Simple(?) Theory related Question

[BoksteR]

I`m just starting to get into the principles of musical theory.

My status:
-If I know what scale is playing, I can improvise in it.
-With a pen and a piece of paper I can find out the chords of a specific scale.

My question:
How do I know what scale is it if I know the chords?
Lets say, I've got a chord progression of Em,C,B,B.

10nX

[nuffink]

My question:
How do I know what scale is it if I know the chords?
Lets say, I've got a chord progression of Em,C,B,B.

10nX

Do you mean what Key is it?

[Amberience]

I'm not totally sure on this. I think you do it by a method of deduction. Do you know that with major keys you get this interval structure (with the corresponding chord types):

I = Maj (tonic)
II = Min
III = Min
IV = Maj (Perfect fourth)
V = Maj (Perfect Fifth)
VI = Min
VII = Dim

The trick is to find out where your chords go.

Eminor we know could be II or VI, because its minor. The other two are major, so they are going to be the root, or fourth, or fifth.

Although this only works for major scales, and my theory knowledge is limited anyways, so I could be talking out my arse.

[selfconstruct]

A chord is a voicing of a scale in the beebop approach, so the question is valid. If jazz is where you are headed, it would be worth checking out this http://www.outsideshore.com/primer/primer/index.html

[nuffink]

A chord is a voicing of a scale in the beebop approach, so the question is valid. If jazz is where you are headed, it would be worth checking out this http://www.outsideshore.com/primer/primer/index.html

True, you could call a chord a voicing of a scale. However, he's asking about a chord progression which probably means he's asking about a key. No?

Anyway we'll know when he gets back to us.

[BoksteR]

10nx for the answer,
I think my terminology maybe wrong, sorry about that

The answer I would like to get is something like this:
If you play X,Y,Z chords you then you can improvise on the X minor scale [fill in the blanks]...

[Amberience]

Well then you want to turn your chords into a scale - so Em, Cmaj, Bmaj. looking at www.looknohands.com I can see that E melodic minor desc. with a raised 7th fits with your chords.

E F# G A B C D#

[Amberience]

Basically the chords usually come from a scale, so if you want to fit a scale to a set of chords you've come up with, you analyse the notes in those chords and make a scale.

[JumpingJackFlash]

The easiest way to do this is to look at the end of the piece, or the end of a secion in the piece (end of chorus and/or the end of the verse).

The ending chord will usually be the root chord, ie, the piece ends on the tonic. This means, that often (but not always), the ending chord is the same as the key you're in. (Eg, if the ending chord is Cmaj, the key is also C major.)

A good check, is to look at the chord imediately before the last one. Often this is the dominant; the 5th chord in the scale. - Most pieces end with V-I, dominant-tonic. Eg, Gmaj to Cmaj in C major.

Also, the starting chord of the piece or section is often the tonic also.

Another way, is to look at the key signatuire at the start of the piece, and/orthe acsidentals in the piece. - Look for any notes that are sharpened (#) or flattened (b). Then, look up what scales use those notes, and that's your key.
Eg, no sharps or flats = C Major
Just F sharp = G major
F sharp and C sharp = D major
B flat = F Major. etc.

This only works providing the piece in question follows a set key of course. If the piece os A-tonal (no key), then you won't be abal to identify one.

Hope this helps.

[Barnadine]

Your brain may work differently, but the simplest practical answer is to follow any melody through to its root note, the note on which a melody comes naturally to rest. If you're not doing weird exciting things with tonality, that root note will lead you to your key. Determining major from minor shouldn't be a big hassle.

edit - Mr Flash got there before me.

[Amberience]

Sounds to me as if he doesn't have a piece of music, rather he's trying to create one.

[the_nihilist]

Well then you want to turn your chords into a scale - so Em, Cmaj, Bmaj. looking at www.looknohands.com I can see that E melodic minor desc. with a raised 7th fits with your chords.

E F# G A B C D#

Also known as Harmonic Minor.

[Jbravo]

if you're composing a piece in Eminor then those chords would be conventional and I expect that's the key you're thinking of, but they could be chords used in several other keys for a more unusual experimental sound - it really depends on the whole context of the piece to say for sure what key it's in. Like the others say, find the chord in which the piece sounds completely resolved (often at the beginning or the end) and that chord basically describes the key - ie. if the chord is E G B then the piece is in E minor

[Amberience]

Well then you want to turn your chords into a scale - so Em, Cmaj, Bmaj. looking at www.looknohands.com I can see that E melodic minor desc. with a raised 7th fits with your chords.

E F# G A B C D#

Also known as Harmonic Minor.

Yeah but the way I said it made me look like I knew what I was doing

[BoksteR]

10nX