Seventh Chords

Go beyond basic triads and start using four-note chord structures. We'll talk about standard structures, scale, and modes. Then we'll progress into the world of double-flat sevenths and tri-tones.

Seven Chords or Seventh Chords?

When I first started learning music, I noticed these chords with the number seven in their name. I had no idea of what they were and just played power chords or fifths to get by. I can remember someone at a music shop asking me if I knew my seventh chords. I understood it as “seven chords” and said I did. What I was agreeing to was that I could play the seven chords of the major scale. Oh, how wrong I was.

It wasn’t until years later that I started to play Major 7, Minor 7, and Dominant 7 chords correctly and I still didn’t fully understand where the unique sound of those chords came from. Then came the dreaded Minor 7 b5 and scales with double flatten seventh degrees. I was a fish out of water, but soon I was able to breathe again and slowly learned out to use each of these four note chords to my advantage.

Where to Start?

A good place to begin is with the idea that chords and scales are the same thing. If you play several notes of a scale at once, then you are playing a chord. That chord is part of a scale and can be thought of as a structure that is embedded in a scale.

Let’s take a quick look at the first octave of the chromatic scale starting on C.

The natural degrees of 1 through 7 have the notes C, D, E, F, G, A, and B. The altered degrees of b2, b3, b5, b6, and b7 are the notes Db, Eb, Gb, Ab, and Bb. The 1st degree at the right side of the above diagram is labeled this way because it is also the note C, which starts the next octave.

When we talk about the seventh degree of a scale, we can be one of three notes. The Major 7 is the natural seventh degree, which is B in this example. The Flat 7 or Dominant 7 is Bb. The Double Flat 7 or Fully Diminished 7 is A.

The reason for these names and notes has to do with where they come from in their corresponding scale. Let’s look at the scales that match these seventh degrees.

The Major Seventh Degree

When we use scales or modes like Ionian, Lydian, or Melodic Minor we have access to the Major Seventh. Below are diagrams for these three scales.

Starting with Ionian we have only the natural interval degrees, while Lydian has a sharpened fourth degree and Melodic Minor has a flattened third degree. If you are not familiar with Melodic Minor, then it is likely due to it not being part of the Major Scale. Melodic Minor is the first mode of a different set of scales but is a good example for the Major 7 degree.

When we build natural chords that use the any of our sevenths we start off with a triad or three-note chord. These chords are either major, minor, diminished, or augmented which is notated with a +. Both Ionian and Lydian have major chords in them since they both have the degrees 1, 3, and 5. We can also use the Major 7 chord, since these scales both have a Major 7 degree. This chord is name so because it is simply the continuation of stacking alternating major and minor thirds. Try it out. Start on C and go to E. That is a major third or two whole steps. Going from E to G is a minor third or a step and a half. The pattern continues with G to B as another major third or two whole steps.

Melodic Minor does not have a major chord. Instead, the degrees 1, b3, and 5 gives us a minor chord. Adding the Major 7 of the scale gives us the Minor Major 7 chord written as mMaj7. This chord is a minor third, followed by a major third, with another major third after that. Breaking the pattern of alternating thirds creates tension and this type of tension is not found in the Major Scale. By having two consecutive major thirds (Eb, G, and B) we get an augmented chord. This is what makes the mMaj7 sound so tense.

Let’s listen to these chords played in arpeggios (or broken chords). In the sound clip below I’ll play C Ion

ian with a CMaj7 and an F note (or 11th) from the next octave. Then I’ll play C Lydian with a CMaj7 and an F# note (or #11) from the next octave. I’ll finish with C Melodic Minor. To highlight the augmented chord embedded in the mMaj7 I’ll play CmMaj7, Eb+, and CmMaj7. Be sure to listen for the Major 7, which is the note B. It will be present in all three examples.

The Minor Seventh Chord

Minor seven chords are written as m7 and have the degrees 1, b3, 5, and b7. They are minor chords with a dominant seventh degree. Scales like Dorian, Aeolian, Phrygian all have these degrees as shown below.

The m7 chord does not have a lot of tension because it has alternating thirds. It is a minor third, followed by a major third, followed by another minor third. We can use this structure with all three of these scales because the degrees b3, 5, and b7 are present. This means that we can play melodies from any of these scales over a m7 chord. I’ve put another audio clip together to show off what this can do for you. I’ll start with C Dorian (C, D, Eb, F, G, A, and Bb), then go to C Aeolian (C, D, Eb, F, G, Ab, and Bb), and finish the first set with C Phrygian (C, Db, Eb, F, G, Ab, and Bb). Listen for the Cm7 chord as it will be used in all three scales. Then I’ll play D Dorian, A Aeolian, and E Phrygian. These scales have the same degrees as the diagram above, but in this second set they will all use the same notes of C, D, E, F, G, A, and B.

The first set used Cm7 and each scale gave a different sound over the same chord. The second set used different m7 chords, but the notes for each chord along with the melodies all came from the C Major Scale. Next time you play a m7 chord try a melody from Dorian, Aeolian, or Phrygian. There’s a good chance that something interesting will be heard even if the scale you pick doesn’t fit what you are playing. This is just a peak into what modulations can do for you. For now, let’s continue to the Dominant 7.

The Dominant Seventh's Tri-Tone Power

The term "Dominant Seventh" applies to an interval note and a chord form. The note is the b7. An easy way to find this note is to go one whole step down from the root note, C's b7 is Bb and G's b7 is F. The chord is a major chord with the b7 note. If we create a C Dominant 7 (written as C7), then you would use C, E, G, and Bb. The same goes for a G7, which is G, B, D, and F. This means that a Dominant 7 is a major chord with a b7 degree. This can be found in the Mixolydian scale using the degrees 1, 3, 5, and b7.

While the m7 chord uses the b7 note, the Dominant 7 chord breaks the pattern of alternating thirds and thus has noticeable tension. If we look at the G7 chord we have a major third from G to B, and then minor thirds from D to D and D to F. Like the augmented chord we saw in Melodic Minor, we now have a diminished chord in our G7 chord. This is B diminished (written as B°) or B, D, F.

The importance of this is the distance from B to F. This is an interval called the Tri-Tone, which is three whole steps or three tones. New musicians tend to avoid this interval due to its tension and an inability to understand how it functions. A good first rule to follow is that a Tri-Tone likes to resolve by going to a chord that is one half-step up from the first note of the Tri-Tone interval. If you play B˚, then B – D – F resolves to C, CMaj7, Cm, Cm7 or any other chord that has C as a root. You could resolve B° to C7 or C˚, but both of those chords contain the Tri-Tone, so the tension is unresolved.

It should be noted that resolving to a diminished chord causes some technical problems. Of course, if it somehow sounds good, then use it.

You can use the same rule for the G7 chord. G7 is G – B – D – F. Since the Tri-Tone interval still exists from B to F, we can resolve G7 to C, CMaj7, Cm, or Cm7. We can also resolve to C7 or C°, but the tension is still present.

Now tension is not something to avoid. Embrace it because it lets you move to other chords and makes them stronger. For an example let's use the C Major Scale chords C, Am, Dm, G, and finish with C. It sounds good, but if we use a G7 then the tension of the Tri-Tone makes finishing the C a stronger resolution. We can also add an E7 before the Am and an A7 before the Dm to drive the progression forward rather than letting it pull us along. Take a listen. First, I'll play C, Am, Dm, G, and resolve to C. Then I'll play |C    E7|Am   A7|Dm   |G7    |C    |. I haven't included any timing because I want you to hear the driving force of the E7, A7 and G7 chords.

You may have noticed that the chords E7 and A7 are not part of the C Major Scale. These are borrowed chords from other keys. The important thing to know is that they are the fifths of the chords they go to. E is the fifth of A, which is to say that E is a perfect fifth (three and a half steps) higher than A. The same goes for A as the fifth of D. Think of it as a 5 to 1 relationship: E7 to A and A7 to D. We could continue this and use D7 to get to G and G7 to C. If we kept going, we would continue forever with the following patten of dominant seventh chords.

C7, F7, Bb7, Eb7, Ab7, Db7, Gb7, B7, E7, A7, D7, G7, and back to C7.

Half-Diminished Sevenths

There are two common diminished seventh chords, which are the half-diminished chord or m7b5 and the fully diminished chord or ˚7. There can be a °Maj7 chord, but that will come from a more exotic scale that contains the degrees 1, b3, b5, and 7. Let’s focus on the m7b5 and °7.

The half-diminished chord can be written as m7b5 or ø. They all mean the same thing, which is that degrees 1, b3, b5, and b7 are used. You can find this structed in several diminished scales, but Locrian is the most used scale since it is the seventh mode of the Major Scale. Let’s look at B Locrian so that we stay consistent with using modes from the Major Scale.

The Bm7b5 chord uses the notes B, D, F, and A. The two minor third intervals between B and F creates the same Tri-Tone that we saw in the G7 chord. The difference is that the m7b5 structure has a major third interval between the b5 and b7 degrees. Think of this as the reverse of a Dominant 7 structure.

So how do we use this? Well one way is to realize that the Maj7 degree of a scale is called the Leading Tone for a reason. It literally leads you up to the first degree of the scale. Play C, D, E, F, G, A, and when you get to B just play B. Play it over an over for a few seconds and then go up to C. That tension and release from the Leading Tone is a great way to understand how to use any diminished chord as they all lead you somewhere.

The place that the m7b5 goes to is normally a Major or Major7 chord that is a half-step up. So Bm7b5 goes to CMaj7, F#m7b5 goes to GMaj7, and C#m7b5 goes to DMaj7. But there are some exceptions. If you resolve down a whole step, then you are essentially resolving to the relative minor. C Ionian, which is where the C Major Scale starts, has A Aeolian as its relative minor. So you could go from Bm7b5 to Am, but there will be an unresolved resolution.

Using the same chord progression from earlier of C, Am, Dm, G, and ending on C we can use the Bm7b5 in two ways. First I’ll play |C  |Am  |Dm  |G Bm7b5| C  | and then I’ll play |C  |Am  |Dm  |G |Bm7b5 |Am |Dm |G |C  |. Listen for the Bm7b5 leading up to C in the first part and then listen for it guiding us to the relative minor chord of Am where we can continue our chord progression.

Fully Diminished Inverted Possibilities

The fully diminished chord or °7 uses the degrees 1, b3, b5, and bb7. Think of the °7 notation as diminishing the b7 to create a bb7. This structure is found outside of the Major Scale. One of my favorite scales is the Diminished Scale or Aeolian b5 bb7. Notice how the bb7 causes this chord to only use minor third intervals, which are one and a half steps. There’s even a minor third from the bb7 going up to 1 in the next octave. Because of this, we can use inversions to our advantage.

An inversion is just a chord with one of the other notes as the root note, so a C Major chord with E as the root note is in 1st inversion (written as ) and using G as the root note puts the chord in second inversion (written as ). These inversions can also be named Emb6 and G6sus4. When we apply inversions to a fully diminished chord, we get a specific result.

If we use a B°7 with the notes B, D, F, and Ab and put it in any of the three inversions we get D°7, F°7, and Ab°7. This is due to the minor third being the only available interval between all these notes. This helps us out because we can use B°7, D°7, F°7, and Ab°7 as the same function. What I mean by this is that a diminished triad (not a half-diminished chord) normally goes up one half-step to a major or minor but can also go down a half-step in some situations. This means that the B°7 can resolve to a major or minor with roots Bb, C, Db, Eb, E, Gb, G, or A.

Sounds crazy right? Well listen to this progression. I’ll play B°7 arpeggiated, meaning that the notes are broken apart. This way you can hear the stacked minor third intervals. Then I’ll play a Maj7, m7, or Dominant 7 chord for each of the eight root notes that we can go to.

B°7, BbMaj7, B°7, CMaj7, B°7, Dbm7, B°7, Ebm7, B°7, Em7, B°7, GbMaj7, B°7, G7, B°7, Am7.

What has happened is that the B°7 chord’s four notes of B, D, F, and Ab can all lead up or down a half-step, giving you eight notes you can lead to.

A final use for the °7 that goes unmentioned is to use one of the notes to build a new structure. Let’s stick with B°7 for another arpeggio and when we get to the Ab we can begin to build an AbMaj7. The notes played would be B, D, F, Ab, C, Eb, and A. AbMaj7 happens to be the fourth chord of the Eb Major Scale, so we can also use EbMaj7 as the first chord. The Leading Tone of the Eb Major Scale is D, so we can use a D Diminished Triad of D, F, and Ab. These three notes are in the B°7 chord, so we can add a B as the root to get back to where we came from.

I’ll play CMaj7, Bm7b5 blending into B°7 and blending into AbMaj7, EbMaj7, D° blending into B°7 and blending back to Bm7b5, then finishing back with CMaj7. It’s quite a bit, but the point is that you can use the B°7 to change keys and come back to your original key.

Putting it to Good Use

Now it’s your turn. Try using the Maj7 and m7 chords as nice, resolved structures that help you to tell the story in your song. To help drive the story forward you can try adding in some Dominant 7 chords a fifth away from a target chord. You can also use the half-diminished chord to move up a half-step to a Maj7 or down a full step to a m7. Then there’s that ambiguous fully diminished chord. Use that tension to guide your song’s emotion to a new place and, when you are ready, bring it back home with the same fully diminished structure.