[ijh]

OK just when i think i'm getting the hang of a bit of theory!

I'm sitting here trying to work out they key for a song - it end's on G, so i figure the key of G is a good place to start.

It also has a Bm (a iii chord) ok, ok, looking good, a C(IV) and a D(V) an Am (ii). Great, must be in G then....hmm what's this, an F!

So where does F come from? Can you just chuck in a random chord from another key?

I've another simple song with a G, D, C, G progression, but then there'll be a D7 inserted after the D sometimes? Hows does this work?

Is it still the same key? And are there some rules to this adding of out of key chords?

[Aunt Doty]

Go to the Main forum and look at the thread confused with Chord building under The Art of improvisation and I think it will answer your question!

[Fretsource]

Basically, yes, you CAN throw in an out of key chord. It can add spice, surprise - or a whole host of other interesting effects if chosen carefully.
Most music styles frequently use 'out of key' chords. Very simple songs such as nursery rhymes rarely use anything out of key - Folk and C&W do sometimes, but not so often. Jazz does it all the time. I don't know any jazz song that stays in key - It wouldn't sound jazzy if it did. Even simple Blues uses out of key chords.

By the way, D7 is very much an IN KEY chord (of G major). What made you think it wasn't?

[allthumbs]

The F is indeed out of the Key of G. The 7th chord in the Key of G is a F# dim. So while it is an outside chord. It is close enough to work.

[Kirk Lorange]

Hi ijh. As you get more and more into the structure of music, you'll begin to recognize these deviations from the diatonic, like the F chord in the key of G. In many of the lessons I post here, I show examples of others, such as turning the usual minors into majors, or the opposite, turning some (usually the IV chord) of the majors into minors. It really is strictly up to the person composing the tune what chords are used, and more often than not, the modern composers of pop music don't know anything about those related chords ... they just experiment away and settle on chords that sound good together. Naturally, those 7 chords that arise naturally out of the major scale sound good, but other do as well, such as the F in the key of G.

You can easily file these away mentally using the Roman numeral method. That way you can recognize them in other tunes and use them if you want to write your own tunes. The F in G would be bVII, so you can quickly see that it's a major chord (capital) built on the flat 7th degree of the scale, in this case F. Once you start thinking along these lines, you'll see similarities everywhere, and you'll also be able to simply hear those chords and know what they are without even thinking about it.

The main thing to remember though is that 'outside' chords can and do come into play all the time, but if 4 or 5 are from a certain key and 1 isn't, go with the majority. And, while knowing the key is very important to know, it's more important to know the 'Chord of the Moment' ... to my way of thinking, anyway. I know of many tunes where the key is not awfully apparent, but they're great tunes, the Rolling Stones' 'Brown Sugar', for example. The 'verse' section of that tune is C F and Bb, which looks to be the key of F in a V - I - IV sequence, but it's not; the chorus brings in a G7 which is an obvious V chord of C, so in fact it's in C and that Bb chord is the chord you mention: a bVII.

[Tekker]

Originally Posted by ijh

I've another simple song with a G, D, C, G progression, but then there'll be a D7 inserted after the D sometimes? Hows does this work?

Is it still the same key? And are there some rules to this adding of out of key chords?

The D7 is actually in the key of G. It is an extended chord, which adds the 7th onto the D chord.

When you build the D chord you have to use the notes from the G major scale:
G A B C D E F#

If you build a 7th chord starting on D (using the "stacking 3rds" method), you will get the following notes:
D F# A C

These notes are the notes in a D7 chord. So D7 is in fact in the key of G. This one's by the book.


If any of this is confusing, be sure to check out the theory lessons in the member's lessons section located here.

-tkr

[ijh]

Originally Posted by Tekker

The D7 is actually in the key of G. It is an extended chord, which adds the 7th onto the D chord.

Ah ok so i can extend the basic Maj or Min chords from the key to produce extensions. Does this include sus chords then? Could i include a Dsus2 or Dsus4 in that case then?

[Tekker]

Originally Posted by ijh

Ah ok so i can extend the basic Maj or Min chords from the key to produce extensions.

Yep. As long as those extensions fit the key (as explained below...)

Does this include sus chords then? Could i include a Dsus2 or Dsus4 in that case then?

If you are trying to follow the key (using only chords that contain notes found in the key), then you want to make sure that whatever note(s) you are adding or changing are in the key as well.

Using your two examples:

Dsus2 = D E A
D, E, and A are in the key of G.

Dsus4 = D G A
D, G, and A are also in the key of G.

So, both Dsus2 and Dsus4 can be used in the key of G.


If you ever have any question as to whether a certain chord or extension will work in a key:

1) Write out all the notes in the scale for whatever key you're in (in this case the G major scale is used because we are in the key of G major).

2) Write out all the notes of the chord in question (as I did above fore Dsus2 and Dsus4).

3) Compare the notes in the chord with the notes in the scale. If all the notes match, then the chord falls within the key. If you have any notes that do not match the scale, the chord is not in the key.


Here's an example of a chord that DOESN'T fit in the key of G major.

Csus4 = C F G

Comparing this to the G major scale, we can see that C and G both match the scale, but Csus4 has an F note while the G major scale has an F# note (not F). Therefore this chord does not fit within the key.


This process can be applied for any chord you are interested in and it will tell you whether or not it fits within the key.

Hope that helps.

-tkr

[ijh]

Aha! I get it now. Thanks very much for the replies.

[skinnybloke]

Tekker....You are an absolute gem!

[Aunt Doty]

Thanks Tekker for all your knowledge and info! I've got to study further, some of this I understand and some of it like sus notes lose me!

[felixdcat]

Key changes can happen any time - one way of doing this:

C - F - Em - F#m - D - G

The first part is in C, and since they share the Em chord, the second part is in D.