Theory behind the change from a major chord to the same in minor

Question

In many songs I hear the change from a major chord to the same, but minor. For example F A Bb Bbm. It sounds really nice to me and I'm wondering if there is a theory behind it.

Is there a genre where this is used more often? Is there a name to identify this particular chord change? Can you do it with every grade of the scale or in some cases it just doesn't sound good?

Any other info about it is appreciated.

edit: it might be stupid, but I asked the question because of the song
We Are The Crystal Gems - Rebecca Sugar.

Answer 1

This progression immediately reminds me of Creep by Radiohead, though it is in C major, not F major.

While there is no natural key containing F major and A major, these two chords together are very common in most genres, but especially in rock, which loves minor to major substitutions.

D minor is the relative minor of F major, and while the key of D minor natural does not contain an A major, the key of D minor harmonic does.

So we have:

F major F Bb C

D minor Dm Gm Am-->Amaj

In the minor key, this substitution v-->V is extremely common in virtually all genres. Rock will also substitute iv-->IV, and occasionally i-->I (though the last one will definitely jar the key from minor to major.)

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Returning to your question, it is also possible to subsitute major chords with minor chords, though it is less common.

The substitution IV-->iv (in the case of F major Bb-->Bbm) is the most common of these.

What is nice when we see all these chords together, is that the 'odd note' in A major is C# and the 'odd note' in Bb minor is Db. These two notes are enharmonic, which creates a nice symmetry which I am sure enhances the sound of the progression. To me the IV-->iv in the major scale is the analog of the v-->V in the minor scale. A consequence of adding that one more note to the diatonic in order to obtain the latter substitution, is that we also get the former.

It is difficult to pick a genre that regularly substitutes major chords with minor chords.

However the practice of borrowing notes from the minor is extremely common in blues melody. The so called "blue notes" are extra notes, borrowed from the minor, added to the major scale. So in your case in Bb major we get the flat third D-->Db.

In fact in blues, you may find yourself playing these notes (Bb major) over chords in Bb major, or even its relative minor (that is G minor, the minor key with the same notes) over chords in G major.

Answer 2

A common place for this to occur is IV to iv, often then returning to I, which makes (in your F key) the Db a semitone from C, and Bb a semitone from A, both found in the F chord. The F, of course, remains static. It's the same sort of semitone pull that makes V7 work so well as a dominant, to I. 'Major to minor' is one way to describe it. Ironically, in 'Every Time We Say Goodbye' the words go 'major to minor', but the chords go IV-bVII9.

Answer 3

The chord basic progression I - VI - IV - II - V - I has been around almost as long as tonal music. Pop song writers have used it hundreds of times, and so did Mozart. In the key of F, that is F - Dm - Bb - Gm - C - F. Add a few 7ths if you want, of course.

But you can precede almost any chord with its "secondary dominant". The dominant of Dm is A, so F - A - Dm works nicely. In your song, the Dm is skipped to give F - A - Bb. Again that is common enough in classical music (replacing the A - Dm by A - Bb is one version of a so-called "interrupted cadence") - though the voicing as in your youtube link sounds a bit crude to my ears, it's smoother if the bass rises from A to Bb but the other notes of the chord fall rather than rise.

Having got to Bb, again it is a classical ("plagal") cadence to come straight back to the tonic of F. Personally I would consider the Bbm to be more about voice-leading than harmony - it's just filling in the tone D - C with a semitone, D - Db - C. J S Bach probably wrote the exact same progression thousands of times rather than hundreds - there's nothing much new in modern popular music!

In the voice leading, there is also a nice symmetry in the progression C - C# - D - Db - C. "Harmony" and "Counterpoint" are often two sides of the same coin.

Answer 4

It's just a temporary modulation. In jazz and older pop music, this shows up frequently in a progression called "downstep modulation", where you have sequential iim-V7-Is a whole step lower, so for example: Am7-D7-GMaj7 Gmin7-C7-FMaj7, Fm7 ...

Answer 5

There a lot one can do when writing creating a progression to introduce chords that would not necessarily be found in within the same key. In fact, There isn't a key that naturally contains both an F major chord and an A major chord, but I'll focused on the chords you're interested in which is the Bb major and the Bb minor.

For simplicity let's say these Bb chords are used in the key of F major. There are two basic way to view this change which are modal borrowing and chromatism.

The Bbm minor chord can be looked at as you are borrowing from F minor (or F Aeolian) since this chord naturally occurs there. This way you get a little flavor of that mode without changing too much of your overall harmony and it is very, very easy to do. Most songs you listen to now do this without thinking about where the chords come from since it's such a common technique.

The other way is the since you already started on a Bb major chord, you want the next chord to be related, but sound different so you change one note which in this case you move the third chromatically down. This is also very common and in a different example it is how we would logically get from let's just say Bb to Bdim ( by moving the Bb ->B). A good example of this in action is Home Sweet Home.

It's most likely the combination of the two ideas above which is why you like it, and I suggest picking progressions like this apart to see if you can find patterns like this.

Answer 6

As others have stated there is a temporary modulation. But the particular change you are referring to (IV to iv) actually comes from the Harmonic Major Scale. The scale was named by Nikolai Rimsky-Korsakov.

For instance a C harmonic major scale consists of the notes C D E F G Ab B (C). Contrary to the usual (ionian) major scale: C D E F G A B. Some good harmonies come from this scale including the IVm chord you are referring to.

Clearly the fourth triad in the HM scale = F Ab C, which is an Fm chord. Extensions of this are in the form of Fm6 (my favorite addition, try it out), FmM7, FmM7(9) etc...

Answer 7

The main theory idea is borrowed chords where chords from the parallel key substitute chords in the given key. The letter of the chord roots stays the same - its spelling with accidentals can change - but the chord quality changes. Ex. In F major the diatonic chord of the sixth scale degree is vi (D minor) the chord borrowed from the parallel minor is bVI (D flat major) - note that the root is lowered a half step in minor.

But that is just a quick example of how to use the terminology. I think the real question of the OP is why it sounds "good", why is it "effective." I suggest two things:

• "Color." Borrowed chords are chromatic. They introduce more tones creating a richer tonal palette. Typically borrowing is from minor into major. That coloring is often described as "darkening" the sound. To the extent you can ascribe moods to harmony it can be described as dramatic, sentimental, sad, etc.
• The lowered tones of borrowed chords introduce possible half step movements in voice leading and those are especially important in tonal music. Borrowed iv to I is a good example. Plain IV to I involves only one half step movement in smooth voice leading: the fourth scale degree moves a half step down to the third scale degree (the other movements being the sixth degree moving a whole step down to the fifth degree and the tonic being held common.) With the borrowed iv the sixth degree is lowered a half step so then in iv to I the sixth degree move a half step down to the fifth degree.

Two half step movements in voice leading is important. In V7 to I you have two half step movements: the fourth to the third and the seventh up to the tonic. Also, while I'm not really into the idea of negative harmony you can use the concept to think about iv to I as the "negative" (inversion) of V to i. V6 to i has two half step movements of the bottom two voices and iv6/4 to I has two half step movements but of the top two voices.

I think there is some connection between the negative/inverted nature of V6 i and iv I and genre. In V6 i the half steps involve a move to the tonic and in a very broad sense that - establishing tonics/dominants - is the primary concern of "classical" harmony and form. The half step movements in iv I involve the modal degrees - again that is about color and mood - which was less of a concern in classical style. But you really cannot connect modal borrowing with one style. It's found in many styles over the ages. But it think it's safe to say it wasn't a big part of classical style. (Parallel key changes between movements or entire sections yes, but chord borrowing not so much.)

Answer 8

I would rather say that there is no theory behind it but rather a kind of style and a tendency to connect chords in the shortest way possible.

That meaning - every note of a chord has to go to the closest note of the following chord with the least possible resistance -> shortest movement and easy to sing if you see each chord progression as different lines of melodies that happen to (vertically) form chords on their way through time.

So if you consider this as THEORY I can give you some explanation:

The closest note for the the 3rd (D) of your Bb chord (SUBDOMINANT or IV) would be the 5th (C) of the (most likely) following TONICA (root) chord F (F A C).

There is only one way to get closer to your TONICA chord and this is to flatten the 3rd (D) of your Bb chord to a minor 3rd (Db). Now you have the perfect chromatical line in your imaginary melody D - Db - C...

Least resistance - shortest and fastest movement possible ;-)))

Just look what those Jazz-people out there are doing (since the times of J.S.Bach - the grandmaster of them all):

II m7/9 - V 9/b13 - I maj9 - I 6/9
Dm7/9 - G9/b13 - C maj9 - C 6/9

E___Eb__D___D  
C___B___B__(Bb)-A  
A___Ab__G___G  
F___F___E___E  
D___G___C___C  

Or the hardcore version:

II m7/9 - bII b5/b13 - I maj9 - I 6/9
Dm7/9 - Db b5/b13 - C maj9 - C 6/9

E___Eb__D___D  
C___Cb__B__(Bb)-A  
A___G___G___G  
F___F___E___E  
D___Db__C___C  

Chromatic lines all over the place - even in the base line... ;-))) - but of course this changes the style and character of your music. And - of course - the G in the second chord of the hardcore version is actually a double flat A ('Abb')

But would you ever consider Bach to be the greatest 'Jazzer' ? No?
Well then get yourself some Bach-scores and read all the polyphonic lines of his Fugas and Concertos vertically (in chords). This will let Charlie Parker appear as a composer of lightweight children songs. ;-)

But seriously - if you want to learn about real application of chords in music forget about theory-books. They only explain what has already been written long time ago. So listen and compare the scores at the same time.

As once one said: Talking about music is like dancing about architecture!

Go for the real thing. It's already there...

EDIT: And by the way - in the progression F A Bb Bbm - the A chord instead of the usual Am is doing the same. Chromatically progressing line from C-C#-D. And the Bb-Bbm is reversing the same pattern. So you get a nice chromatic melody C-C#-D-Db-C...

By doing -> F F7/#5 Bb Bbm you would get the same C-C#-D-Db-C line. Same principle but different chord progression...

Answer 9

The only 'theory' you need is to get rid of the idea that chords that 'go well together' need to be from the same scale. You can then accept that modifying one note of a diatonic chord is a natural thing to do. If you feel hanging a label on it gives extra validation, try 'Modal Interchange'. But in the case of using iv in a major key this is using a sledgehammer to crack a nut. It's just a very common thing to do in tonal harmony. 'Theory' is a set of descriptions of what has been found to work. Freely moving between IV and iv has long been found to work. Put it in your bag of 'theory' and carry on.

Answer 10

I'm wondering if there is a theory behind it.

Most tonal harmony theories deal with this kind of progression or transformation.

Is there a genre where this is used more often?

This is way common. Any style with non-obvious harmony (with this I mean not only 3 or 4-chord music) will feature some changes like that.

Probably, in your example, we're in F major (with a modulation or tonicization in F minor or Bb minor last chord, depends on context). With this tonal framework in mind, we have plenty tools to begin our analysis. With this kind of transformation, I really like to use neo-riemannian theory as it simplifies these routes harmony takes by generalizing in archetypical operations. With them, you can move from a chord (or key) to another by maintaining common pitches or create a unexpected motion to approximate 2 non related chords, gluing together different tonic regions of pitch space.

The same chord Maj -> min (or vice-versa) is a operation called Parallel (P), as you get the parallel chord. It may occur on every chord on a scale step or borrowed. If you pay attention closely, you see that P's only changes one pitch from the chord: the 3rd. There's other 2 basic operations (change the root or the 5th), but they're off topic here. Google it and you will find this new world of adventures (or nightmares, as the complexity escalates quickly).

Answer 11

The only true theory concept is harmonic function and how a chord generally feel in a particular key (in relation to a tonic basically), in your case FMaj

F (tonic) - A7? - Bb (subdo) - Bbm?

You can actually not play A7 and Bbm cause their function is only to introduce next chords or extend previous chord , they are not rooted in the key, they are additionnal to make the chord progression more interesting and flowing (see jazz)

A7 (or A7b9 to be more accurate) function is to lead to Bb, it work because BbMaj7 is actually Dm/Bb and "A7b9 -> Dm" = "V7 (dominant : tension) to I (tonic : resolution)". Bbm7 function is still a subdominant like Bb, it is a subdominant prolongation. There is no tritone, the Bb note is characteristic of the subdominant function in F major key. The song is then basically a I – IV cadence, moving between Fmaj and Bbmaj.

It does not mean that is the only possibility, any of those additionnal non diatonic chords can be substitute as they are non essential , try Bb7 instead of Bbm7, work great as well and create a function of dominant, and do not have the same notes: Bbm7 notes are in the Bb dorian scale (Bb - C - Db - Eb - F - G - Ab) and Bb7 notes are Bb lydian dom or C Mixo b13 (Bb - C - D - E - F - G - Ab).

Often you have to choose those additionnal chords based on the melody as you dont want any clash with that (meaning weird interval (usually refer to b9 or tritone interval but it depends of personnal taste)), if there is no melody you can do what you want