Skip to content
Figuring out the ke...
 
Notifications
Clear all

Figuring out the key

12 Posts
7 Users
0 Likes
3,543 Views
(@macca)
Active Member
Joined: 22 years ago
Posts: 5
Topic starter  

I know that the easy way to figure out what key a song is in is to find the hord the song resolves to. but this question is a bit deeper than that.

Ive been playing around with a chord progression of 3-4 chords and am not sure where to take it from here. I waqnt to keep it in the same key but am not sure what key its in.

the chords are:
G/B - C - G (thats G with a B bass - C - G)

G/B - C - Em

So Im looking for the change. Want to keep it in key. How do I now what key its in and what chords are in that key?

- Rugby League - The Greatest Team Sport on Earth. You just don't know it yet.
http://www.amnrl.com


   
Quote
(@minotaur)
Noble Member
Joined: 16 years ago
Posts: 1089
 

The alignment is poor, sorry.

The key is C. Em is the iii chord of the key of C. So your progression is V I iii. You can use Dm, F, Am or B. You can even make a momentary key change to anything you like. Just listen to how it sounds.

Here are the natural major keys and the chords in them.

I ii iii IV V vi vii
Maj m m Maj Maj m 1/2 Dim.

C D E F G A B
G A B C D E F#
D E F# G A B C#
A B C# D E F# G#
E F# G# A B C# D#
B C# D# E F# G# A#
F# G# A# B C# D# E#
F G A Bb C D E
Bb C D Eb F G A
Eb F G Ab Bb C D
Ab Bb C Db Eb F G
Db Eb F Gb Ab Bb C

It is difficult to answer when one does not understand the question.


   
ReplyQuote
(@noteboat)
Illustrious Member
Joined: 21 years ago
Posts: 4921
 

I wouldn't be so sure about the key of C. My money's on the key of G.

As the OP noted, the easiest way to find the key is to identify the chord of resolution. But resolution implies a preceding tension - usually a dominant chord type - and this progression doesn't have one.

That makes identifying "key" a bit harder. But we can narrow the field by doing it in two steps.

First we look at the tonality of the piece: what notes are being used. The chords are:

G: G-B-D
C: C-E-G
Em: E-G-B

Line up all those notes to form a scale, and we get B-C-D-E-G. There are no A notes, and no F notes, in any of the chords.

Assuming we're in a diatonic key, which isn't a big leap given only these chords, the F could be natural (key signature of C) or sharp (key signature of G). And the A could be flat or sharp, which won't equate to any of the standard major or minor keys. So now we can guess it uses one of four scales - I'll start each one from A:

1. Ab-B-C-D-E-F-G
2. Ab-B-C-D-E-F#-G
3. A-B-C-D-E-F-G
4. A-B-C-D-E-F#-G

Only two of those (#3 and 4) equate to major/minor keys - #3 is the key of C or Am, and #4 is the key of G or Em.

I could get into modality and all that, but I'll spare you :)

The reason I think it's in G is that a plagal cadence (C-G) is pretty common, and that would make the Em the vi chord - also very common. And in that case, your other common chords would be Am, Bm, and D7.

Guitar teacher offering lessons in Plainfield IL


   
ReplyQuote
(@fretsource)
Prominent Member
Joined: 18 years ago
Posts: 973
 

From what you've got so far, I'd also go for G as the more likely key. But the fact that there's no V7 - I progression present in either C or G gives you an opportunity to establish either of those keys depending on what you do next. It would be quite easy to make C the key if you include the chords F & G7 in the follow-up chords, whereas D7 would more or less ensure that everyone hears G as the chord of resolution.
It wouldn't be so easy to make Em the key, though, as you've already established quite a 'major' feel to your song.


   
ReplyQuote
(@minotaur)
Noble Member
Joined: 16 years ago
Posts: 1089
 

True, G could be a likely candidate. I stand enlightened. :) I thought of C because there are no sharps, suggesting he could use F, Dm, Am or B if he wanted to. Could be a coin toss.

It is difficult to answer when one does not understand the question.


   
ReplyQuote
 Crow
(@crow)
Honorable Member
Joined: 14 years ago
Posts: 549
 

That inverted G chord gives the G-C motion added V-I power, for what it's worth -- the "ti-do" bassline could carry a lot of weight. Yet the move back to G counters that.

Still plenty of room to establish the progression in E minor or C, or elsewhere. Sit on a chord long enough, and you're in that key. :) Bassline motion however can have strong implications for key center as well.

I recommend sitting in a quiet room and playing through what you've got, slowly & repeatedly, until the key becomes clear in your imagination or until you're sick of it, whichever comes first.

"You can't write a chord ugly enough to say what you want to say sometimes, so you have to rely on a giraffe filled with whipped cream." - Frank Zappa


   
ReplyQuote
(@noteboat)
Illustrious Member
Joined: 21 years ago
Posts: 4921
 

That inverted G chord gives the G-C motion added V-I power, for what it's worth -- the "ti-do" bassline could carry a lot of weight. Yet the move back to G counters that.

Or completes it - we have no idea what the duration of the chords are, and a mi-fa-do bassline is perfectly plausible.

Guitar teacher offering lessons in Plainfield IL


   
ReplyQuote
 Crow
(@crow)
Honorable Member
Joined: 14 years ago
Posts: 549
 

That inverted G chord gives the G-C motion added V-I power, for what it's worth -- the "ti-do" bassline could carry a lot of weight. Yet the move back to G counters that.

Or completes it - we have no idea what the duration of the chords are, and a mi-fa-do bassline is perfectly plausible.

Of course. At that point in the somg, presumably it's not cadential motion or key-definitive in either case. Lacking a more complete chart, we don't know much. Bassline could carry a lot of weight, but no more than chord duration -- probably less. They are factors, two among many.

This seems more about composition than theory per se. There is value cor a composer in knowing tonal theory, harmony & form, as it can tell you something about how your note/chord choices will affect how listeners perceive the piece -- but composers cannot be bound by theory. And I recommend our composer spend some good time with his chord progressxions & see what they tell him about the direction of the piece.

"You can't write a chord ugly enough to say what you want to say sometimes, so you have to rely on a giraffe filled with whipped cream." - Frank Zappa


   
ReplyQuote
(@humblefly)
Active Member
Joined: 14 years ago
Posts: 6
 

Melody could have a hand in the key as well. If the melody line (let's say a vocal line) contains an F# note it, the total key could lean more towards the key of G.


   
ReplyQuote
(@macca)
Active Member
Joined: 22 years ago
Posts: 5
Topic starter  

Some great replies there. Thanks very much.

I've played around with it a bit and have added a change, which is G A5 Em. So I guess it's G. But given that Ive used A and not Am, does that change things? Does that mean the A5 is "out of key"?

- Rugby League - The Greatest Team Sport on Earth. You just don't know it yet.
http://www.amnrl.com


   
ReplyQuote
(@greybeard)
Illustrious Member
Joined: 21 years ago
Posts: 5840
 

Does that mean the A5 is "out of key"?
A5 consists of I-V, so it is neutral, as it is the iii that gives a chord its quality as, either, major or minor. It would be out of key if you were playing in Bb, as A would be a diminished chord.
G - B - D
A - - - E
E - G - B

I started with nothing - and I've still got most of it left.
Did you know that the word "gullible" is not in any dictionary?
Greybeard's Pages
My Articles & Reviews on GN


   
ReplyQuote
 Crow
(@crow)
Honorable Member
Joined: 14 years ago
Posts: 549
 

That A5, in other words, is "in key" in G OR C. Still plenty of room to establish a key center -- and no need to hurry. To delay resolution can create tension, which can be effective. Think of "Lowdown" by Boz Skaggs. You don't get a convincing resolution to a I chord until the little horn break. (We can quibble over analysis of anything, but that's how I hear it.) Compositionally, there can be great beauty in ambiguity. Just be aware it's there.

"You can't write a chord ugly enough to say what you want to say sometimes, so you have to rely on a giraffe filled with whipped cream." - Frank Zappa


   
ReplyQuote