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Chord formation exercise - D7

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(@thegrimm)
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Joined: 19 years ago
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Topic starter  

Whenever I come across a new chord in music, I try and work out the chord formation myself before looking it up (it's a good way to develop my theory skills).

Now, I can't work out what i'm doing wrong with the D7 chord. When I look it up, I get xx0212. But I work out x00212. Which doesn't even seem to be suggested as an alternative voicing.

Step 1: D7 is a flat 7th, therefor the 1st, major 3rd, 5th and flat 7th should be the notes required, on the D major scale.

Step 2: On the D-scale, I get D, F#,A and C as the corresponding notes.

Step 3: Using my guitar tuning EADGBE, I derive x00212 or even 200212.

Is there some reason why I can't play the low E on fret 2 or the open A string? Just a convention? Am I missing a vital step of theory?

Thanks in advance


   
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(@anonymous)
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Joined: 17 years ago
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If your looking for some theory , check out lesson by david hamburger for naming chord shapes -

http://acousticguitar.com/lessons/Chord_Names/1.html
http://acousticguitar.com/lessons/Chord_Names2/1.html


   
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(@kingpatzer)
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Whenever I come across a new chord in music, I try and work out the chord formation myself before looking it up (it's a good way to develop my theory skills).

Now, I can't work out what i'm doing wrong with the D7 chord. When I look it up, I get xx0212. But I work out x00212. Which doesn't even seem to be suggested as an alternative voicing.

Step 1: D7 is a flat 7th, therefor the 1st, major 3rd, 5th and flat 7th should be the notes required, on the D major scale.

Step 2: On the D-scale, I get D, F#,A and C as the corresponding notes.

Step 3: Using my guitar tuning EADGBE, I derive x00212 or even 200212.

Is there some reason why I can't play the low E on fret 2 or the open A string? Just a convention? Am I missing a vital step of theory?

Thanks in advance

You're right that those are both possibilities. So why not play that open A?

Well, the biggest reason not to is that you want to emphasise the "D-ness" of the chord. By having the lowest note be the tonic, the ear tends to categorize the chord correctly.

The other reason is that the 5 isn't that important in a 7 chord. You need the 3 to tell you if it's major or minor, and you need the b7 to tell you it's a 7 chord. But you don't really need the 5. You already have the 5 once in the chord, and doubling up on that note won't make the chord sound better, it'll just mask what's going on.

So no, there's no reason why you can't play the open-A. But practice will suggest that it's often best not to. Sometimes the effect you'll get is just what you want, but most often it isn't.

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(@greybeard)
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Strictly speaking x00212 is a D7/A, because you no longer have the tonic as the lowest note - 2nd Inversion as lowest note is the V.
200212 is actually a D7/F#, the 1st inversion, as the lowest note is the iii.

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(@noteboat)
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You're not going wrong.

Chord books (and chord java finders) will give you the common voicings. Even chord encyclopedias are far from exhaustive - if you want exhaustive, check out Chord Chemistry... Ted Greene shows pages voicings for A and E chords, and leaves it to you to work out the others.

Here are a dozen D7 shapes I commonly use... there are lots of others you can stretch for when you need them (if you know the fingerboard):

-2-2-2-x-x-5-5-8-x-x--10-10-
-1-1-1-3-3-3-7-7-7-10-10-10-
-2-2-2-5-5-5-5-7-7-11-11-11-
-0-0-0-4-4-4-7-7-7-10-10-10-
-x-0-x-5-x-x-5-x-x-x--x--12-
-x-x-2-x-5-x-x-x-8-10-x--10-

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(@thegrimm)
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Joined: 19 years ago
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Topic starter  

Woa. That's as many D chords as I know chords, total :D

How would one play 2X0212, exactly? By muting the A-string, I presume? Or on alternate strums?


   
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(@noteboat)
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I mute the A string.

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(@chris-c)
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The other reason is that the 5 isn't that important in a 7 chord. You need the 3 to tell you if it's major or minor, and you need the b7 to tell you it's a 7 chord. But you don't really need the 5. You already have the 5 once in the chord, and doubling up on that note won't make the chord sound better, it'll just mask what's going on.

A classic example of this is the chord that you'll find shown as C7 in pretty much all the chord books. It's usually shown as 032310.

I have a guitar book which shows this pattern and then says:

The C7 chord will always contain C(1), E(3), G(5) and Bflat(7), but it is possible to arrange these notes in any order

Most guitar books say something similar. But if the author (or reader) actually looked at the so called C7 - there's no G in it at all! It goes E,C,E, Bflat, C and yet another E. Three Es but no G!

Funnily enough, I've yet to see an author actually mention this fact, or offer any reason why the G was missing. :)

Is there a fancy name for a C7 with no G in it? "C7 reduced" "C7 not quite all there" ??? Or what? :?


   
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(@noteboat)
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Well, you can include the G if you want it by fingering the moveable form xx2313.... that's the voicing I showed in my book to avoid the confusion :) but it's still C7 either way.

With chords you've got theory (stacking thirds) and practical application (chords with more than 4 different notes are very, very rare). So at some point, something's got to give - a 9th chord has 5 notes; your voicings will be very limited if you include them all.... and 13th chords would be impossible, as they contain more notes than you have strings.

When you work out voicings to play, certain notes are required, others are nice to have, and the rest are disposable.

The required tones:

- The 'highest' note in the chord (formula-wise). Not much sense calling it a ninth chord if you don't play a ninth.

- The seventh tone, if a chord formula has more than four notes. Dominant chords always contain a b7; extensions of major chords always contain natural 7. Minor chord extensions can go either way, as in m7 or m/Maj7, but it's got to have a seventh. If you decide to skip the seventh, you change the name of the chord - C13 becomes C6, ninths and elevenths become 'add9' or 'add11'.

- The third, for 7th and 9th chords. That lets you know if it's major or minor. When you get to 11ths and 13ths, the chords will sound major if you don't include a 3rd, so they drop into the 'nice to have' category.

- Any altered tones. For C9+, you'll need the #5, etc.

-Other tones to fill it out. You need at least three tones for it to be a chord, instead of just an interval ("power chords" aren't really chords). So if you're playing a 7th chord, you've already got the 7th and 3rd required - you still need a root OR a fifth.

The 'nice to have' tones:

- Roots. Believe it or not, you don't need a root for a guitar voicing, and it's common to drop them for chords like 11ths and 13ths. That can be really confusing, since it's the root that names the chord! But this is practice vs. theory... in practice, in a Dm9 - G13 - Cmaj7 change, you'll hear the G even if it isn't present in the G13 chord.

- Fifths. They make chords sound 'full', but the really add little harmonically. So in the case of that C7, you hear C7 with or without the G.

The optional tones:

- Anything else. For C13, the required notes are A, Bb, and at least one other tone; the 'nice to haves' are C and E. That leaves G, D, and F as the ugly stepchildren.

So in theory, a seventh chord contains 1-3-5-b7. In practice, you can play these tones, or just 1-3-b7. You can even play 3-5-b7 - try playing the Eº triad in place of C7, and you'll find it sounds ok - but explaining it in those terms would be way too confusing for a basic explanation on moveable chords.

If you're still confused by it, realize that chord names are just a way to categorize sounds. Composers don't think in terms of chords the way a guitarist does - they're thinking of interacting melody lines. Theorists look at these simultaneous melodies 'vertically' and assign the chord names as a way of explaining what's happening, to put the sounds within a framework to compare to something else. If one composer uses C-E-Bb and another uses C-E-G-Bb, the results will sound nearly identical - so the chord names are the same.

Chord names were never intended to be a road map to exact tones. Many guitarists don't know this, so you see garbage like G/B in chord charts all the time... unless that B is part of a moving bass line, feel free to ignore it and play whatever G inversion you'd like. That's what I do, and no band leader has ever called me on it :)

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(@nicktorres)
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Ted Greene's book is exhausting to read. Thorough, but exhausting.


   
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(@chris-c)
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Well, you can include the G if you want it by fingering the moveable form xx2313.... that's the voicing I showed in my book to avoid the confusion :) but it's still C7 either way.

snip

Thanks NoteBoat for taking the time to post such a great reply! :D Wonderful stuff for this beginner to read.

I've copied it and pasted into my music notes. Hope that's OK.

After spotting that the G was missing I fiddled about for a while trying to find a shape that did include it, and the xx2313 that you mentioned was exactly the one that I found. So I hunted through my various books and bookmarked chord sites to see if anybody listed that shape. To my surprise I couldn't find it anywhere. Obviously, I should have had your book. :oops:

Of course, the "usual" C7 sounds fine anyway, so what does it matter. But it surprised me that all my books quoted what seemed to be conflicting stories (i.e "this is always the formula" and then showed an example that disproved the statement with no explanatory comment!).

Thanks again for a great post with not only the C7 answer, but also a stack of excellent information about some of the other chords that are still "just down the road apiece" from me too! :D


   
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