Please explain Keys (in simple terms)

Rocker

I am familiar with playing in different keys. I understand the practice but am blank on the theory or the reasons why.

For example a song in the key of G would have some or all of these chords: G, C, D, A minor, B minor, E minor. Those chords sound 'right' - the same with equivalent chords in different keys - but I can't get an understanding why, the chord E minor for example, works so well whereas F minor is unlikely to work in that key [G major].

My technical and theory knowledge is minimal so any help or guidance, in showing me the whys of chords and their relationship with each other, will be very much appreciated. Thanks

stickyfiddle

To put it simply, those chords work because they only contain notes that are in the scale of your key. 

So in G major your scale goes G A B C D E F#. So, generally speaking, any chord that contains those will sound "right" within that key. 

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

etc

Jalapeno

Only chord you are missing is the 7th - f#m7b5 also seen as f#Ø, known as the half-diminished.

viz

stickyfiddle said:

To put it simply, those chords work because they only contain notes that are in the scale of your key. 

So in G major your scale goes G A B C D E F#. So, generally speaking, any chord that contains those will sound "right" within that key. 

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

etc

Sneaky edit: you mean D major obviously

Rocker

"those chords work because they only contain notes that are in the scale of your key"

That is the answer to my question and the solution to the great mystery of why some chords work and others don't.  Thanks guys.

Lestratcaster

When you harmonise a scale in chords you must follow the formula

Major Minor Minor Major Major Minor Diminished

Then you know what chord types follow the Tone Tone Semi-Tone Tone Tone Tone Semi-Tone order.

E.g

C D E F G A B is the C major scale using the T-T-ST-T-T-T-ST formula.

So in chords its:

Cmajor Dminor Eminor Fmajor Gmajor Aminor Bdiminished.

Rocker

Thanks @Lestratcaster.  My friend and fellow guitarist in my band worked out that much by ear in the early 1970s.  Well everything apart from the diminished chord.  And I don't remember ever including a diminished chord.  That is what I meant by understanding keys and chords in practice.  At IGF 2000, Lee Hodgson explained about the T-T-ST etc. which explained what we had worked out.  We just memorized every chord that worked in every key as you wrote above.  Seventh chords often worked as link chords; G major - G seventh - C major.  My understanding of why these chords worked is just about nil.  I knew that they worked.

Jalapeno

Lestratcaster said:

When you harmonise a scale in chords you must follow the formula

Major Minor Minor Major Major Minor Diminished

Then you know what chord types follow the Tone Tone Semi-Tone Tone Tone Tone Semi-Tone order.

E.g

C D E F G A B is the C major scale using the T-T-ST-T-T-T-ST formula.

So in chords its:

Cmajor Dminor Eminor Fmajor Gmajor Aminor Bdiminished.

For 3 note chords (or triads) you are correct, when the 7th is played it changes

MAJ min min MAJ DOMINANT7 min half-diminished

Lestratcaster

Jalapeno said:

Lestratcaster said:

When you harmonise a scale in chords you must follow the formula

Major Minor Minor Major Major Minor Diminished

Then you know what chord types follow the Tone Tone Semi-Tone Tone Tone Tone Semi-Tone order.

E.g

C D E F G A B is the C major scale using the T-T-ST-T-T-T-ST formula.

So in chords its:

Cmajor Dminor Eminor Fmajor Gmajor Aminor Bdiminished.

For 3 note chords (or triads) you are correct, when the 7th is played it changes

MAJ min min MAJ DOMINANT7 min half-diminished

I'm aware of that. I was just using triads as the most basic form.

Didn't do 4 years at ACM for nothing lol.

sm55onl

stickyfiddle said:

...

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

....

D F# A....should be named D [M...written?]major ?

Phil_aka_Pip

why are keys the way they are?
well, start with the "simplest" scale C major CDEFGABC R1234567R. Please don't ask WHY the simplest scale (ie no sharps or flats) starts on C and not A, it just does. All adjacent natural note names are 2 frets (a whole tone) apart except for the pairs BC and EF which are a semitone apart. So the spacing between adjacent notes is not equal. Things that arise from this include the different triad (and 7th and extended) chord types that you can build on each degree of the scale, and the different modes you get when you build a new scale starting on each note of the original scale.

Take the modes of C. The Ionian is the same as the major scale. The Dorian is a minor mode starting on D. And so on until you get to the Locrian starting on B. Analyse each mode in terns of the intervals from the root, eg Dorian is R2b3456b7. Notice that two of those modes have only one note that makes it different from a major scale. One of them is the 4th mode (in this example starting on F, it has a #4) and the other is the 5th mode (starting on G, it has a b7).

So what tweaks would turn those two modes back into a major scale? In the case of the 4th mode you flatten it's 4th degree (to give in this example a Bb resulting in an F major scale) and in the case of the 5th mode you sharpen its 7th degree (to give in this example an F# resulting in a G major scale).

Repeat for the F & G scales, following the flattening the 4th degree of the 4th mode of F (gets you Bb maj) and the 7th degree of the 5th mode of G (gets you D maj) - keep any sharps or flats previously collected. Go round again taking modes of your new major scales.

Hey presto! The cycles of 4ths and 5ths. Most music books just give you them but don't tell you why they are that way and you won't understand that until you suss how to derive them from first principles (sketched above).

Music reading hint: Key signatures are always written with the flats or sharps written in the same order as you collect them in the cycles of 4ths and 5ths. So in a flat key the last flat in the key sig is always the 4th degree of whatever major scale the key sig is for (so in 3 flats the last one is Ab, count down the scale Ab=4, G=3, F=2, Eb=1). And the last sharp in a sharp key sig is always the 7th degree of whatever major scale the key sig is for (so in 4 sharps the last one is D#, thats the leading note of the  Emaj scale)

Lestratcaster

sm55onl said:

stickyfiddle said:

...

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

....

D F# A....should be named D [M...written?]major ?

D minor has a Flat 3rd so it should be an F instead of an F#.

sm55onl

Lestratcaster said:

sm55onl said:

stickyfiddle said:

...

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

....

D F# A....should be named D [M...written?]major ?

D minor has a Flat 3rd so it should be an F instead of an F#.

But the Original Poster [OP], Rocker, and also Stickyfiddle noted the key of G major....thus the (three-note: Root, third, fifth) chord progression should have D Major chord (D F# A).

However, Stickyfiddle noted D F# A as Dminor ?

viz

Lestratcaster said:

sm55onl said:

stickyfiddle said:

...

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

....

D F# A....should be named D [M...written?]major ?

D minor has a Flat 3rd so it should be an F instead of an F#.

Well, as Sticky was talking about the harmonisation of G major, he meant to write:

D major - D F# A

not:

D minor - D F A. 

Hence sm55onl's correction. 


Edit - sorry, already answered above!

Rocker

Thanks guys. On first read a lot of the above is hard to take in. I will print it out and study it closely. Music really ought to be on the curriculum of schools, especially second level.

Lestratcaster

sm55onl said:

Lestratcaster said:

sm55onl said:

stickyfiddle said:

...

e.g.
A minor - A C E
C major - C E G
D minor - D F# A

....

D F# A....should be named D [M...written?]major ?

D minor has a Flat 3rd so it should be an F instead of an F#.

But the Original Poster [OP], Rocker, and also Stickyfiddle noted the key of G major....thus the (three-note: Root, third, fifth) chord progression should have D Major chord (D F# A).

However, Stickyfiddle noted D F# A as Dminor ?

Should still be major as D is chord V in the key of G major.

sm55onl

Lestratcaster said:

sm55onl said:

Lestratcaster said:

sm55onl said:

stickyfiddle said

Should still be major as D is chord V in the key of G major.

Bangs head against desk....repeatedly ;-)

sm55onl

Rocker said:

Thanks guys. On first read a lot of the above is hard to take in. I will print it out and study it closely. Music really ought to be on the curriculum of schools, especially second level.

Here’s a couple of web-links for ya’...(in order to read)

Note: your initial question stated a major scale; thus with
T-T-ST-T-T-T-ST construction.

So, in the key of G Major:

G (1st, or root note)
A (2nd note)
B (3rd note)
C (4th note)
D (5th note)
E (6th note)
F# (7th note)

we, basically, stack two sets of third intervals...thus achieving chords using the R-3-5 notes of the scale that we are interested in (G Major here).
[refer to 1st web-link]

However, one can go on to stack a further third interval [2nd web-link] - in actual fact the 7th note of the scale - and use chords consisting of R-3-5-7 notes.

Loads of other variations thereafter are possible.

http://musictheorysite.com/major-diatonic-chords/
http://www.jazzguitar.be/blog/jazz-guitar-chord-theory/

sm55onl

danowens

@Rocker ;Theory can be difficult to wrap your head around when you have a lot of information and not a lot of context. By asking simple questions (as you started out here) you can get answers that have context - these invariably lead to other questions but now you have context to help you with the new answers. Questions such as:

Why is it TTSTTTS and not some other combination?
Why is C Major the 'easiest' key?
How does music break these rules and sound good?
What is Diatonic?
What is Chromatic?
How are Major and Minor related?
Where do Modes fit in?

I think if you fully understand the answers to the above questions, you could consider yourself fairly knowledgeable in the world of theory and you'll definitely have enough context to  tackle some really advanced concepts and not think 'huh?'

Freebird

Simply stated, start learning how to build chords from intervals. It's not that difficult once you get your head around it.