Altered Chords

I assume at this point that you understand conventional (tertian) chord construction. If not, please review the following lessons:

constructing triads -
Constructing 7th chords -
Constructing extended chords -

Recall from lesson on building a context that we've defined a chord as being 3 or more distinct notes, usually played at the same time. (C and D are considered distinct, but C# and Db are not, nor are octaves of the same note).

Without getting into a historical discussion, let's review naming conventions for chords.

Recall, A major chord is written using the letter-name only.
e.g. C = C major
major chord = 1,3,5.

* note: if there are no other letters in the chord (after the 1st one), then the assumption is that the chord contains the root, major 3rd, and perfect 5th (more on this later).
(More on major chords at

A minor chord has the letter-name followed by a lowercase m.
e.g. Cm = C minor
minor(m) = 1,b3,5

* note: We assume when we see an "m" in the chord that it contains the minor third , and perfect fifth, unless we are told otherwise.
(More on minor chords at

Augmented Chords have the letter-name followed by a plus sign (+).
e.g. C+ = C augmented
augmented (+) = 1,3,#5

and we assume if we see a plus sign directly after the letter-name that the chord contains a major third, and an augmented fifth.
(exceptions follow below)
(More on augmented chords at

Diminished chords have the letter name followed by a degree sign (o) in superscript.
e.g. Co = C diminished
diminished (o) = 1,b3,b5

And we assume if we see a degree sign after the letter name that the chord contains a minor 3rd, and a diminished 5th.
(More on diminished chords at

Suspended chords have the letter name followed by the letters/word "sus", and perhaps a number.
e.g. Csus4 = C suspended 4th.
Csus2 = C suspended 2nd
* note: Csus = Csus4
sus4 = 1,4,5
sus2 = 1,2,5
and we note here that it is the 3rd which is suspended to/from the 4th or 2nd.

We can view suspended chords as altered chords. We can say to ourselves that we take the 3rd of the chord and move it somewhere else (close by). 3rd are not the only notes that can be suspended; we will see other notations later.

but there is a chord that throws some people, and seems to disobey the rule, and that chord is m7sus4.
m7sus4 = 1,b3,4,b7
(here the 5th has been suspended to the 4th).
7sus4; however, obeys the usual convention when seeing sus that the 3rd has been moved to the other note
7sus4 = 1,4,5,b7

(More on suspended chords at

Add chords have the letter-name and the "add" and a number (or possibly a note name.)
e.g. Cadd4 = C major w/ an added perfect 4th.
Cmadd9 = C minor w/ an added major 9th.
CaddF = C major w/ an added F note.
add4 = 1,3,4,5
add9 = 1,3,5,9
madd9 = 1,b3,5,9
Here we take whatever typ of chord we have and add the particular interval or note to it.
(More on add chords at

Common extensions.

Six chords have the letter name and then 6 after the name.
e.g. C6 = C six
Cm6 = C minor six
Co6 = C diminished six
6 = 1,3,5,6
m6 = 1,b3,5,6
o6 = 1,b3,b5,6
Here simply writing a 6 after the chord name adds a major sixth to it.
* note: to show a minor sixth (interval) added instead of a major sixth, put a flat in front of it. (more on flats below).
Cmb6 = C minor - minor sixth
mb6 = 1,b3,5,b6

(More on six chords at

Dominant Seventh Chords can be written either with the letters "dom" and a 7, or with just a 7 (after the letter name)
Cdom7 = C7 = C dominant seven
7 = 1,3,5,b7
And we assume where we see a 7 by itself (no other letters or symbols beside the root name), that we are adding a minor seventh (interval) to the previous chord.
Cm7 = C minor seven
m7 = 1,b3,5,b7 (like m, with an added minor seventh)
7sus4 = 1,4,5,b7 (like sus4, with an added minor seventh)
C+7 = C augmneted seven
+7 = 1,3,#5,b7 (like +, with an added minor seventh)
There is an exception for diminished 7ths (see below).

(More on dominant seventh chords at
(More on minor seventh chords at

Major seven chords can be written with a capitol M in front of the 7, a delta in front of the 7, the letters maj in front of the 7, or a 7 with a line through it.
e.g. Cmaj7 = CM7 = C&del;7 = C7 = C major seven
maj7 = 1,3,5,7
maj7sus4 = 1,4,5,7
We assume if we see a delta, maj, or a line through the number that there is a major seventh in the chord
Cmaj9 = C major nine (contains a major ninth in it)

(More on major seventh chords at

Diminished Seventh Chords
Earlier we said if we see a 7(directly after the chord name) then there is a minor seventh in the chord. The exception is the diminished chord (with the degree sign).
Co7 = C diminished seven
o7 = 1,b3,b5,bb7
The diminished seventh interval (bb7) is enharmonic to the major sixth (bb7 = 6)
C_7 = C half-diminished seven
_7 = 1,b3,b5,b7
note: to show the minor seventh interval after the degree sign, a slash is placed through the degree sign.

(More on diminished seventh chords at
(More on half-diminished seventh chords at

MORE EXTENSIONS (9's, 11's, 13's)
(More on extended chords at

9th chords
Whenever the 9 is the first number written down in the chord, it means that you add a major ninth to the corresponding 7th chord {assuming no "add", "sus", (), or /}.
e.g. 7 = 1,3,5,b7
9 = 1,3,5,b7,9
m7 = 1,b3,5,b7
m9 = 1,b3,5,b7,9
maj7 = 1,3,5,7
maj9 = 1,3,5,7,9

11th chords
Whenever the 11 is the first number written down in the chord, it means that you add a perfect eleventh to the corresponding 9th chord {assuming no "add", "sus", (), or /}.
e.g. maj9 = 1,3,5,7,9
maj11 = 1,3,5,7,9,11
etc. ...

13th chords
Whenever the 13 is the first number written down in the chord, it means that you add a major thirteenth to the corresponding 11th chord {assuming no "add", "sus", (), or /}.
m11 = 1,b3,5,b7,9,11
m13 = 1,b3,5,b7,9,11,13
dom11 = 1,3,5,b7,9,11
dom13 = 1,3,5,b7,9,11,13

Slash Chords
Chords with a slash in them can mean a couple of things. We will consider them one-at-a-time.

Chords with a slash, then a note name
e.g. E/G#
play the chord before the slash, and play the other note after the slash "in the bass" (as the lowest note in your chord).
Our example E/G#, play an E major chord with G# in the bass.

Chords with slash and then a number
e.g. C6/9
Play the chord before the slash, and add the extension after the slash. Our example says play a C6 chord with an added 9th.
6/9 = 1,3,5,6,9
m7/11 = 1,b3,5,b7,11

Chords with slash and then another chord.
e.g. E5/G5
play 2 chords at once. play the chord to the left of the slash on top of the chord to the right of the slash. this is an example of bitonality (polytonality).
the chords could be split between multiple players.
e.g. B5 = X244XX
G5 = 355XXX
(the above has practical application in playing a Gmaj7 with heavily distorted guitars yet sounding clean.

(More on slash chords at

CHORDS WITH ACCIDENTALS (sharps, flats, naturals)

When the accidental is directly after the letter
e.g. C# this example is the C# major chord.
(* note: it is bad form to write the accidental directly after the letter for anything but to indicate thye root note of the chord)
C#5 = 1,5 (in C#), not 1,#5

Accidental occurs after a number (when 2nd number is part of earlier chord
e.g. C7#5
7#5 = 1,3,#5,b7
m7b5 = 1,b3,b5,b7
Here the 5 is part of the 7 or m7 chord already, but instead of playing the perfect 5th, we are playing an augmented 5th (#5), or a diminished 5th (b5).

e.g. Dm7#11
m7#11 = 1,b3,5,b7,11
here #11 is not part of a 7th chord. So we add the other extension (#11) to the earlier chord (m7).


Plus signs
A plus sign before a number means the basic triad is an augmented chord.
e.g. D+7
+7 = 1,3,#5,b7

a plus after a number, before a second number, indicates that you add (or alter) an augmented interval.
e.g. 7+5 = 1,3,#5,b7
7+9 = 1,3,5,b7,#9
maj7+11 = 1,3,5,7,#11

Minus signs (dash)
A minus sign after the letter name is often used in jazz to represent a minor seven qualities (b3,5,b7). It is most often seen in two forms e.g. C-7 = Cm7
Here the -7 works just like m7, and this is the most commonly use of the dash.

The second most common usage is by itself
e.g. C-
This is slightly ambiguous. Not uncommon in jazz heads, various sources have cited it as
C- = C-7
C- = Cm
C- = Cm, Cm7, Cm9, Cm11, Cm13 ( any appropriate extension).

(* similar ambiguities arise with other chords such as Cmaj, Co, Cdom).
{in practice, many jazz musicians interpret extensions that aren't written down}.

If you're using - to write a chord down, it would be better to write C-7 for Cm7, than to write C-, but if you want to be more open to interpretation, then you could use C-.

Another use, not commonly seen, is with "sus".
e.g. Csus4-3
means have the Csus4 chord resolve the 4 to the 3, (again, not common)

(*note: an old mel bey book lists x- as being a diminished chord. This is the only reference that i've seen with such. Other references list it as a minor chord. the same mel bey book lists -9 as being m7b9.)

parenthesis can be used to represent an added note, a suspended note (other than the 3) or an altered note.

added note with parenthesis
e.g. C(#6)
Here C#6 and C+6 would mean something different:
C#6 = 1,3,5,6 (in C#)
C+6 = 1,3,#5,6 (in C)
C(#6) = 1,3,5,#6 (in C)

Suspended note with parenthesis
e.g. C(4)
Here the 5th has been suspended to the 4th.
C(4) = 1,3,4 (in C)

Altered notes with parenthesis
e.g. Cm(#5)
Here the 5th of the chord has been altered.
Cm(#5) = 1,b3,#5

Parenthesis with "omit" or "no"
omited notes.
e.g. Dadd9(no3)
add9(no3) = 1,5,9
add 9 = 1,3,5,9

Notice the add9(no3) has the same notes as the add9 except the "omited" note, the 3. There are several reasons for such chords (see below)

"no" works the same way
D9(no5) = 1,3,b7,9 (in D)
9 = 1,3,5,b7,9
In practice, we probably already know patterns for chords, and which notes are which intervals in those chords, and we choose to remove the omited intervals from those shapes.



Why use altered chords?
There are several different reasons for altered chords, but the simplest reason is efficiency. For practical reasons it is easier to deal with alterations than to give a unique name to each possible comination of notes.

the number of combinations of notes within one octave (irregardless of key)is over 2100. Multiply that by 12 if you want to deal with keys. Add more if you go outside an octave (if 2 is treated differently from 9, etc.) (number increases significantly), multiply by several times for inversions/voicings/different places on fretboard. {if you feel overwhelmed it's good to remember there are only 12 tones}. you see chord books claiming 20,000 chords (sounds impressive, but there just aren't that many discrete chords).

So, aside from why we use altered notations (#,b,no,omit,add,sus,+,-,etc.) we can ask where do these chords pop up and why. We will consider two main causes.
Chords as alterations (syntheticly created)
Chords as pure sounds

Chords as alterations (Synthetically altered chords)
Sometimes a composer/player may decide to take a chord and change 1 or more notes in the chord.
e.g. playing V7#9 instead of V9 (for effect)

* iii7b9 would not be (syntheticly) altered in the major scale/key because that chord naturally occurs there. (iii9 would be syntheticly altered in the same situation, though no alteration appears in the name.)

It's important to understand how scales are harmonized and what chords arise on which degrees, etc. (synthetically altered chords are often used to increase tension).

Chords as pure sounds
More often than taking some chord and altering it, the chord is some pure sound that had to be notated somehow, and it was most convienient to write it out as an alteration of another chord than to write a different symbol for each possible chord. It's important to note that our names for chords are not necessarily connected to how chords are created.

A popular misconception about chords (and scales) is that they are created from the major scale. This is almost never true.

Let me clarify.

The major scale can be expressed as
major scale = 1,2,3,4,5,6,7
This is short-hand notation describing the kinds of intervals (measured from the tonic) found in the major scale.

Now, the maj7 chord : maj7 = 1,3,5,7
and this can be created from the major scale (off the root note), as Imaj7 (IVmaj7 can also be created).

Now consider the m7 chord: m7 = 1,b3,5,b7
m7 can be created off the 2,3,and 6 respectively to create ii7, iii7, and vi7. You DON'T; however, create a minor chord off the root note of the major scale.

The false teaching, promulgated by those who don't understand the processes that lead to the end result or the nomenclature conventions, is that to create the m7 chord (1,b3,5,b7) you would take the chord off the root note in the major scale (maj7 = 1,3,5,7), and then alter it to create the m7 chord (by flatting the 3 and the 7). This is wrong, and shows a lack of understanding of harmonization. The reality is that we use the major scale as a reference with which we analyze various structures ( and that statement oversimplifies much musical history).

Viewing constructs (chords or scales) as pure sounds means that we needn't treat everything as having to be in a context simply because we can create an arbitrary context for it. (Most things happen in context, some do not).

As an example of a pure sound (vs. a synthetic alteration):
1.) Randomly place your fingers on the fretboard in an unknown shape.
2.) name that chord.
3.) Realize that you randomly created a chord, it was not from some scale, it was not created from altering another chord. It was arbitrary, and any name it has does not tell you how or why that chord came into existence.

As korzybsky would say,
"the map is not the territory" or,
"the menu is not the meal".

The chord's name (or intervals) don't tell you anything more than certain notes are to be played at a particular time (approximately). We can make educated guesses with chords and find a context, but we should not aasume that the context is correct, it is the only context, or was even intended.

And last for the jazz fans out there...

THE Alt chord
e.g. Galt , G7alt, etc.

Seen in jazz heads, the dominant alt chord is the dominant ninth chord with both an altered fifth, and an altered ninth.
ALT = 1,3,b5 and/or#5, b7, b9 and/or #9

The alt chord can have both fifths (b5/#5) and both ninths (b9/#9), or any combination that includes at least one altered fifth, and one altered ninth.

So the alt chord could be:
alt = 1,3,b5,b7,b9
alt = 1,3,b5,b7,#9
alt = 1,3,b5,b7,b9,#9
alt = 1,3,b5,#5,b7,b9
alt = 1,3,b5,#5,b7,#9
alt = 1,3,b5,#5,b7,b9,#9
alt = 1,3,#5,b7,b9
alt = 1,3,#5,b7,#9
alt = 1,3,#5,b7,b9,#9

the notation gives you some freedom to choose how to express the alt chord.

It might be noted that the alt chord in all of it's variations can be pulled out of the altered dominant scale (also called the superlocrian scale, or 7th mode of the melodic minor scale)
Alt dom scale = 1/2-W-1/2-W-W-W-W
Alt dom scale = 1,b2,#2(b3),3,b5,#5(b6),b7

It might also be noted that the alt chord in some of it's variations can be pulled out of the symmetric diminished scale (also called the diminished scale, or 1/2-W)
Sym dim scale = 1/2-W-1/2-W-1/2-W-1/2-W
Sym dim scale = 1,b2,#2(b3),3,b5(#4),5,6,b7
and one could use that scale as a starting ground for soloing over the alt chord (it is missing the #5, and one should avoid the 5).

Another half-option is the wholetone scale (1,2,3,b5,#5,b7) which is missing the 9's.

Next lesson is on the min/maj7 chord.

Christopher Roberts

How do I change all those numbers to letters (for notes, chords, etc.)? Here's a transposition chart

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Last updated August 22, 2002
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