Unveiling the Half-Diminished Chord: The Minor 7 Flat 5
- The American Guitar Academy
- 2 days ago
- 6 min read
In the vast and colorful world of music theory, certain chords possess a mystique that sets them apart. One such chord is the "minor 7 flat 5" (m7♭5) or "half-diminished" chord. Despite its foreboding name, this chord is quite common in both jazz and classical music, weaving a delicate thread of tension and resolution through countless compositions. Let's dive into the fascinating characteristics of the half-diminished chord, its construction, common appearances, and practical applications, especially on the guitar. We hope this article helps demystify the half-diminished chord so that you can approach it with confidence.
The Anatomy of the Half-Diminished Chord
To understand the half-diminished chord, let's first break down its structure. Just as the name implied it can be thought of as a minor seventh chord with a flatted fifth. It can also be thought of as a diminished 7th chord with a flatted seventh instead of a diminished seventh. Traditionally, old school swing jazz players thought of it as a minor 6th chord in the 3rd inversion. Regardless of how you conceptualize it, the chord consists of these four notes:
1. Root (1st): The starting note of the chord.
2. Minor Third (♭3): Three half-steps above the root.
3. Diminished Fifth (♭5): Six half-steps above the root.
4. Minor Seventh (♭7): Ten half-steps above the root.
For example, in a Bm7♭5 chord:
- The root is B.
- The minor third is D.
- The diminished fifth is F.
- The minor seventh is A.
This combination of intervals creates a chord that prepares the listener for a dissonance, providing a pivotal moment in many harmonic progressions. This chord is the start of a minor cadence which is one of the most common chord progressions.
Where do we find the Half-Diminished chord?
The half-diminished chord is a vital component in both major and minor keys, providing essential harmonic functions that enhance musical expression. Its strategic placement within chord progressions allow it to set-up cadences in new keys and facilitate smooth transitions to different musical destinations. Understanding where and how the half-diminished chord appears in different keys is crucial for any musician aiming to deepen their harmonic vocabulary.
In Major Keys:
In major keys, the half-diminished chord typically emerges on the seventh degree of the scale. The seventh scale degree is B, The B half-diminished chord (Bm7♭5) consists of the notes B, D, F, and A. All notes found within the C major scale. This is the only half-diminished chord that can be found using the diatonic notes. (Diatonic means “notes in the key”)
The chord creates a unique pre-dominant function, leading naturally to the III7 chord which takes us to the relative minor key. In other words, it prepares us to move from I (major) to vi- (minor). For example, in the key of C major, the Bm7b5 chord takes us to the key of A minor like this: C > Bm7b5 > E7 > Am. This chord progression is called a “minor ii-Vi-i” or a “minor cadence” and can be found in countless jazz standards including beginner favorites such as, “Autumn Leaves”, “Fly Me to the Moon”, and “There Will Never Be Another You”.
Going to the vi minor:
vii-7b5 > III7 > vi-
Bm7b5 > E7 > Am
Although it contains notes from outside the key, the chord can also be commonly be found on the 3rd scale degree and on the #4 scale degree. These half-diminished chords set up cadences to the other common diatonic minor chords. For example:
Going to the ii minor:
iii-5b7 > VI7 > ii-
Em7b5 > A7 > Dm
Going to the iii minor:
#iv-7b5 > VII7 > iii-
F#m7b5 > B7 > Em
By learning these 3 half-diminished chords, you will be able to smoothly transition to the most commonly used minor key centers. Most jazz standards will typically use at least one of these and (sometimes use all 3) in a single 32 bar song. So, they are some of the most common chords you will find when playing jazz standards.
In Minor Keys:
In minor keys, the half-diminished chord takes on a similar role allowing us to play cadences that harmonize the most common minor chords. Notice how these are the same chords as in the key of C major! For instance, in the key of A minor:
Going to i minor:
ii-7b5 > V7 > i
Bm7b5 > E7 > Am
In this context, the half-diminished chord often functions as the iiø7 chord, leading into the dominant (V) and then resolving to the tonic (i). A typical progression (iiø7 - V7 - i), which in A minor would be Bm7♭5 - E7 - Am. This progression is fundamental to the harmonic language of minor keys. The half-diminished chord's ability to convey a sense of anticipation and its natural pull towards resolution makes it an indispensable tool for composers and performers. Here are the other common usages in the minor key:
Going to iv minor:
v-7b5 > I7 > iv-
Em7b5 > A7 > Dm
Going to v minor:
vi-7b5 > II7 > v-
F#m7b5 > B7 > Em
However, there is another common usage of the half-diminished chord in the minor key, and that is its role in the “minor turnaround”. A minor turnaround contains a half-diminished chord on the natural 6th degree and on the 2nd degree. It can be looped endlessly for a cool sounding minor jazz sound.
The Minor Turnaround:
i- > vi-7b5 > ii-7b5 > V7
Am > F#m7b5 > Bm7b5 > E7
There are many popular standards that are built off the minor turnaround progression such as, “Softly, As in a Morning Sunrise”, “Moanin’”, “Alone Together”, and “Lullaby of Birdland”.
The Versatility of the Half-Diminished Chord:
The appearance of the half-diminished chord in both major and minor contexts highlights its versatility. By understanding the half-diminished chord's place within the framework of major and minor keys, musicians can better appreciate its harmonic significance and incorporate it more effectively into their playing and compositions. Whether you're navigating the lush landscapes of jazz, exploring the emotive depths of classical music, or crafting contemporary tunes, the half-diminished chord remains a powerful and expressive tool in your musical arsenal.
Famous Standards Featuring the Half-Diminished Chord
Many jazz standards and classical pieces feature the half-diminished chord. Notable examples include:
"Stella by Starlight" by Victor Young: This standard contains several instances of the half-diminished chord, showcasing its atmospheric quality and versatility.
"Sotly, As in a Morning Sunrise" by Oscar Hammerstein II: The minor turnaround appears in a loop on the A section, allowing us to get comfortable with the common progression.
“What Is This Thing Called Love” by Cole Porter, a common minor key tune. The A section features cadences to the iv and i prominently. Great for learning the minor ii -V - i progression.
Common Fingerings on Guitar
For guitarists, mastering the half-diminished chord can add a new dimension to their playing. Here are a few common shapes for the Bm7♭5 chord:
1. Root on the 5th String (A String):
```
e|--------
B|---3---
G|---2---
D|---3---
A|---2---
E|--------
```
2. Root on the 6th String (E String):
```
e|--------
B|---6---
G|---7---
D|---7---
A|---x---
E|---7---
```
3. Root on the 4th String (D String):
```
e |---10---
B|---10--
G|---10--
D|---9---
A |-------
E|-------
```
These shapes can be moved up and down the neck to form other half-diminished chords.
Shortcuts for Finding the Half-Diminished Chord
A handy shortcut for finding the half-diminished chord is to start with a minor seventh chord and lower the fifth by one half-step. For example, to find Bm7♭5 from a Bm7:
1. Locate the Bm7 chord: B, D, F#, A.
2. Lower the fifth (F#) by a half-step to F.
Another common technique is to think of a minor 6th chord instead. The minor 6th chord and the half-diminished chord share the same structure with a different bass note. For instance, in the key of C major, the Bm7b5 chord shares the same notes as Dm6. Since many musicians are comfortable with the minor triads, this can be a handy shortcut once you become familiar with the relationship between these two chords.
Dm6 = Bm7b5
Gm6 = Em7b5
Am6 = F#m7b5
Get in There and Play Some Songs!
The half-diminished chord, with its rich, complex sound, is a cornerstone of sophisticated harmonic progressions. Whether you're exploring jazz standards or classical masterpieces, understanding and utilizing this chord can significantly enhance your musical expression. Its presence in major and minor keys, vital role in various progressions, and frequent use in famous compositions make it an essential tool for any musician.
For guitarists, mastering common fingerings and shortcuts for locating the chord can open up new avenues of creativity. So, whether you're playing "Stella by Starlight" or crafting your own compositions, let the minor 7 flat 5 chord enrich your musical palette, adding depth and intrigue to your harmonic journeys.