Reharmonization - Yesterday

Yesterday is a song from The Beatles' Help album released in 1965. Although the song is credited to Lennon/McCartney, the song was written solely by Paul McCartney (from Wikipedia). This is a song in the form of AABA, and partly uses Melodic Minor scale as well as Diatonic scale.

Let's look at the original chord changes first. Here are the original changes transposed into the key of D. (hear) (The original is in F.)

And these are the reharmonized changes. (hear)

Let's look at the first 3 bars of the original changes. (hear)

This tune's key is D major, and the first chord seen above, D, is the I chord (pronounced one chord) of the key. Thanks to the I chord, the tune begins with the D major feel, but it soon sort of drifts into its relative key, which is B minor. This shift to B minor is temporary and I wouldn't call it modulation, but it does generate the "minor" feel for the moment.

Notice that there are two accidentals in the melody, in the second bar. Those accidentals are there to form B Melodic Minor scale. The definition of the Melodic Minor scale is that the last two notes of the Natural Minor scale are raised by half step. B Natural Minor scale consists of B, C#, D, E, F#, G, A. To make this B Melodic Minor, we need to raise the G and A by half step. G into G# and A into A#. Hence, we are seeing G# and A# in the melody above. Melodic Minor scales sound smoother than Natural Minor when ascending.

Let's look at the reharmonized changes for the same bars. (hear)

The first chord D was replaced by D69. This is a simple addition of available tensions. In the second bar, C#m became C#m7 and F# became F#7(b9). Again, these are simply tension-adding, according to the key. I like the use of F#7(b9). If you look at the melody, the note changes from G# to A# when the chord moves from C#m7 to F#7. And, since the G# would be the natural 9th (as opposed to b9) note in an F#7 chord, you might want to have F#9 instead of F#7(b9). F#9 is a fine choice too, but F#7(b9) is also good because by the time the tune reaches the F# chord, the melody's G# note has moved on to A# already. Therefore the fact that G# is the "natural" 9th in an F#7 chord doesn't affect us. Plus, by having F#7(b9), we are creating contrary motion. The G# contained in C#m7 moves "down" to become G natural which is a part of F#7(b9), while the G# contained in the melody moves "up" to become A#. Contrary motion is often nice in composition.

And in the third bar, we have an extra chord which is Ab7. To see what it does, we need to look at the next bar too. So let's shift our focus into the bar 3-4 region. Here are the original changes in the 3rd and 4th bars. (hear)

And here are the reharmonized changes. (hear)

First, let's note that there isn't much reharmonization applied except for the addition of Ab7 here. Bm7, GΔ7 (pronounced G major 7) and A13 are all diatonic chords. So let's focus on Ab7. That Ab7 is analyzed as a SubV/IV (sub-five of four). It creates gravity towards the next chord, GΔ7. And this "SubV/IV" is a Substitute Secondary Dominant chord. Substitute Secondary Dominant chords are the chords that are placed as a substitute for Secondary Dominant chords. So what are Secondary Dominant chords?

Secondary Dominant chords are the dominant chords that are supposed to resolve to any diatonic chord except I. This tune is in D major, making D as a I chord. So if you see an A or A7 chord, it's a Primary Dominant chord because it resolves back to D. But if you see chords like B7, C#7, D7, E7 or F#7, they're Secondary Dominant chords because they are supposed to move to a diatonic chord other than D.

Now, that Ab7 in the first bar above is a substitute chord for D7. In this tune's context, D7 would be a Secondary Dominant chord which is supposed to resolve to G or GΔ7 or any other variation of the G chord. Why do we want to substitute one chord with another? Because it creates a certain kind of "out-ness", if you will. It sounds somewhat "wicked", or interesting. The second chord in this audio (hear) is the Ab7 in question. Compare that with this version (hear) having D7 instead of Ab7.

Let's move on to the bar 4-5 region. Here are the original changes. (hear)

And here are the reharmonized changes. (hear)

Let's look at the C9. That would be a big "?" chord if you are new to reharmonizing. What it is is a Modal Interchange chord derived from the parallel minor key. A parallel key is a key that has the same root, but different modes. This tune is a D major tune, so the parallel minor is D minor.

Now, let me explain Modal Interchange here. As the name suggests, it means interchanging (exchanging) of chords between different modes. And a "mode" means a certain "figure" of a scale. For instance, let's take the C major scale, which consists of C, D, E, F, G, A and B - seven notes. Because the C major scale has seven notes, it can have seven different "modes" depending on where you start seeing the scale. If you start counting from C - like C, D, E, F, G, A, B and back to C (hear) - you have an "Ionian" mode, which is more commonly known as the "major" mode. But if you start from A - like A, B, C, D, E, F, G and back to A (hear) - then you have an "Aeolian" mode, which is more commonly known as the "minor" mode. Notice the difference of mood between the two modes in the audio.

So that's what modes mean. Now what about Modal Interchange? We are in the key of D major for this tune, so, using Modal Interchange technique, we can borrow some chords from the parallel minor key, which is D minor. The key of D minor has the notes of D, E, F, G, A, Bb and C. And as for the chords, we have Dm, Edim, F, Gm, Am, Bb and C as triads, and we have Dm7, Edim7, FΔ7, Gm7, Am7, BbΔ7 and C7 as 7th chords.

Let's look at the reharmonization again. (hear)

The C9 chord in the second bar is a variation of C7, with an addition of tension 9. And C7 comes from the key of D minor. Thus, the C9 is a Modal Interchange chord derived from the key of D minor.

Let's move on to the bar 6 and 7. Here are the original changes. (hear)

Before we discuss the reharmonization, let's note that there's a nice use of Secondary Dominant chord in the first bar, which is E. This
E is supposed to resolve into A, and this makes the E a Secondary Dominant chord. (Remember, the dominant-quality chords supposed to move to any diatonic chord other than I are called Secondary Dominant chords.) But instead, it goes to G. This is called Deceptive Resolution.

And now, here are the reharmonized changes. (hear)

First, I gave up the nice deceptive-resolution effect and recalled the A chord in the beginning of the second bar. But I wanted the same kind of sound as I would have with G, so I put A9sus. A9sus really is like G/A (pronounced G on A). The only difference between A9sus and G/A is that A9sus contains one more note, E. But that note, being a perfect 5th above the root, is strongly present in the overtone series, so this doesn't make much difference.

Then I put F#/D and A7(b9) where it was just D. The melody moves up from D to F# right before we would go to D in the original changes. This creates a chance for us to add the major 7th note to the D chord, because the F# note doesn't interfere with DΔ7 at all, whereas, if the melody stayed on D, that D would cause a problem with DΔ7. The reason for that is because the melody's D could be placed just a half step above the major 7th note of DΔ7, which can often make an uncomfortable sound. So, with the melody moving into F#, I went right ahead to put DΔ7 there, but then I thought I needed more creative edge. Now, one of the cool things that jazz musicians do when ending tunes is that they play some kind of augmented chords such as +7 (augmented 7) or +Δ7 (augmented major 7). And I thought I'd put D+Δ7, whose another name is F#/D. The chord which follows it is A7(b9). This is nothing fancy - just a V7 chord of the key - although it has the tension b9 which is not diatonic.

Then the tune goes back to the beginning, to play the A section (the letter A in a rectangle) again. And then this time, it goes into the 2nd ending (the bracket saying "2") to proceed to the B section.

As you see, the B section begins with the C#m chord. And I wanted to do something so I could connect the end of the A section (which is the 2nd ending) and the B section smoothly. Here's the part in question. (hear)

Let's look at the reharmonization of this part. (hear)

First of all, we see the C#Ø chord in the second bar. That chord signature is pronounced either C# minor 7 flat 5 or C# half-diminished.
It can also be written as C#m7(b5). The first chord is A9sus about which I explained several paragraphs back. And the second chord is the chord I installed to make a nice transition into the B section. The chord is D9, and it's analyzed as a SubV/VII (pronounced Sub five of seven) chord. I wanted to make some kind of dominant motion when the chord moves to C#Ø. In order to make a basic dominant motion, you need to place a dominant 7th chord whose root is a perfect 5th above the target chord's root. Here, our target chord is C#Ø, so you need to put G#7 in front of C#Ø. Furthermore, you can "substitute" that dominant 7th chord by replacing it with a dominant 7th chord whose root is a tritone away from the original chord's root. In this case the substitute chord will be D7. (D is a tritone away from G#.) Therefore, the D9 we see above, which essentially is D7 with an added tension, is a substitute dominant 7th chord (also called SubV) going toward C#Ø. And, since C# is the VII (seven) in the key of D, we call that D9 a SubV/VII (Sub five of seven).

Let's move on to bar 9-10. Here are the original changes. (hear)

And here are the reharmonized changes. (hear)

The first chord changed from C#m to C#Ø. Again, C#Ø is C#m7(b5), so that tells us that we added the 7th note to the original C#m chord and then flattened the 5th note. The flattening of the 5th was possible because the melody didn't reside on the 5th. Instead it's on the 11th of C#m, which is F# as you can see. The flattened 5th is G natural and it has a risk of crashing with the F# of the melody, but you can avoid that by placing the G natural in the chordal voicing an octave lower than the melody's range.

The second chord changed from F# to F#7(b5). I wanted to add an extra spice there. The melody, again, is on F# which is now the root of the chord of the moment, so I could alter the other chord tones as I liked. The flattened 5th in this F#7(b5), by the way, creates a tritone interval with the melody note. (C natural and F# are a tritone away.) This produces a high degree of tension. I knew I was moving into a relatively "safe" chord (Bm7) on the next change, so I thought I'd to take a chance here.

Let's move on to bar 10-12. Here are the original changes. (hear)

And here are the reharmonized changes. (hear)

I made a bold move here. This 3-bar phrase was to end with a D chord in the last bar, and I knew I would stick with that. I replaced D with DΔ7(13) (pronounced D major 7 thirteen), but those two are basically the same, at least function-wise. And, just like the previous Bm7 chord, this is the "safe" chord, which allowed me to venture before it. So, what I did was I placed three continuous dominant 9th chords in front of DΔ7(13). I took this idea from what I read about Debussy. He said something about his use of "floating chords" - chords which don't function in conventional ways. I can't quite remember what exactly those chords were or in what context he used them, but the notion of having chords that are "floating" have stuck with me ever since I read about it. And I tried the idea here. Those G9, F9 and Eb9 don't function in any conventional ways whatsoever. They are just there to sort of fill the time between the two safe chords.

Bar 13-14 are the same as bar 9-10, so we'll skip this.

Let's move on to bar 15-16. Here are the original changes. (hear)

And here are the reharmonized changes. (hear)

Bar 15 takes the same approach as bar 11. They are "floating" chords. And in bar 16, I decided to put some kind of D chord (functioning as I) for the first 2 beats and some kind of A chord (functioning as V) in the last 2 beats, because the next bar holds the D chord too. So, what I came up with as I chord is E/D (pronounced E on D), and what I came up with as V chord is Gm6/A (G minor 6 on A).

Let me begin with explaining E/D first. This means "E triad with D as bass". As you can see on the left, the notes in E triad are B, E and G#. Let's analyze each of those E triad notes in terms of D chord. B would be the 6th (or 13th), E would be the 9th and G# would be the #11th in a "D something" chord. Also, since the D chord here is a I chord, we're most likely to see a D major chord here, as opposed to D minor or D dominant. Therefore, we can say E/D is an alias for D69(#11) or D69(#4). I personally feel the both names are fine, but some people might argue that you can't have #11 without presence of the major 7th note, which we don't have in this case. I think it's a matter of opinion, though.

Let's look at Gm6/A. This chord is the same as A7sus(b9), pronounced A7 sus flat 9. If you look at each note from the top, G is the 7th against A, E is the 5th, D is the sus and Bb is the b9. Therefore we have A7sus(b9). Whether we call it Gm6/A or A7sus(b9) is completely a matter of choice.

The rest is the same as the beginning part of the tune, except at the very end. But that last chord, DΔ7(13) is simply a D chord with added diatonic tensions. Unlike typical pop songs of the era, this song ends with the melody at the 3rd note of the key, versus the 1st. This enables us to add the major 7 without hesitation. If the melody ends at the 1st note of the key, which in turn is the root of the last chord, then we would be safer to add the tension 6 instead of major 7. As I mentioned earlier in this analysis, the major 7 has a risk of crashing with the melody at the root, depending on its placement.