 

Welcome to the forum!

  • Members
Posted

In traditional harmony and I suppose basic tune smithing it's about holding off the V chord. I and VI are part of the same tertial stack as are the IV and II. Dallying around on these pairs gives you much more 'music' than simply cycling on I IV V. Also in progressions of this type the II chord will function as a V/V and form the original and most basic of II V I relationships. The II V I.

  • Members
Posted

 

The I chord interchangeable with the vi chord; the V chord interchangeable with the Vii chord; and the ii chord interchangeable with the IV chord.

 

 

 

Well first I'll have to say that I don't agree with you. The I and IV chords are definitely not interchangeable. Why?

 

 

 

In major scale harmony it's all about the 4th. Let's say you're building a C major chord:

 

C E G

 

Now let's add a maj7:

 

C E G B

 

Now let's keep extending it:

 

Cmaj9- C E G B D

 

Cmaj11- C E G B D F...

 

...here's our problem, this one sounds bad. Try this Cmaj7/11 on guitar:

 

1)

2)6

3)4

4)5

5)3

6)

 

Doesn't sound good, does it? It sounds like it's going in two different directions at once. That's because a natural 4th doesn't work as a held note over the tonic. Any other note in the C major scale will work over a Cmaj chord, but that natural 4th just doesn't. And it's the crux of the majority of tension and release in music. So it gives you basically two distinct groups of chords- those with a 4th and those without.

 

Now, I wouldn't think of chords from the same group as "interchangeable". Especially with guitar players this gets confusing. Yes- often you can play, say an Fmaj7 voicing in place of a Dmin7 chord, but what's really going on is you're playing a Dmin9 chord. Make sense? The bass is still playing D, the function is still Dmin, it's still a ii7 chord. In fact you could play an Fmin6 chord there too. It's a different sound but is still useable because over D the function is still a ii7 chord.

 

Knowing these relationships can be a big help in playing and songwriting, as are the traditional tonic, dominant and subdominant relationships. I just wouldn't put too much stock in it when it comes to actually playing the guitar. It may seem like a shortcut for some- "why do I need to learn to play over a IVmaj7 chord if I can just play the same stuff I would over a ii7?" but you still have to know what a ii7 sounds like, the notes in the chord, and how they resolve to the next chord and fit in the sequence.

  • Members
Posted

 

...here's our problem, this one sounds
bad
. Try this Cmaj7/11 on guitar:


1)

2)6

3)4

4)5

5)3

6)


Doesn't sound good, does it?

 

 

So while preparing my "good/bad is subjective and some people might like this voicing" argument, I pulled out my guitar and played it.

 

He's right. It sounds REALLY bad! Live and learn. :-)

 

This one's just awful too:

 

-0-

-4-

-6-

-5-

-3-

-x-

  • Members
Posted

 

So while preparing my "good/bad is subjective and some people might like this voicing" argument, I pulled out my guitar and played it.


He's right. It sounds REALLY bad! Live and learn. :-)


This one's just awful too:


-0-

-4-

-6-

-5-

-3-

-x-

 

 

 

Yeah, dissonance is subjective, but this is really something else. It just doesn't work, it's like oil and water.

 

I don't know a lot about this stuff, but I think that one factor at play is that a natural 4th never occurs in the set of harmonic overtones. I'm sure a google search would explain it better than I could. What's interesting is that same chord without the maj7th is fine (and used all the time), but when you add the maj7th it just doesn't work.

  • Members
Posted

I didn't realize people would have so much to offer on this topic!

I asked the question because I enjoy theory (go figure) and I like figuring things out in general, but I was stumped on this chord question!

 

'Truth be told, I play the flute (mostly rock ballads) not the guitar, but I do chord progressions and rhythm figures on keys (and sometimes guitar) just to round myself out musically. So with harmony, I guess I know just enough to be dangerous -- but you guys are pretty impressive!

 

Well, gotta go and watch Michael Phelps do his thing! Have a great weekend,

everybody!

 

Joyce

  • Members
Posted

 

Yeah, dissonance is subjective, but this is really something else. It just doesn't work, it's like oil and water.


I don't know a lot about this stuff, but I think that one factor at play is that a
natural 4th never occurs in the set of harmonic overtones
. I'm sure a google search would explain it better than I could. What's interesting is that same chord without the maj7th is fine (and used all the time), but when you add the maj7th it just doesn't work.

 

 

I think you're right about the natural 4th...good thing we have the lydian mode!..sharpen that 4 so you have a CMaj7#11 and it sounds great!.

  • Members
Posted

So been playing a long time...and generally can work things out...but i never get it when a chord occurs in a song (a simple song for ex) and it seems out of place, but works...

 

so consider Em, G, Am, C, B

 

all of these are in G (or the rel minor Em) except the B...so why does it work?? i know it does...and i figure songs out all the time that do this...

 

Perhaps someone can now tell me why....some said it here: 'live and learn" Well.....i'm ready for both!!

best

 

Byron123 :)

  • Members
Posted

You mean why is it B instead of Bmin? The theory answer is B is the V7 of Emin. So if your progression repeats you're leading to Emin, and you can always lead to a chord with it's V7.

 

If that doesn't make sense I'll try and explain it better- here's the notes in Bmin:

 

B D F#

 

And here's the notes in Emin:

 

E G B

 

So you have the B staying the same, the D resolving up a whole step, and the F# resolving up a 1/2 step. The 1/2 step resolution is the strongest. But if we change that Bmin to B then we have: B D# F# in which case the D# is moving a 1/2 step as well and is a much stronger resolution. Does that make sense?

 

Another thing to consider is the move from C to B- moving chords in equal steps is always a strong move, especially when it leads to a release later on- it builds the tension.

 

Anyway, it's easy to get bogged down with theory, but the real answer is it works because it sounds good. Music would be pretty boring if everything had to stay diatonic all the time. The best thing to do as a songwriter is what you're doing- learn as many good songs as you can, and when you find something interesting try and figure out what it is, why it is and how to use it, and then file it away in the back of your head. I think of things like this as musical devices, and you pull them out to solve problems or to get from one place to another.

  • Members
Posted

yep

 

if it was a Bmin i had no issue, theory-wise..it was the Bmaj that was not making sense (logically), but making great sense ear-wise!

 

thanks for the explanation...i had figured it was some sort of resolution thing and i saw the change from B+ to Emin involved those two 1/2 steps but could never have explained that well...can play it well though!!

 

best

  • Members
Posted

So been playing a long time...and generally can work things out...but i never get it when a chord occurs in a song (a simple song for ex) and it seems out of place, but works...


so consider Em, G, Am, C, B


all of these are in G (or the rel minor Em) except the B...so why does it work?? i know it does...and i figure songs out all the time that do this...


Perhaps someone can now tell me why....some said it here: 'live and learn" Well.....i'm ready for both!!

best


Byron123
:)

 

In this case B is the V (major V) of the Key of E Minor.

 

Many times we think of scales as being "Keys". This is not really true especially when it comes to the Minor Key.

 

The Minor Key frequently uses many "scales", the Natural Minor, the Harmonic Minor, and the Melodic Minor.

 

In the Natural Minor scale the "Five chord" is Minor, like a Vm, or Vm7 chord. This chord doesn't have a strong resolution to the Im. So, many moons ago the Vm7 was replaced with a V7 (a Major V chord). A V-Im progression ends up being as strong as a V-I progression in the Major Key.

 

Any "V-I" change/progression is known as a cadence. In this V7-Im progression the V7 gives us a strong leading tone, or cadence, resolving back to the Im chord. The leading tone is the M7 note of the Key, this note is present in both the Harmonic and Melodic Minor scales, not the Natural Minor scale.

 

This V-Im cadence is also at the heart of many flamenco tunes. And you've heard in songs like The House of the Rising Sun, Greensleeves, I'd Love To Change The World, and many more.

  • Moderators
Posted

 

You mean why is it B instead of Bmin? The theory answer is B is the V7 of Emin. So if your progression repeats you're leading to Emin, and you can always lead to a chord with it's V7.


If that doesn't make sense I'll try and explain it better- here's the notes in Bmin:


B D Gb


And here's the notes in Emin:


E G B

 

 

You'll have an easier time in general (and attract less fire) if you spell chords based on their harmonic origins rather than using enharmonic equivalents.

 

B minor - B D F#

 

cheers,

  • Members
Posted

Very Helpful... Been playing for years..my ears tell me it works and thats what I play, but never really understood the why. I have been working on the theory thing for the last year or so. Just when I think I am taking the lead (so to speak!) I spot something creeping up on me. Thanks for some very erudite answers.

 

Byron123

  • Members
Posted

 

You'll have an easier time in general (and attract less fire) if you spell chords based on their harmonic origins rather than using enharmonic equivalents.


B minor - B D F#


cheers,

 

 

 

Yeah, that's me showing my self taughted-ness.

  • Moderators
Posted

 

Yeah, that's me showing my self taughted-ness.

 

No problem. I hope you don't mind the gentle advice. The only keys that have a B major chord are the sharp keys of E, B & F# major. One way to determine about chord tones is that to spell any of the fundamental triads (major, minor, diminished or augmented) you can just skip a note name between the root and the 3rd and between the 3rd and the 5th.

 

So for some triad of C you'd use the notes names of: C (skip D) E (skip F) G. Then you can apply the sharps or flats as necessary to sort out the specific notes that match the triad type.

 

D (something) triad has the note names: D (skip E) F (skip G) A

E (something) triad has the note names: E (skip F) G (skip A) B

 

To sort out the sharps or flats, the best thing to do is to study the major scales but until you get that under your belt you can just count up by half and whole-steps. You already know that to move from one note name to the next note name is typically two frets (so that means a whole-step or two half-steps) except between B/C and E/F which are only one fret apart (a half-step).

 

The distance between any note and it's major third is equal to two whole-steps (four frets). The distance between any note and it's perfect fifth is equal to three and a half whole-steps (7 frets).

 

Obviously it makes the most sense in the long run to just learn the 15 major scales but in a pitch you could use something like the above to check your chord spellings.

 

cheers,

  • Members
Posted

 

Obviously it makes the most sense in the long run to just learn the 15 major scales but in a pitch you could use something like the above to check your chord spellings.

 

 

No wonder guitarists get confused! There are at least 5 places you can play C, more than 120 ways to play a C7 chord, we're the only instrument that accepts tab as a means of notation, and there are 15 KEYS but only 12 chromatic tones!

 

What has helped me in learning theory is to think of theory away from guitar, then apply the concept guitar once I understand it. So for me it gets broken in to "what it is" and "how to play it."

 

There are 15 keys because of enharmonic equivalents: Cb (seven flats) and B (five sharps), Gb (six flats) and F#(six sharps), Db (five flats) and C# (seven sharps).

 

It looks far more confusing than it is.

  • Members
Posted

It does help a bit if you enjoy theory for its own sake...almost the way

some people like crosswords or that numbers puzzle -- Sudako, is it called? Of course, theory can be so unnecessarily complex, it's almost laughable. But, understanding it is very empowering.

  • 4 weeks later...
  • Members
Posted

 

What has helped me in learning theory is to think of theory away from guitar, then apply the concept guitar once I understand it. So for me it gets broken in to "what it is" and "how to play it."

 

 

 

That's something I've said many times. I think one of the biggest problems guitar players have is trying to learn or base theory on patterns they learn on the neck.

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...