8

Consider for instance the following chord (C7) :

  • C E G Bb
  • E G Bb C
  • G Bb C E
  • Bb C E G

How can I number these inversions? I remember it was something with a '+'.

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    Just take note that these numbering is part of any seventh chord not just the ones built on the fifth scale degree (Dominant) My answer counts just as much for the Super Tonic chord with it's seventh and the Leading tone seventh as well. – Neil Meyer Feb 19 '16 at 19:11
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    I cannot for the life of me remember what this is a dupe of but I have answered this before on this site.. – Neil Meyer Feb 19 '16 at 19:14
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    Here's a good overview of figured bass notation (which is the sort of notation that basso continuo uses). – BobRodes Feb 19 '16 at 22:57
  • Sorry if it is a duplicate. I checked it and did not find it, but I am new to this SE. – Karlo Feb 21 '16 at 10:32
5

It's just basic figured bass which on the V chord in a major key would look like:

  • Root position: V7
  • First inversion: V65
  • Second inversion: V43
  • Third inversion: V42

The above is attached to a Roman Numeral for demonstrations, but would be omitted if you were just doing the figured bass. Figured bass is always built off the key so all the notes used above are strictly within the key. If you need to alter notes of the key to represent it then you would need to use a "+" or a slash though the number that represents the desired pitch to raise it and a "-" in the same fashion to lower it.

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  • If I am correct, these refer to a major seventh chord (e.g. c e g b natural) instead of a dominant seventh chord (e.g. c e g bflat). – Karlo Feb 19 '16 at 14:00
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    @MWijnand it's both. If your key has C, E, G, and Bb in it it will be dominant and if it has C, E, G, and B it will be a major 7th or if your key has C, Eb, G, and Bb it will be a minor 7th. I say in my answer "If you need to alter a chord tones to represent it then you would need to use a + or a slash to raise it and a - to lower it." which is what you need to do if it is not in the key. – Dom♦ Feb 19 '16 at 14:13
  • OK. So how would you number the inversions of the dominanth 7th on G (with F natural) if you are in C major (no key), to distinguish from the major seventh (with F sharp)? – Karlo Feb 19 '16 at 14:48
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    @MWijnand On every inversion but the Third you would put a - next to the lowered tone. So -7 for root, -5 for first, and -3 for second. Third has the tone in the bass already altered so you don't have to do anything to it. – Dom♦ Feb 19 '16 at 14:50
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    @NeilMeyer I would think so too, but I don't see anything here that has to do with a jazz harmony approach. Dom's explanation is straightforward figured bass notation, isn't it? Although I haven't seen a - instead of a flat symbol before, since it is hard to distinguish from a suspension, e.g. 7 - 6. – BobRodes Feb 19 '16 at 23:10
3

The numbering stems from the way in which you count from the lowest note up. Lets take those examples you mention. It is good to understand the reasoning behind it so as it not to become a memory exercise.

F major's dominant seventh chord (ie. C7) in root position.

F7

Now let us count from the bottom note. It is C then the next note is E. That is a third. Then we have E to G that is a third again or a fifth from the root. Lastly we have G - Bb. That is a third again and the seventh from the root.

So we have 3, 5 and 7 when you count from the bottom note (The root.) That is why the full notation for a seventh chord in root position is 7/5/3. Most of the time like it is in this case it is just plain V:7

F Major's dominant seventh chord in first inversion.

F6/5

Now we have the first inversion chord so the E is in the bass. Lets do the same again. E-G is a third. E - Bb is a fifth and E - C is a sixth. Three, five and six. Hence the notation 6/5/3 or more commonly just 6/5.

F Major's dominant seventh chord in second inversion.

F 4/3

Now we have the second inversion chord. Now the G is in the bass. Let us count again. G-Bb is a third. G-C is a fourth and G-E is a sixth. So we have 3, 4 and 6.

Hang on to your hats now we cannot call the second inversion seventh chord a 6/4. that name is already taken by our regular triads in second inversion. So we call it V:4/3 instead.

F Major's dominant seventh chord in third inversion.

F 4/2

So the third inversion chord. We start on Bb-C a second. Bb-E a fourth and Bb-G a sixth. So we have 2, 4 and 6. Still we cannot call it a 6/4 chord so we instead call it a 4/2 chord.

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  • I think it's talking about C7 as the dominant in the key of F major. But I agree it could be more clear. – luser droog Feb 19 '16 at 22:40
  • @luserdroog I misread it.C7 is the domination chord in F, but the way it's written in this answer it's never mentioned, but F is. – Dom♦ Feb 19 '16 at 22:47
  • I gave an edit. Consistent possessives, a parenthetical. I wonder if "dominant's" would be better. – luser droog Feb 19 '16 at 22:58

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