[hb]

I guess I've missed the deviance in these chords every since I started playing over 2 years ago and would like some help in identifying the difference in the structure of these chords. I had always thought that if a chord was, say a G, it was really a G major chord. But after looking, I see that there is a difference between a G7 and a G-major 7th. I guess I had always thought that when you see a G7, it was just short for Gmaj7th, but I guess I'm wrong. Can someone elaborate?
Thanks in advance,
hb

[allthumbs]

It is my understanding that a chord followed by a 7 is considered a 7th chord with a b7. A Chord designated as a major 7 has a natural 7 as an extension.

[Doug]

Yes - Marty's right. I guess because b7's were more common and in use before jazz chords came out, the term 7th referred to the flat 7th. They use the term major 7th to denote a natural 7th - 1/2 tone below the root. A beautiful sounding jazz chord.

[hb]

So, G means G major, but G7 does not mean G major 7th. Am I correct?
And if so, why?
hb

[Doug]

well, a G7th means a Gmajor with a b7th. This was the common usage of 7th chords so there was no need to specify the b7th - it was implied. It is only when the natural 7th chords started to be used that they had to denote the difference and so they call these chords "major" 7ths. Unless you're dealing with jazz, you don't normally run across major 7th chords, although they're becoming more common.
The normal 7th chord (b7th), when played as the fifth of the scale, has an important function. It pulls very strongly back to the root. And when played other than the fifth of the scale, can be used to modulate to another key.
But wait 'til you've heard from Fretsource to get the definitive lowdown...

[Fretsource]

What Doug said
The first use of 7ths was on the Dominant (or 5th) scale degree (hence the name Dominant 7th)

G7 (GBDF) is the Dominant 7th of C major and when you see it laid out in that context (over 2 octaves), then the 7th isn't flat but natural (i.e., belongs to the scale).

C D E F G A B C D E F G A B C

Counting G as 1, B = 3 D = 5 and F= 7 in that context

But if you think of G7 built on scale degree 1 of the G major scale G A B C D E F# G instead of scale degree 5 of the C major scale, then in that context the 7th note is F# - to make the 7th F we have to "flat" the F# - so the chord formula is 1 3 5 b7.

Now all chords are referred to in relation to the FIRST degree of the scale for convenience and consistency.

[allthumbs]

What fret said. hehe

[hb]

Thanks to all for clearing that up for me.
hb

[Noodler]

As an extension to that query, a major 9th also has a natural (non-flattened) 7th note too.

^^^ weak attempt at humour.

Here's an excellent link for looking up chords you're unsure of (I've favourited it):

Major 7th Chords, and all about Guitar Chords

Or for an index of them:

Browse Chord Mine by Chord Types

What a great link.

So it seems to go like this:

13th = 1,3,5,b7,9,11,13
Major 13th = 1,3,5,7,9,11,13
Minor 13th = 1,b3,5,b7,9,11,13

So what's the rule of thumb? It seems to be that if you are playing simple chords, the Major refers to the natural 3rd (3), but if you are playing extensions ie chords with a 7th and more notes, the major refers to the natural 7th (7). Is that always true?

[Kirk Lorange]

That's all well covered in PlaneTalk, hb, both the book and the DVD.

[Fretsource]

Originally Posted by Noodler

It seems to be that if you are playing simple chords, the Major refers to the natural 3rd (3), but if you are playing extensions ie chords with a 7th and more notes, the major refers to the natural 7th (7). Is that always true?

Yep - I'd say that's always true Noodler - at least, I can't think of any exceptions.