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Chord Transformations: Add, Extend, and Alter

Let's take these one at a time...

Add Chords

To make an "Add Chord", we simply add an extra Note to a Major or minor Triad from its corresponding Scale. There are three different types of Add Chords, and each of them is named after whichever Note is crammed inside of the same Octave as that Triad:

• An "add2 Chord" adds the Note from the 2nd Scale Degree.
• An "add4 Chord" adds the Note from the 4th Scale Degree.
• An "add6 Chord" adds the Note from the 6th Scale Degree.

For example:

Cadd2 [C-D-E-G]
Cadd4 [C-E-F-G]
Cadd6 [C-E-G-A]

Here, the Notes that make each of these an Add Chord are highlighted in a different color.

Upper Extensions & Extended Chords

"Upper Extensions" (also sometimes called "Tensions") are Notes that we use to extend the size of a Chord past the Seventh, thus making it into an "Extended Chord". To reiterate: If we stack Notes a Third away from the highest Note within a Seventh Chord, then we can get the "9th", "11th", and "13th" Extended Chords.

These names come from the Interval that is formed between each of these Notes and the Root of the Chord. Any Interval that is larger than an Octave (like the 9th, 11th, and 13th), is called a "Compound Interval". For example:

Octave + Second = Ninth
Octave + Fourth = Eleventh
Octave + Sixth = Thirteenth

To easily find a Compound Interval, move the bottom Note of the Interval one Octave up. The two Notes now form a smaller Interval that should be easier to recognize. Remember, the name of an Interval comes from how many Note letters that it encompasses. For example, a Ninth (like from C to the D that is one Octave up) spans nine letters, C-D-E-F-G-A-B-C-D. We don't have to try to count these out though! There is an easier way to find them...

You might have noticed that when we covered the Major Scales, we put little numbers in parentheses next to certain Scale Degrees, like this:

1 2 (9) 3 4 (11) 5 6 (13) 7

Here, we have highlighted the numbers in red. These numbers show that the Notes on the 2nd, 4th, and 6th Scale Degrees can become our 9th, 11th, and 13th Scale Degrees when they are stacked on top of a Seventh Chord.

Therefore, we could make a "Thirteenth Chord" that literally contains all of the Notes of the corresponding Major Scale. They are the same Notes, just in a slightly different order. There is nothing extra to remember!

For example, here are the 9th, 11th, and 13th Upper Extensions of a Major Seventh Chord:

CM7 [C-E-G-B]
CM9 [C-E-G-B-D]
CM11 [C-E-G-B-D-F]
CM13 [C-E-G-B-D-F-A]

Notice how these Extended Chords are different from the Add Chords, even though they both use the same Notes. Instead of clustering the Notes near the inside of a Triad like we did with the Add Chords, we spread the Upper Extensions out on top, above the Octave that the Seventh Chord is played in.

Sometimes the terms "add9", "add11", and "add13" are used when people are actually referring to an Extended Chord. Please do not get these two concepts confused! They are different. Extended Chords are always built on top of some kind of Seventh Chord. Any type of Seventh Chord (Major, minor, Dominant, etc.) can be used as a base. But if there is no Seventh, then it is probably an Add Chord, no matter where the extra Notes might show up!

Altered Chord

Another way to change the sound of a Chord is to make the Chord Tones either Sharp or Flat. Whenever we alter the Chord Tones in this way, it becomes an "Altered Chord". We can do this with the Upper Extensions as well:

• The 9th can be either Flat or Sharp.

• The 11th can only be Sharp (because a "Flat Eleventh" is equivalent to a Compound Third, so a Note already within the Chord is simply repeated).

• The 13th can only be Flat (because a "Sharp Thirteen" is equivalent to a Compound Seventh, so a Note already within the Chord is simply repeated).

Sometimes Borrowed Chords, like the ♭III, ♭VI, and ♭VII of the Aeolian Mode (or the Parallel minor Key), are called "Altered Chords". Notice that the Root Note of these Chords is a Half-Step lower than Chords built off of the same Scale Degrees within the Parallel Major Key. That is why the Roman numerals are preceded by a ♭.

Whenever a Chord contains a Note that is outside of the Key that we are in (i.e.: it has Chord Tones that are "Non-Diatonic" or "Chromatic"), it is generally referred to as a "Chromatic Chord". Therefore, there is often some overlap between the terms "Non-Diatonic", "Chromatic", and "Altered" when it comes to Chords.


Like the use of Chromatics within a Melody, these three concepts (Add Chords, Upper Extensions, and Altered Chords) can be sprinkled throughout our Harmony to "add some color". [If you are wondering when you will ever use these Tone Clusters and absolutely massive Chords, some genres of music (like Neo-Soul) use them a lot. The general rule of thumb is that the wider variety of Intervals that a Chord has, the more "lush" the sound. Mangold Project has a video that demonstrates this principle well.]

The following pages present all of the information that we need to easily utilize the above three concepts...