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Keys, chords, solos

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incognito167
(@incognito167)
Estimable Member
Joined: 18 years ago
Posts: 110
Topic starter  

Sorry for the long post, but i need your help. :?

I need to get my head around this, so i'm going to explain what i already know (so that you can tell me if i am correct or not) and then ask some questions too. Right here goes!

If a song in an a particular key then this means that the notes used are from that particular scale (disregarding accidental) and that the chords used are derived from the notes in that scale too.

So if the Key is C (C major) then the notes used are C,D,E,F,G,A,B and the chords are C, Dm, Em, F, G, Am, Bdim. Am i right so far?

So it follow that if the key were Cm or G#major or anything else then the notes used are from its corresponding scale and the chords are major,minor, minor, major, major, minor, diminished.

So how do you work backwards? Say someone gives you a set of chords and says what is the key, how do you work it out? Is it just because you've learned all of your key/chord tables of is there a way of working it out?

Once you know what the key is, how do you know what scales you can use to solo over a chord pattern from that scale? Using C major again, what scales can you use over this - the C major scale, the C major pentatonic i assume as they contain the same notes. But what about minor pentatonics - do you use C mnor pentatonic or the A minor pent because the Am also has the same notes but a different tonal centre (something else i don't really understand!) Where do modes fit in?

Summary - so my questions are these...
The key refers to the notes and chords used in a song. Is this correct?
How do you work out the key if given a bunch of notes or a bunch of chords?
When you know the key, which scales can be used over it?

Again sorry for the lengthy post, but i need to get my head around this for me to progress.

Thanks.
Mart.


   
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mushin
(@mushin)
Eminent Member
Joined: 18 years ago
Posts: 30
 

Hi Incog,

I dont have many answers for you ( I am but a newbie) but my understanding is that every major scale has a relative minor. So if you are in the Key of C, the relative minor would be based on the 6th note of the scale, ie A. Now from a chord perspective, this would be Am (not Amajor).

The counting then progresses in the pattern from the 6th.
ie

min, dim, maj,min,min,maj,maj.

so in our case:

Am, Bdim, C, Dm, Em, F, G

which happens to be the same as the Key of C major starting at a different point.

To take this to the next regarding which key to play in over which chords, my experience level cant help. This is something we touched on at last weeks lesson, and in broad terms, the scale of the key should sound ok over any of the chords, but some will sound better than others, especially if you start to look into the make up of the said chord. eg- if playing a Cmajor chord, (CEG) then any of these notes will blend well where as others may or may not depending upon the style of music and feel you are generating.

My 2C worth ( and it gave me a chance to clarify my thoughts. thanks)

Mick


   
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Ignar Hillström
(@ignar-hillstrom)
Illustrious Member
Joined: 19 years ago
Posts: 5349
 

Key doesn't help you at all when deciding what scale to use. A jazz in C, a country song in C and a doommetal song in C require quite different scales.

When you have the chords, write them down and try to see which one is most likely the root. For example: C-C-Dm-G could be a I-I-ii-V progression in C or a IV-IV-v-I progression in G. Both are possible, and you'd have to decide for yourself which one is most logical. With the F in the Dm the key of C seems, from paper, most logical.

Minor chord formula:

minor-minor(diminished)-major-minor-minor-majoir-major
Am-Bm-C-Dm-Em-F-G


   
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Alan Green
(@alangreen)
Member
Joined: 20 years ago
Posts: 5342
 

So how do you work backwards? Say someone gives you a set of chords and says what is the key, how do you work it out? Is it just because you've learned all of your key/chord tables of is there a way of working it out?

Not so much a problem as you'd think. I you're given the chords then you extract the individual notes until you've got just the seven notes in the scale and it should be relatively straightforward.

So, you're given the chords A, G, Em, Bm, F#m, D and C#dim

Actually - the C#dim practically gives the answer away, but we'll ignore that for now.

Looking at the individual notes in the triads

A - A, C#, E
G - G, B, D
Em - E, G, B
Bm - B, D, F#
F#m - F#, A, C#
D - D, F#, A
C#dim - C#, E, G

Get rid of all the duplicate notes, and you're left with

A, C#, E, G, B, D, F#

Put them in order so you have one of each note

A, B, C#, D, E, F# G,

Now you need to either kow your key signatures, or the step-halfstep pattern of major and minor scales. It's easier to know that two sharps is D Major or B minor. If you need us to explain how the step-halfstep patterns work, then check out some of the lessons on this site and we'll happily fill in the blanks.

Best,

A :-)

"Be good at what you can do" - Fingerbanger"
I have always felt that it is better to do what is beautiful than what is 'right'" - Eliot Fisk
Wedding music and guitar lessons in Essex. Listen at: http://www.rollmopmusic.co.uk


   
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incognito167
(@incognito167)
Estimable Member
Joined: 18 years ago
Posts: 110
Topic starter  

Thanks for the advice guys.

I'm a little more enlightened but think i need to take a while to really get my head around which solos/keys i should use and where/when to use them.

Mart.


   
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NoteBoat
(@noteboat)
Illustrious Member
Joined: 19 years ago
Posts: 4921
 

The key refers to the notes and chords used in a song. Is this correct?

I can understand your confusion.... the word 'key' means a bunch of different things.

It can mean 'key signature', which identifies the sharps and flats used. In that context, you could look at a piece of music and say "this is in the key of G" - even though it uses the E minor scale and chords.

It can mean the tonic (or root note) of the scale that's used. This can be different from the key signature... G Mixolydian has G as the tonic, but the key signature will be C.

When you're talking about chord progressions, the 'key' is the I chord (or i chord)... which typically follows a V7. So you could have a key signature of A - three sharps - with a chord progression of F#m-Bm-C#7. You'd say that was a i-iv-V progression in the key of F#m.

The chord progression will usually match the tonic of the scale used... but being in the key of F#m with your chord progression doesn't mean you must be using the F#m scale.

So "Key" isn't really precise, although it certainly narrows things down. It's like saying I live in the city; you know I probably don't live on a farm, but I might live in NY, LA, or some other place.
How do you work out the key if given a bunch of notes or a bunch of chords?
Alan's method is very useful in figuring out what the key signature is, so that's a good start. Once you've done that, look for the seventh chords - and what follows them. Sevenths followed by a major or minor chord is often a V-I (or V-i) change... it's called the authentic cadence. If all the 7ths are followed by the same root - that is, if G7 is always followed by C or Cm (or Cmaj9 or Cm7 or any other major or minor type), then you're probably in a "C" key.

Figuring out whether it's C major or minor is often really easy - the chord following the 7th will be major or minor all the time. Some keys use variations called 'borrowing from the parallel key' though, so a double-check is to compare it to the key signature. If your C chord types have a key signature with 3 flats, you're in C minor; if there aren't any accidentals you're in C major.
When you know the key, which scales can be used over it?
The general rule of thumb is that the tonic of the scale and the root of the tonic chord are the same note. There are exceptions, but not many - especially in popular music.

So if you've decided the key is C minor, you will have some kind of C scale. The most obvious choice will be one of the C minor scales - the natural, harmonic, or melodic minor - but you've got lots of other choices. You could work with any C scale (even the C major!) and make it work if you choose the notes carefully. Most people won't want the thirds to clash, so other fine choices might be the Dorian, Phrygian, gypsy minor, mixed minor... you're only limited by your ability to create a melody that sounds good with the chords.

Guitar teacher offering lessons in Plainfield IL


   
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incognito167
(@incognito167)
Estimable Member
Joined: 18 years ago
Posts: 110
Topic starter  

Once again Noteboat you've really helped me out.

I'm due to get your book at the end of this month (that's when i get some student loan!) so i don't yet know how much detail it goes into. But having said that, i'm sure with you could write another book with all of the detailed, yet clear and concise, advice you give. You wouldn't even need to physically write another book, just put all of your posts on these forums into order and you'll have a compendium of musical knowledge!

I'll have to re-read you post a few time to really get my head around it, but it really has cleared things up.

Thanks.
Mart.


   
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