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Im analyzing a song that is in the key of e minor.

And the chords for the song are:

Em B7 Am

Now, I'm no expert but from my theory I learnt a while back for a minor key the chords are:

Minor- dim - maj - min min maj maj

So, what really confuses me is why a B7th chord is used and not a B minor 7th.

If anyone could help to explain to me that would be great.

  • In your 5th line, did you mean 'Minor' for the first word? – Tim Dec 25 '14 at 15:39
  • Good spot..edited now – Pedro Fernandez Dec 25 '14 at 16:15
  • Also have a look at this answer. – Matt L. Dec 26 '14 at 8:59
  • e moll has a D# and F# – Maika_Sakuran0miya Feb 20 at 11:32
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It's the old chestnut that stems from the fact that tunes in minor keys can, and do, use three different sets of notes. The three sets of notes (scales) are natural minor, harmonic minor and melodic minor. The lowest 5 notes for all are the same, but the natural minor uses the notes 6 and 7 that are found in its relative major. As in your key of Em, note 6 is C, note 7, D. Using the harmonic minor, note 6 is C, while 7 is D#.In the melodic, 6 is C# and 7 is D#. Sometimes the melodic reverts to the natural minor notes as well. Not discussing that here.

As chords are made from the notes found in scales, there is the chance that the B chord will be made from B, D# and F#, found in both the melodic and harmonic scales. So, in a minor tune, the V chord could end up as Bm7 OR B7, depending on the melody line (and the composer!)

  • Any key can use any set of notes… Major: Lowering 6th and 7th, Minor: Raising 3rd, 6th, 7th, Lowering 2nd, Both: Raising 4th (those are common non diatonic notes used) – bjb568 Dec 25 '14 at 19:20
  • Bm7 would be a bit unusual in most styles, though, at least from what I hear. Bm, sure, but the sept chord is largely reserved for major chords. – Christopher Creutzig Dec 30 '14 at 1:44
  • @bjb568 - Once 'any key' uses a set of notes, that set becomes diatonic with that stated key. When certain notes are changed from that, it becomes a different key. I don't understand the point you have stated. – Tim Feb 3 '15 at 18:31
  • V/V (five of five) in C major is D. It contains F# which is non-diatonic. That doesn't mean you're not still in C. – bjb568 Feb 3 '15 at 18:51
  • @bjb568 - you've said it. VofV is to put it into V. Otherwise it wouldn't be V - of V. Mostly, when F# occurs in C, the next part is effectively in G (the V). – Tim Feb 3 '15 at 19:02
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Note that the "reason" for having different sets of minor scales is that (in your example of an E (minor) piece) D# so much more begs for becoming an E than D does. Thus, the B major chord (which differs from the minor one through D->D#) creates more harmonic tension. The scale that you get by replacing D->D# is called the harmonic scale. However, the harmonic scale has an "unmelodic" 3 half-steps gap between C and D# and if you also want to fix this you end up with the so called melodic scale.

In conclusion, the B major (within an E minor piece) has more harmonic tension (D# is "heard to be begging for realease in E") than the B minor. This still with added 7 (which itself also creates tension)

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To add to the above replies, it is very common in both classical and contemporary music for the V chord to be major. You'll see this everywhere; a great example is Beethoven's Symphony 7:II (third chord in the initial progression), and also "Greensleeves" (at the end of its phrases).

You wrote:

Minor- dim - maj - min min maj maj

You are correct when strictly following the key signature. The major V in minor mode has an altered seventh scale degree (i.e., from te to ti), and thus it uses the leading tone, which provides tension.

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The root of B7 (b) is a perfect fifth above the root of Em (e). Usually when you have a dominant 7th chord played before or after another chord whose root is a fifth below, then it functions as a dominant for that target;

B7 (dominant) --> Em (target)

If the dominant is not diatonic to the key of the target (not part of the same scale), then it's referred to as a "secondary dominant." In your example, the diatonic B chord would be Bm7, but making it a dominant 7th reinforces the tonality of the Em chord. This is a very common thing to use, both in popular music and in traditional classical music.

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Tim's answer is a great explanation, looked at from the perspective of the melody. Depending on how you learn and understand music it will be easier for some people to see it from the perspective of the chords. This will expand on the correct observations of Michael and Bananach.

I use uppercase roman numerals, remember minus (-) means minor.

We have 5 Qualities of chords, grouped into families by how they sound. We'll just use the 3 most common for this:

  1. Major- Sounds big, bright, bold
  2. Minor- Dark, smooth
  3. Dominant 7th (or just 7th)-Tense, Jarring, (Funky or Bluesy)

Chords have 1 of 3 Jobs (or functions) based on their numerical position of their root note in the scale (we are counting the letters):

  • I,III,VI create Stability (Official Title is **Tonic* Function*)
  • II, IV create contrast (Subdominant Function)
  • V, VII create Tension (Dominant Function)

The chords' function is based on their number, regardless of being flatted or sharped. A III-7 chord in Major creates stability, so does a bIII chord in Minor Key.

Here's why we change the V- chord to V7: The job of a V chord is to create tension, and go back to the I chord. This is the most critical job in music. The fifth chord of natural minor is minor, so it sounds dark and smooth.

It creates some tension, but why settle when we have a chord that's more or less born to do the job? The Dominant 7th chord. Its even named after its job. We replace the minor chord with a chord who naturally sounds tense all by itself to do the job and create tension. Its job is so important, that if we say 7th chord, its assumed we mean the dominant seventh chord not any other kind.

Another analogy: If your song was a cheesy summer action movie, at the height of the dramatic structure, the big shootout at the end, are you going to send your sissy pretty boy actor to jump out of a flaming helicopter? No, you bring in a stuntman who lives for danger.

What it takes to make a minor7 chord into a dominant 7th chord is raising one note (the third of the V chord). That note is the same note as the seventh of the natural minor, changing it to harmonic minor.

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It is B7 because it is derived from the harmonic minor scale. The harmonic minor scale is used to give us access to the dominant chords typically used to establish the key. If it was Bm7, it would not really have dominant function, regardless of its degree name.

Here are the diatonic 7th chords in e-minor:

  1. EmM7, minor-Major 7th chord
  2. F#m7 b5, diminished-minor 7th chord
  3. G#augM7, Augmented-Major 7th chord
  4. Am7, minor-minor 7th chord
  5. B7, Major-minor 7th chord
  6. CM7, Major-Major 7th chord
  7. D#dim7, diminished-diminished 7th chord
  • Because E minor has C, C#, D and D#, other 7th chords are also available. Em7, A(dom)7th, D(dom)7th F#m7, C#m7b5 for examples. – Tim Dec 10 '18 at 16:26

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