Music Theory

Topic overviews

The links below give a very brief overview of each topic, including an example in one musical key.

Note name, Chromatic scale, Major scale, Natural minor scale, Harmonic minor scale, Melodic minor scale, Relative minor, Circle of fifths, Key signature, Blues scale, Pentatonic scale, Note interval, Mode, Triad chord, Sixth chord, Seventh chord, Scale chord, Mode chord.

However, most of the site content can be found below.

Topics by key

1. Site introduction

Most music theory sites describe each topic (scales, modes etc.) then provide simple examples in one key.

basicmusictheory.com works the other way around - it describes music theory within the context of a specific key.

So for example, to learn how any major scale is constructed, you can click on any of the major scale links above - they all contain the same core content describing how the scale is constructed.

But to learn how the major scale is constructed for specific key, click specifically on that link eg. C major scale, which will show the scale construction, and note names specifically for that key.

To get started, the topic introduction sections below highlight the simplest and most complex keys to learn.

Nearly all the pages on this site start with the diagram shown above, from B to C.

The second note always has a orange line underneath it, indicating middle C / midi note 60, on the piano.

When middle C is used in bass and treble clef diagrams, it is also shown with a orange bar through the note.

This convention is unique to this site, and has been done to make clear which notes the audio (midi/mp3) files contain, in relation to the piano and clef diagrams.

This blank piano diagram is the starting step from which all topics begin.. notes, scales, modes, chords, everything.

Each topic has a number of steps, each of which adds a layer of construction detail onto that diagram until the topic is complete, and the final note names are shown.

Examples of completed diagrams for each topic are shown in the topic introduction sections below.

2. Note name

The example on the piano diagram below shows the Eb note highlighted.

Black note names

From the piano diagram above, you can see that all black notes have two possible names - a sharp and a flat name.

The choice as to whether a black note takes the sharp or flat name depends on the scale or chord being constructed that uses that note.

For example, the black key highlighted above is called note Eb when used in the Db major scale but is called D# when used in the B major scale scale.

But crucially, these two notes sound the same - it is just the note names that are different.

In music theory, it is said that these two note names are enharmonic to each other.

Natural white note names

The white notes are shown with a single note name from A to G, with no sharp or flat signs. They are called natural when they do not have to be sharpened, or flattened when constructing a scale or chord.

Sharp and flat white note names

Be aware that white notes can also have sharp or flat names.

For example, white note C, when flattened, becomes note Cb, which has the same pitch, and is actually note B that is being played on the piano.

Again, depending on the scale being constructed in a particular key, either name could be used.

For example, note name B is used when constructing the D major scale, but this pitch / sound is called Cb when used to construct the Gb major scale.

In the same way, when note E is sharpened for use in a scale, it is called E# which occupies the F white note position.

Or when note F is flattened, it is called Fb which occupies the E white note position.

Finally, when note B is sharpened, it is called B# which occupies the C white note position.

Double accidentals

When constructing scales, it is theoretically possible for a note name to have a double sharp, that is adjusted by 2 half-tones / semitones / piano keys up or down.

For example, the D# major scale scale contains 2 double-sharps, and the A# major scale contains 3.

However, both of the scales are rarely used and are difficult to work with, so the scales Eb major scale and Bb major scale are often used in their place, which contain the same note pitches as the other scales. ie. the scales are enharmonic.

Given a pair of enharmonic scales with identical pitches, it makes sense to use the scale that has the fewest sharps and flats.

Triple accidentals

When constructing chords, it is even possible for a note name to have a triple accidental, that are adjusted by 3 half-tones / semitones / piano keys up or down.

For example, the B# augmented chord contains a triple sharp, but again, this chord is difficult to work with, so the enharmonic equivalent - C augmented chord is often used instead.

3. Chromatic scale

1 octave - 12 notes

Chromatic scales contain 12 notes, and include every note including the starting tonic note highlighted as the first blue note below. All white and black keys are used.

The 13th note (also in blue) is the same note name as the tonic note, but is 1 octave higher, and has twice the frequency of note 1.

So note 1 - E-flat above middle C has a frequency of 329.63 Hz, and note 13 is (2 x 329.63) = 659.26 Hz.

The next E-flat (which would be shown as note 26) has twice the frequency again - 1318.51, and so on.

The Eb chromatic scale shows the E-flat chromatic scale above.

Chromatic scale naming in the context of a key signature

If chromatic scale notes are being used and identified within the context of a scale with a key signature (eg. major scale, or any minor scale), then the key signature will be the guide as to whether to use sharps or flats for the chromatic scale.

For example, if a sharp-based key signature is used, eg. G major key signature, and we want to use the chromatic scale to identify notes outside that scale, sharps would be used for those chromatic scale notes.

The same principle applies to flat-based key signatures, eg. Eb major key signature, where flat note names would be used.

Chromatic scales without a key signature

For both C major key signature and A natural minor key signature, there are no sharp or flat notes, so since there is no key signature, we have no clue as to whether to use sharp or flat names to identify any non-natural notes.

Although there seem to be no generally agreed rules on how to handle this, one common music theory convention is to use sharps when ascending the scale ie. when playing the notes from lowest to the highest pitch, then use flats when descending.

4. Major scale

Structure

Major scales contain 7 notes, and all use the  W-W-H-W-W-W-H  tone / half-tone pattern to identify the note positions.

The first note in the diagram below (*) is the tonic note, from which the counting pattern begins.

To count up a Whole tone, count up by two physical piano keys, either white or black.

To count up a Half-tone (semitone), count up from the last note up by one physical piano key, either white or black.

So in the example below, we are interested in the major scale in the key of E-flat.

No matter which key name (or color - black / white) a major scale starts on, the same pattern above is used.

The 8th and final note in the diagram is the octave note, named the same as the tonic note, and is the note where the scale and tone / half-tone pattern rule starts repeating all the way up the piano keyboard.

To understand the frequency relationship between a tonic and its octave note, have a look at the Chromatic scale overview.

Examples

Below is an example using the Eb major scale.

To learn about major scales, start with the C major scale, which has no sharps or flats, only white / natural notes, just to see how the note positions are identified.

Then maybe have a look at the Eb major scale as shown below, which contains 3 flats.

There might appear to be 4 flats above, but the 4th flat is just the octave of the tonic note, where the pattern starts repeating, so it doesn't count.

More complex still is the Cb major scale which has all 7 notes flattened, and the C# major scale which has all 7 notes sharpened.

The All major scales page contains piano diagrams and key signatures for all major scales.

5. Natural minor scale

Structure

The terms minor scale and natural minor scale mean the same thing in music theory.

Natural minor scales contain 7 notes, and all use the  W-H-W-W-H-W-W  tone / half-tone pattern to identify the note positions.

The first note in the diagram below (*) is the tonic note, from which the counting pattern begins.

To count up a Whole tone, count up by two physical piano keys, either white or black.

To count up a Half-tone (semitone), count up from the last note up by one physical piano key, either white or black.

So in the example below, we are interested in the minor scale in the key of E-flat.

No matter which key name (or color - black / white) a major scale starts on, the same pattern above is used.

The 8th and final note in the diagram is the octave note, named the same as the tonic note, and is the note where the scale and tone / half-tone pattern rule starts repeating all the way up the piano keyboard.

To understand the frequency relationship between a tonic and its octave note, have a look at the Chromatic scale overview.

Examples

Below is an example using the Eb natural minor scale.

To learn about minor scales, start with the A natural minor scale, which has no sharps or flats, only white / natural notes.

In fact, it contains the same notes as the C major scale, but a different note is used as the starting (tonic) note in each case.

Then maybe have a look at the Eb natural minor scale as shown above, which contains 6 flats.

More complex still is the A# natural minor scale which has all 7 notes sharpened.

The All minor scales page contains piano diagrams and key signatures for all (natural) minor scales.

To understand the differences between the major and minor scale for a given key, have a look at any natural minor link on this page, which show the note differences for the specific key you are interested in.

To see the relationships between all major and minor scales on a diagram, have a look at the Circle of fifths diagram.

6. Harmonic minor scale

Structure

A harmonic minor scale in a given key is similar to the Natural minor scale in the same key, except that the 7th note is raised by 1 half-tone / semitone to arrive at the harmonic minor scale.

The harmonic minor scale uses the  W-H-W-W-H-W½-H  note counting pattern to identify the scale note positions.

The first note in the diagram below (*) is the tonic note, from which the counting pattern begins.

To count up a Whole tone, count up by two physical piano keys, either white or black.

To count up a Half-tone (semitone), count up from the last note up by one physical piano key, either white or black.

To count up a W½ tone (whole-tone and a half), count up from the last note by 3 half-tones / semitones - shown as 3 in the piano diagram below.

So in the example below, we are interested in the harmonic minor scale in the key of E-flat.

No matter which key name (or color - black / white) a major scale starts on, the same pattern above is used.

The 8th and final note in the diagram is the octave note, named the same as the tonic note, and is the note where the scale and tone / half-tone pattern rule starts repeating all the way up the piano keyboard.

To understand the frequency relationship between a tonic and its octave note, have a look at the Chromatic scale overview.

Examples

The example below, Eb harmonic minor scale, uses the key of E-flat.

The All harmonic minor scales page contains piano diagrams and key signatures for all harmonic minor scales.

7. Melodic minor scale

Structure

A melodic minor scale in a given key is similar to the Natural minor scale in the same key, except that both the 6th and 7th notes are raised by 1 half-tone / semitone to arrive at the melodic minor scale.

The melodic minor scale uses the  W-H-W-W-W-W-H  note counting pattern to identify the scale note positions.

The first note in the diagram below (*) is the tonic note, from which the counting pattern begins.

To count up a Whole tone, count up by two physical piano keys, either white or black.

To count up a Half-tone (semitone), count up from the last note up by one physical piano key, either white or black.

So in the example below, we are interested in the melodic minor scale in the key of E-flat.

The 8th and final note in the diagram is the octave note, named the same as the tonic note, and is the note where the scale and tone / half-tone pattern rule starts repeating all the way up the piano keyboard.

Be aware that when descending this scale, sometimes the notes of the Eb natural minor scale are played instead.

To understand the frequency relationship between a tonic and its octave note, have a look at the Chromatic scale overview.

Examples

The example below, Eb melodic minor scale, uses the key of E-flat.

The All melodic minor scales page contains piano diagrams and key signatures for all melodic minor scales.

8. Relative minor

The relative minor of a major scale in a given key is the (natural) minor scale that contains the same note names as that major scale.

Every major scale key has a relative minor.

Given a major scale in a given key, the key / tonic of its relative minor is the 6th note of the major scale.

Using E-flat as an example, the 6th note of the Eb major scale is note C, so the relative minor scale is C natural minor scale.

The key / tonic of a relative major is the 3rd note of a given minor scale.

From the minor scale diagram above, the 3rd note is Eb, so the relative major scale is Eb major scale.

To see the relative minors of all 12 common major and minor scales on a diagram, have a look at the Circle of fifths.

9. Circle of fifths

The Circle of fifths diagram below is the heart of basic music theory, and is possibly the most important section on this site to read after understanding how major and (natural minor) scales are constructed.

Having learned how to draw it from memory using a few simple memorable phrases, you will automatically know how many sharps and flats are in all popular scales without working them out by hand.

You will also know all the relative major / minor scales, which scales contain identical note pitches, but have different note names, and which scales sound most alike and work well together.

The Circle of 5ths sections seem to be long, and there appears to be a lot of material to get through, but there is a lot of repetition once you see the patterns, then you will fly through it.

Suggest printing out or saving the above diagram on your desktop for reference before you start.

Get started now with Circle of 5ths first section - 1. Introduction.

10. Key signature

Purpose

When a piece of music is written in a given key, the sharp and flat symbols of that key can be written at the beginning of the staff to save having to repeatedly write those accidental symbols before every note on the staff.

Missing key signatures

If a key signature would not be useful in simplifying the musical arrangement, it need not be used at all, in which case each sharp or flat symbol is shown before each note on the staff.

The other situations where the key signature appears to be missing is for the C major key signature and A natural minor key signature, neither of which contain any sharp or flat notes, so no symbols are shown after treble or bass clef.

Key signature note positions

The key signature is set of sharps or flats (never mixed) shown after the treble or bass clef on the musical staff.

Below is the Cb major key signature which has 7 flat notes, on the treble then bass clef.

This example is used because it shows the key signature positions of all possible notes - ie.all scale notes (from A to G) have been flattened.

The exact order and position of the key signature symbols after the clef symbol varies according to whether it is a sharp or flat-based key signature.

Flat key signatures, like the one above, use the Battle Ends And Down Goes Charles Father pattern.

For an example of this, have a look at the Cb major key signature, which describes this phrase's origin ( the circle of fourths ) in more detail.

Sharp-based key signatures

Sharp key signatures use the Father Charles Goes Down And Ends Battle pattern.

For an example of this, have a look at the C# major key signature, which describes this phrase's, origin (the circle of fifths ) in more detail.

Identifying middle C on both clefs

Bass clef notes are usually used to show notes lower in pitch / sound than treble clef notes.

On this site (only), a convention is used for all key signatures where middle C is shown with an orange line through it (you can see this on the piano diagrams too).

So on the clefs above, you can see that middle C is the first note of the treble clef and the last note of the bass clef.

Of course, it is also possible for the treble clef to shown notes lower than middle C, and for the bass clef to shown notes higher than middle C, so the diagrams above are just to demonstrate the meeting point of both clefs.

Treble versus bass clef note positions

An interesting thing about the diagrams above is that the symbols are the same, except the bass clef symbols are shifted down the staff lines by one two positions (1 line + 1 space).

This means that any given note, eg. C does not sit on the same line/space position on each clef.

On the bass clef, for example, note C occupies the same space as note A does on the treble clef.

Major and relative minor scales

All of the rules above apply equally to major and natural minor key signatures.

And since each major scale has a relative minor scale (and vice versa), which contains the same notes, it follows that they both have the same key signature.

For example, the A major key signature has 3 sharps, as does its relative minor, the F# natural minor key signature, and so their key signatures are identical.

This relationship is outlined in the Relative minor topic overview, and explained in detail for each key, eg. A relative minor.

Harmonic minor and melodic minor scales

For major and (natural) minor scales, the key signature directly reflects the exact notes in the scale.

However, harmonic minor and melodic minor scales, borrow the key signature of the natural minor key signature (in the same key), and then show the note differences as accidentals before each note difference on the staff.

For example, both the Eb harmonic minor key signature and Eb melodic minor key signature borrow the Eb natural minor key signature.

11. Blues scale

There are 2 common ways to construct the blues scale - either using the major or the minor pentatonic scale of a key.

Blues construction from a major scale

The blues scale is made from the 1st, flattened 3rd, 4th, flattened 5th, 5th and flattened 7th notes from the major scale for a given key.

The music theory term flattened means to lower the note by half-tone / semitone / piano key.

The flattened 5th note of the major scale is the blue note that gives the scale its unique character.

The 7th and final note in the diagram is the octave note, named the same as the tonic note, and is the note where the scale starts repeating all the way up the piano keyboard.

For example, in the key of E-flat, below is the Eb blues scale.

Blues construction from a minor pentatonic scale

To construct the blues scale from the minor pentatonic scale, take the 4th note of that scale, flatten it, and insert it before the 4th note position of the same scale. This 4th note is the blue note.

Yet another (more complex) way to identify the blue note is to take the Diminished 5th note interval based the tonic note, but it is usually easier to work it out from scales rather than intervals.

Blues construction examples - Major Vs Minor

The blues scale links at the top of this page are all keys from the Circle of fifths diagram.

Some of these keys are shown on the circle of 5ths diagram as being major, minor or both.

To see the blues scale construction using a major scale, choose a link above that is shown in Red on the circle of 5ths diagram, eg. Cb blues scale

To see the blues scale construction using a minor scale, choose a link above that is shown in Green on the circle of 5ths diagram, eg. A# blues scale

Some keys are both major and minor, in which case both major and minor constructions are shown, for example - D blues scale.

12. Pentatonic scale

The minor pentatonic scale is made from the 1st, 3rd, 4th, 5th and 7th notes from the minor scale for a given key.

The major pentatonic scale is made from the 1st, 2nd, 3rd, 5th and 6th notes from the major scale for a given key.

The 6th and final note in the diagram is the octave note, named the same as the tonic note, and is the note where the scale starts repeating all the way up the piano keyboard.

Below is an example of a pentatonic major scale - the Eb major pentatonic scale.

13. Note interval

A note interval describes the relationship, and the number of half-tones / semitones / piano keys between two different notes.

Note intervals are commonly used in music theory to identify the individual note names of chords.

Note interval components

A note interval is made up of 3 components.

The first component is a note name eg, Eb, which is the note above which the interval is measured, ie. we want to measure an interval starting from note Eb

The second component is the interval number, which is a note number of the major scale whose tonic is the note name. ie. we want to measure from the starting note up to eg. the 3rd note of the major scale.

The third component is an interval quality, which might be a pitch adjustment, up or down, to the note at the interval number.

Note interval qualities

Note interval qualities are called diminished, minor, major, perfect and augmented. eg. we want to measure from the starting note up to eg. the 3rd note of the major scale, with a diminished quality.

The piano diagram below shows all the note interval qualities of the Eb-3rd interval.

Note interval table

Below is a table showing all note intervals that can be measured starting from any note name on the piano.

Column ordering

Each semitone number(first column) is used twice, which means that it is never possible to calculate the name of an interval by counting only the number of half-tones / semitones. The interval number (last column) is needed too.

For example, the interval distance of 5 half-tones / semitones between two notes could be called a perfect 4th or an augmented 3rd.

Using our E-flat scale to demonstrate this, the Eb-perf-4th (A-flat) and Eb-aug-3rd (G-sharp) intervals have the same distance in half-tones / semitones.

This is not surprising, since A-flat and G-sharp are different names for the same note on a piano keyboard.

Major and perfect interval groupings

When it comes to identifying the name of a note for an interval, the name of the perfect or major interval is used as a starting point from which the other intervals grouped around it are named.

Remember the 1st, 4th, 5th and 8th notes of a major scale are always perfect, and the others - 2nd, 3rd, 6th and 7th are aways major.

So you will never see a perfect 3rd, or a major 5th interval.

Interval spelling / formula

In music theory, note intervals can also be expressed using using a spelling or formula, which mean the same thing. You may have seen a chord expressed as 1 b3 5, for example.

Each interval has a spelling that represents its position relative to the major or perfect interval of the same interval number. Flat signs (b) are used for intervals lower, and sharp (#) for intervals higher.

The final column shows all spellings, and as you can see it is even possible for an interval to be two notes lower (bb) than a major interval

Interval quality names differ by group

Be aware that the interval qualities around major qualities are different to those around perfect qualities.

Using the above example, a perfect interval eg. Eb-perf-4th has a diminished quality 1 half-tone / semitone down from it.

Compare this to, a major interval eg. Eb-aug-3rd, which has a diminished quality 2 half-tones / semitones down from it.

When starting out exploring intervals using the links above, always be aware to choose a perfect and a major interval to compare the the quality name differences between them.

However, to start off, suggest comparing the intervals around two different perfect intervals eg. Eb-perf-4th and Eb-perf-5th, while keeping the above table to hand as a reference.

Then compare the intervals around two different major intervals eg. Eb-maj-3rd and Eb-maj-6th.

Finally, compare a major and perfect interval eg. Eb-aug-3rd and Eb-perf-4th, to demonstrate that two different quality names can occupy the same piano key ie. from the table above, both P4 and A3 are 5 semitones from the base note - E-Flat.

How to invert an interval

An inverted interval is just an interval that is turned upside down.

For example, one of the intervals we identified about was an augmented 3rd above Eb, which is note G#.

In contrast, an inverted interval specifies the distance from G# to Eb - ie. note Eb is above note G#.

A set of fixed rules exist to help us calculate the new quality name and interval number:

Note interval quality inversion rules

> A major interval always inverts to a minor interval.

> A minor interval always inverts to a major interval.

> A perfect interval always inverts to a perfect interval - no change.

> A diminished interval always inverts to a augmented interval.

> An augmented interval always inverts to a diminished interval.

So in our example - an augmented 3rd above Eb, the original interval is augmented, which inverts to diminished.

Note interval number inversion rules

Simply subtract the original interval number from 9, resulting in the inverted interval number.

For our example - an augmented 3rd above E-flat, we subtract 3 from 9, leaving the inverted interval number 6 - ie. a 6th above G#.

Putting it all together, the original interval - Eb-aug-3rd inverts to G#-dim-6th, which means that G#-dim-6th will take you to note Eb, the note above which we calculated our original interval.

14. Mode

Modes are similar to scales in that each mode is a set of 7 notes, with the letters C to B being used once and once only in each mode.

Below is a list of all mode names and note names in each.

In their simplest / untransposed form, modes do not contain any sharp or flat notes.

This means that they do not contain any black notes - only the white(natural) note names of the piano are used.

This also means that since the C major scale contains no sharp or flat notes, all modes in their untransposed form are directly related to the C major scale, and can be expressed in terms of this scale.

For example, we could say that the ionian mode is the first mode (and is identical to) the C major scale.

Or we could say that the phrygian mode is the 3rd mode (ie. starts on the 3rd note, and uses all notes) of the C major scale.

The 6th mode of the C Major scale (aeolian) is interesting, since it is also identical to the A natural minor scale.

This is not surprising, since the tonic of C Major relative minor - C relative minor is calculated using the 6th note of the major scale.

Below is an example of the phrygian mode.

However, it is possible to transpose a mode to a different key, which is to take the tone-semitone pattern for a specific mode that was used to skip the black notes, and apply that pattern starting on any other note on the piano keyboard.

Once transposed, it is possible that the transposed mode might contain sharp and flat notes.

The newly transposed mode name will have the key name in front of the mode eg. G phrygian mode

For untransposed modes as shown in the table above, it is not necessary to name the key - if you use the term phrygian it is understood that this mode starts on note E.

15. Triad chord

Triad chord definition and construction

Triad chords contain 3 notes played together, or overlapping.

Triad qualities table

There are 4 different main qualities of triad chords - major, minor, augmented, and diminished.

Each chord differs by the 2nd and 3rd notes as shown below.

An augmented chord is usually shown with a plus symbol:    ⁺

A diminished chord is usually shown with a circle symbol:    ^o

Each quality has a different musical flavour, but they all share the same starting note, or root, for a given key.

For example, the Eb major scale has note Eb as the tonic / starting Note, so Eb is the root note of all triad chord qualities in this key.

Triads qualities using the 3rd scale note

The 2nd and 3rd notes of all triad chord qualities above are based on variations of the 3rd and 5th notes of the same major scale (eg. notes G and Bb for E-flat). For example:

The Eb major chord uses these 3rd / 5th note names exactly as they are, with no adjustments.

The Eb minor chord uses the 3rd that is 1 half-tone / semitone / piano key lower than the major quality, so the 3rd note is Gb instead.

The Eb augmented chord uses a 5th that is 1 half-tone / semitone/ piano key higher than the major quality, so the 5th note is B instead.

The Eb diminished chord has both a 3rd and 5th that are 1 half-tone / semitone/ piano key lower than the major quality, so those notes are Gb, Bbb respectively.

To understand why this note is called Bbb, but it is occupying the note A position on the piano diagram below, have a look at the Eb diminished chord page, which explains how note intervals are used to name the individual notes.

The note intervals for the Eb diminished chord are Eb-min-3rd and Eb-dim-5th, whose names are abbreviated on the piano below as m3 and d5.

Suspended triad chords

A suspended chord is known in music theory as an altered chord because it takes one of the above chord qualities and modifies it in some way.

Unlike all of the triads above, suspended triads do not use the 3rd scale note, so it is not possible to classify them as either major or minor. Instead they use either 2nd or 4th note.

So the Eb suspended 4th chord is identical to the Eb major chord except the 2nd note (a major 3rd) is replaced - suspended, in favor a perfect 4th - note Bb.

The Eb suspended 2nd chord is identical to the Eb major chord except the 2nd note (a major 3rd) is replaced - suspended, in favor a major 2nd - note F.

Triad chord inversions

The order of the notes in a triad chord as described above have the root note Eb as the lowest / first note of the chord. This is triad in root position.

By moving the root note up one octave to the end of the chord, the 1st inversion of that triad is created, which now has Gb as the first note in the example above.

By moving the first note of the 1st inversion to the end of that chord, the 2nd inversion is created, which has Bbb as the first note.

Inversions do not change the notes in a triad - they simply change the note order.

16. Sixth chord

6th chord definition and construction

Sixth chords contain 4 notes played together, or overlapping.

Like triad chords shown in Triad chord, sixth chords have different qualities, with the most common shown in the last column of the table below.

Sixth chords are built on triad chord qualities, but with an extra note, whose name is based on the 6th note of the major scale.

The piano diagram above shows the Eb major 6th chord which is the same as the Eb major chord, except that it has one extra note, defined using the Eb-maj-6th note interval as shown in the second row of the table above.

6th chord inversions

6th chord inversions work in the same way as triad inversions explained in Triad chord, except since there is one more note in the chord, there is one extra inversion that can be done.

Using the 6th chord above, the root position 6th chord has Eb as the first note.

For the 1st inversion, this note is moved to the end leaving note G as the first note.

For the 2nd inversion, G from the 1st inversion is moved to the end leaving note Bb as the first note.

For the 3rd inversion, Bb from the 2nd inversion is moved to the end leaving note C as the first note.

17. Seventh chord

7th chord definition and construction

Seventh chords contain 4 notes played together, or overlapping.

Like triad chords shown in Triad chord, seventh chords have different qualities as shown in the last column of the table below.

Seventh chords are built on triad chord qualities, but with an extra note, whose name is based on the 7th note of the major scale.

> An augmented chord is usually shown with a plus symbol:   ⁺

>A diminished chord is usually shown with a circle symbol without a line through it:    ^o

>A half-diminished chord is usually shown with a circle symbol with a line through it:    ^ø

The piano diagram above shows the Eb dim 7 chord which is the same as the triad chord shown in the triad section above, except that it has one extra note, defined using the Eb-dim-7th note interval as shown in the first row of the table above.

7th chord inversions

7th chord inversions work in the same way as triad inversions explained in Triad chord, except since there is one more note in the chord, there is one extra inversion that can be done.

Using the 7th chord above, the root position 7th chord has Eb as the first note.

For the 1st inversion, this note is moved to the end leaving note Gb as the first note.

For the 2nd inversion, Gb from the 1st inversion is moved to the end leaving note Bbb as the first note.

For the 3rd inversion, Bbb from the 2nd inversion is moved to the end leaving note Dbb as the first note.

18. Scale chord

Purpose

Given a major scale or minor scale in any key, it is possible to work out a set of triad (3 note) or 7th (4 note) chords that harmonize with that scale.

These chords sound good played underneath the notes of a given scale because they are made up only from notes in that scale.

In fact, for each note of the scale there is a corresponding triad and seventh chord that whose root ie. starting note, is that scale note.

Example

As an example, let's use the Eb major scale shown below.

Chords based on 1st scale note - the tonic

Triad chords are built using the 1st, 3rd and 5th notes of a scale so the first triad is constructed using notes Eb, G and Bb.

Seventh chords are built from triads, with one extra note - the 7th scale note.

So the 7th chord has notes Eb, G Bb, and D - scale notes 1, 3, 5, and 7.

Chords based on 2nd scale note

The 2nd chord's root - ie starting note, is the 2nd scale note - F, together with the 4th and 6th notes - Ab and C. ie. you count the 3rd and 5th relative to the chord root.

The 7th chord has the same notes, plus one extra note - the 8th scale note, which is the same note as the original tonic of the scale.

So the 7th chord has notes F, Ab, C, and Eb - scale notes 2, 4, 6, and 8.

Chords based on 3rd+ scale note

This process is repeated for the remaining chords - just move up the next scale note, make it the root, and calculate the 3rd, 5th and 7th scale notes above it.

Although at this point it appears that we have hit the the 'end' of the scale (note 8), the scale just repeats itself, so note 9 is the same as note 2 - note F, and so on.

So the 3rd chord's root is G, and the remaining triad notes are a 3rd above that - Bb, and D.

The 7th chord based on the 3rd note therefore has the above note plus note F - scale notes 3, 5, 7, 9 (2).

Chord Qualities

That was quite easy - all we did was skip each note of the scale to identify the next chord note.

The trickier bit is to work out the name of the chord we have created in each case.

Based on the notes we have in each chord, should the chord quality be major, minor, augmented, diminished, or something else ?

That depends (on a chord by chord basis) on the Note interval relationship between the root and the other chord notes.

More on these interval relationships are at Triad chord and Seventh chord, and the links at the top of this page describe, for a given key, these chords in detail - the notes to use, and the chord quality name.

The remainder of the text below is a summary of all of that information laid out in a couple of tables - first for triads, then for seventh chords.

Scales - triad chord qualities table

The chart below shows the triad chord qualities of the Triad chord for each of the 7 notes in the scale.

Table rows

The Note no. row is the note number of the scale which we want to be the root (or starting note) of the triad chord.

The Scale degree row is a name given to that note number that represents its purpose in the scale.

The remaining rows show the triad chord quality names for each of the scales.

For example, for harmonic minor scale 3rd column shown below, we are saying that the name of the triad chord name for the 3rd scale degree (mediant) of the harmonic minor scale is always an augmented triad chord.

Using E-flat as the example key again, we know that the 3rd note of the Eb harmonic minor scale is note Gb. So the name of the triad chord we want is Gb augmented chord.

These chart rules always hold no matter which key the scale is in.

Symbols used

To understand the chord symbols ( ^{o +} ) used in this table have a look at Triad chord.

The roman numerals (i, ii, ii, iv, v, vi, vii) are used to identify the 7 chords in a scale. For example, it is common to see something like chord IV of the major scale meaning the 4th chord of the major scale.

The roman numeral will be in upper case if the chord is a major chord ie. has a major 3rd interval, and in lower case if the chord is minor chord ie. has a minor 3rd interval.

Scales - 7th chord qualities table

Below is a similar chart for 7th chords - exactly the same rules apply as for triad chords, except that the chord qualities are taken from the Seventh chord chart instead.

To understand the chord symbols ( ^{o + ø} ) used in this table have a look at Seventh chord.

The use of roman numerals for 7th chords works in the same way as triads described above - upper case for major 3rd chords, lower case for minor 3rd chords. The ⁷ is shown after each chord name to indicate it is a 7th chord.

19. Mode chord

Purpose

Given any mode in any key, it is possible to work out a set of triad (3 note) or 7th (4 note) chords that harmonize with that mode.

These chords sound good played underneath the notes of a given mode because they are made up only from notes in that mode.

In fact, for each note of the mode there is a corresponding triad and seventh chord that whose root ie. starting note, is that mode note.

Example

As an example, let's use the phrygian mode shown below.

Chords based on 1st mode note - the tonic

Triad chords are built using the 1st, 3rd and 5th notes of a mode so the first triad is constructed using notes E, G and B.

Seventh chords are built from triads, with one extra note - the 7th mode note.

So the 7th chord has notes E, G B, and D - mode notes 1, 3, 5, and 7.

Chords based on 2nd mode note

The 2nd chord's root - ie starting note, is the 2nd mode note - F, together with the 4th and 6th notes - A and C. ie. you count the 3rd and 5th relative to the chord root.

The 7th chord has the same notes, plus one extra note - the 8th mode note, which is the same note as the original tonic of the mode.

So the 7th chord has notes F, A, C, and E - mode notes 2, 4, 6, and 8.

Chords based on 3rd+ mode note

This process is repeated for the remaining chords - just move up the next mode note, make it the root, and calculate the 3rd, 5th and 7th mode notes above it.

Although at this point it appears that we have hit the the 'end' of the mode (note 8), the mode just repeats itself, so note 9 is the same as note 2 - note F, and so on.

So the 3rd chord's root is G, and the remaining triad notes are a 3rd above that - B, and D.

The 7th chord based on the 3rd note therefore has the above note plus note F - mode notes 3, 5, 7, 9 (2).

Chord Qualities

That was quite easy - all we did was skip each note of the mode to identify the next chord note.

The trickier bit is to work out the name of the chord we have created in each case.

Based on the notes we have in each chord, should the chord quality be major, minor, augmented, diminished, or something else ?

That depends (on a chord by chord basis) on the Note interval relationship between the root and the other chord notes.

More on these interval relationships are at Triad chord and Seventh chord, and the links at the top of this page describe, for a given key, these chords in detail - the notes to use, and the chord quality name.

The remainder of the text below is a summary of all of that information laid out in a couple of tables - first for triads, then for seventh chords.

Modes - triad chord qualities table

The chart below shows the triad chord qualities of the Triad chord for each of the 7 notes in the mode.

Table rows

The Note no. row is the note number of the mode which we want to be the root (or starting note) of the triad chord.

The Scale degree row is a name given to that note number that represents its purpose in the mode.

The remaining rows show the triad chord quality names for each of the modes.

For example, for the bold table cell shown below, we are saying that the name of the triad chord name for the 2nd scale degree (supertonic) of the lydian mode is always a major triad chord.

Using phyrgian as the example mode again, we know that the 2nd note of this mode is F, so the name of the triad chord we want is the F major chord.

These chart rules always hold no matter which key the mode is in.

Symbols used

To understand the chord symbols ( ^{o +} ) used in this table have a look at Triad chord.

The roman numerals (i, ii, ii, iv, v, vi, vii) are used to identify the 7 chords in a mode. For example, it is common to see something like chord IV of the lydian mode meaning the 4th chord of the lydian mode.

The roman numeral will be in upper case if the chord is a major chord ie. has a major 3rd interval, and in lower case if the chord is minor chord ie. has a minor 3rd interval.

Modes - 7th chord qualities table

Below is a similar chart for 7th chords - exactly the same rules apply as for triad chords, except that the chord qualities are taken from the Seventh chord chart instead.

To understand the chord symbols ( ^{o + ø} ) used in this table have a look at Seventh chord.

The use of roman numerals for 7th chords works in the same way as triads described above - upper case for major 3rd chords, lower case for minor 3rd chords.