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Music Theory

Getting to Know Altered Chords Part 7: Altered I

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This is the seventh and final article in a seven part series on altered chords. In the first part I explained that by lowering or raising a tone of a chord by a half step you can change the color and even the function of a chord.

Part 1 looked at altered V chords, Part 2 at altered II chords, Part 3 at altered VI chords, Part 4 at altered III chords, Part 5 at altered VII chords, and Part 6 at altered IV chords.

We will now wrap up the series by exploring various ways to alter the I chord.

Diatonic I

The first diatonic chord in a major key is a major triad. Pretty self explanatory, in the key of G it's G major. If you add the seventh (a major seventh above the root), you get a major seventh chord (maj7).

It's harmonic function is considered a tonic chord. In an earlier tutorial called The Basic Functions of Harmony, I explained that a tonic chord is home. It's where we feel most at rest, and is usually the starting off and ending point of a song.

I don't think I need to go into much more detail explaining the I chord, so let's get right into the alterations.

Altered I

The more common alterations of I include:

  • I7
  • #Idim7
  • Major to minor, or the other way around

Altering Each Chord Tone

As explained in the previous tutorials, a chord is "altered" by lowering or raising one or more chord tones by a half step. Since there are four pitches in a maj7 chord that gives us four choices for tones to alter, 1 3 5 7.

We'll go through one chord tone at a time and examine the results of altering each of them.


Altering the Root

Lowering the Root

As we've seen before, lowering the root of a major seventh chord just turns the root into the seventh. Rather than an altered I, the chord turns into iii with it's 5th tone in the bass:

It's a nice smooth progression, but it is a different chord, not an altered I.

Raising the Root

Raising the root of the I chord changes it's function. The root is the tonic of the key, and so if it changes we aren't using the tonic anymore, and thus we aren't "home".

When we raise the root by a half step, we get a diminished triad.

The most common way to treat this chord is to use it as a way to pass from I to ii, using the chromatic rise in the root as a guide. It has an old-fashioned "tin pan alley" kind of sound to it. I've added the seventh, turning the chord into C#m7b5.

If we want to get fancy and technical, you can think of that chord as V7/ii in first inversion with an added 9th. I'll explain.

In the key of C V7/ii would be an A7 chord, A C# E G. Our version is C# E G B, or A9 without the root:

What you call it doesn't have anything to do with how it sounds, but this helps explain why there is such a strong tendency to resolve to ii instead of any other chord. Read up on secondary dominants for further explanation.


Altering the Third

Lowering the Third

Lowering the third of a major chord changes it to minor, which is a significant change in it's color and feeling. One of my favorite musical moments of all time is in Beethoven's Moonlight Sonata, when he has modulated to the key of E but shortly after changes the harmony to Em.

The effect is haunting and tragic!

Here is a piece I wrote that is based on only two chords, Imaj7 and Im7. By lowering the third and seventh by a half step I change the chord from maj7 to m7. Oscillating between the two chords creates a whimsical effect, like the music can't decide if it's happy or sad.

Raising the Third

In a major key, raising the third would give us a sus4 chord. This could be used sort of like a plagal cadence. A proper plagal cadence is IV to I:

But Isus4 to I has a similar effect:

Another way to use a sus4 chord is for it's ambiguity, which can be especially effective in film music. If you need to write a cue that is neither explicitly positive or negative, but more neutral, the sus4 chord can be a good solution.

Raising the third in a minor key changes the chord from minor to major. In classical music (or far more often Baroque) ending a minor key piece on a major triad is called using a Picardy Third. The effect is ending on a positive note, even if the key of the piece was sad!

Nowadays if you use a Picardy Third it is usually with a sense of humor, because of how old fashioned it sounds.


Altering the Fifth

Lowering the Fifth

Lowering the fifth of a major triad is a pretty uncommon thing to do. Except for perhaps changing the color for an interesting effect, it's not something that has much functional use in the context of a progression.

Raising the Fifth

Raising the fifth gives us an augmented chord, which can be more useful.

Similar to how raising the root makes a transition to II, raising the fifth creates a nice chromatic passage from I to IV, with the +5 resolving into the third of the IV chord.

Augmented chords are often accompanied with a lowered 7th, making them altered dominant chords. So you might think of it as V+7/IV.


Altering the Seventh

Lowering the Seventh

Lowering the seventh of a major 7 chord makes it a dominant 7 chord. You can either think of it as V7/IV, or if it still feels like a tonic chord you can just call it I7.

Basic blues and early rock styles will often use a dominant form of I IV and V.

The effect is a mixolydian sound, which feels more open and lighter than standard major.

Raising the Seventh

Raising the seventh of a major seventh chord is essentially meaningless because you just end up back at the root again!


Conclusion

Well, that's it for the altered chord series! I hope you've enjoyed reading it as much as I've enjoyed writing it, and have seen the amazing possibilities for color and movement available to you by just making a few tiny tweaks to the standard diatonic toolbox.

Please leave your comments and questions below, either about this particular article or the series in general. Did you like the series? Do you want to see more articles like this, on similar or related topics? Let us know!

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