I'm presently working on Beethoven 'Happy and Sad.' This is the first piece I have played in C Minor. So, I'm working on playing the scale for it.

Although they key sig indicates that B, E and A are flatted in this key, in my "Complete Book of Scales, Cadences and Arpeggios" the scale shows that the B is natural. It shows a natural sign in the scale.

I have two questions on this. 1) If the key is defined as having those three keys flatted, why would the scale have it natural, and 2) if the scale has the B as natural, when I play the piece, are the Bs that I encounter supposed to be flatted, per the key sig, or would they be natural since that's how the scale for the key is?

I'm confused on this.
thanks!

The scale is indeed C minor but the b natural makes it a harmonic minor as opposed to the natural minor.
There are 3 minor scales Natural, Harmonic and Melodic.

Minor Scale (wikipedia)

The key signature represents the natural minor key.

Real music seldom follows suit. The seventh note is typically sharpened, B natural in C minor, so that the dominant chord built on the fifth, G seventh, G-B-D-F, resolves to the tonic by a semitone to C. This is the harmonic minor and is usually the first form of minor scale learnt at the piano.

The tone and a half between the sixth and seventh in the harmonic minor is very uncomfortable for singing so in the Melodic minor the sixth is also raised when ascending to tonic. When descending the scale the leading note doesn't need to resolve to tonic so the natural minor is used in descent.

So, we start with a major scale and flatten the third. The sixth and seventh can be flattened also but are not always in practise.

In the piece, play the Bs flatted according to the key signature, unless they have a different accidental applied to them in the music. You will probably see a lot of B naturals in the music, but some Bs might remain flatted.

Kbeaumont mentioned the three different minor scales that people often practice. Here is some more detail about them:

The natural minor scale would have the flats exactly as in the key signature: C D Eb F G Ab Bb C.

The harmonic minor scale raises the seventh note (Bb) a half step (to B natural), to reflect the fact that you will often find B natural marked in a C minor key piece: C D Eb F G Ab B C. This is the one you have in your scale book.

There is also a melodic minor scale which raises the sixth and seventh notes, but only going up. Ascending: C D Eb F G A B C. Descending: C Bb Ab G F Eb C (same as the natural minor scale descending). This also is related to something that you might find in your piece, where the sixth note of the minor scale is raised: A natural instead of A flat.

But the scales are just patterns to get used to the notes you'll often find in minor key music. When reading the score, read the score the way you normally would: use the flats from the key signature unless they are altered by accidentals in the music.

Major and minor keys (and scales) are what we have left over from modes, and it would be good to start with exploring this idea of "mode". Play this:
C,C,G,G,A,A,G(pause), F,F,E,E,D,D,C
Of course you have just played the beginning of Twinkle Twinkle Little Star.
Now play this:
A,A,E,E,F,E,E (pause), D,D,C,C,B,B,A
Now you have played Twinkle Twinkle Little Star in a minor key.

Did you notice that the second version sounded "sad", and it had a different flavour to it? Modes create moods. Historically Western music had 6 of them, and then eventually settle down to two: major and minor, which came out of that. Eventually jazz etc. got the other modes back in, but we won't worry about that.

When we learn to identify major and minor KEYS, then we know the minor key has the same key signature as its "relative major" which starts up a minor third, or "three notes up". Example:

A minor .... relative major is C major
C minor .... relative major is Eb major

Compare the notes:
C minor
C D Eb F G Ab Bb C -----
Eb major
---- Eb F G Ab Bb C D Eb

The key signature of Eb major is very handy for C minor, because it lowers (flats) E, A, B, which are the 3rd, 6th, 7th degree notes of C minor.

This is the starting point, and what you've been told is how it's usually presented because it is easy to start with this. There is more to it, as you've found out.

In harmony, we have a very important chord: the V chord or V7 chord. Music gets a feeling of "arriving" through V-I. Now if we take the notes of C minor as we presented them, then V would be G Bb D which is Gm, and I is C Eb G, which is Cm. So we'd get Gm-Cm. This is a weak combination because this is how the notes would move.
Bb ==> C
D ==> Eb
G ==> G

Play Bb ==> C, and then play B ==> C. Which gives you a stronger feeling of wanting to move to C which is our main note in C minor? It should be B, which is only a half step away from C. Try the same thing Gm => C, and G (GBD) => C. You should hear the second as being more convincing.

So to let us have a V-i instead of v-i (Vm-Im), composers will raise the 7th note, from Bb to Bnat, using a natural sign. Thus you get the "harmonic minor":
C,D,Eb,F,G,AB,B(nat),C

Our V chord becomes G,B,D and our cadence becomes
B ==> C
D ==> Eb
G ==> G

..... But now we have a new problem. Play the "harmonic minor" scale. Does it sound odd and "Oriental"? There are 1 1/2 steps from Ab to B nat. So to smooth out that bump we get another scale, where the Ab has also been raised:

C,D,Eb,F,G,A(nat),B(nat),C

This is called the "melodic minor" scale, and we learn to play it differently going up and down, but in real music that isn't always the pattern.

The real conclusion is that in a minor scale, the first 5 notes are fixed (C,D,Eb,F,G), while notes 6 & 7 toggle "as needed". The first 5 notes give us the i chord CEbG which is minor, and plays a major role in setting the "sad, blue" mood of minor scales.

WOW.
I had no idea.
I knew about major and minor but all this other info is completely new to me.

Thank you VERY VERY much for taking the time to type all this in. I feel a major study session coming on.

It will probably take me a while to soak that all in!

Thank you Thank you !!

Great explanations! I'll simply add that when talking about minor scales, the name helps you remember which is which. Start with the natural (naturally). We raise the 7th note for HARMONIC reasons, and we then have to raise the 6th and 7th for MELODIC reasons. And yes, the melodic reason is only for when the notes are going up, so we don't have to do anything to the scale going down, so it's NATURAL again.

Depends on which minor key you are using. There is the Natural Minor Scale, the Harmonic Minor Scale, as well as the Melodic Minor Scale. They are all very similar but have subtle differences, such as the B (in a C-Minor scale). Composers will often switch between them within the same composition to produce different effects. You can read more about the three here.


edit: didn't realize everyone had already answered

That is what I learned to do when playing scales in lessons. However, it has been pointed out to me that in actual music, composers don't necessarily use that rule. I forget in which compositions and composers we saw that but they weren't modern - maybe even Bach on occasion.

I was thinking over the logic of this. I think that if you have an ascending melody and want it to be smooth, you'll also probably want to use a V chord which means you'll want the raised 7th. The you will naturally go for "melodic minor" to make the run sound smooth. Otoh, when descending, you are not moving 7=>1, so there is no reason to raise the 7th, so you'd tend to go for a natural minor. Might this be how that rule got started? (as a loose rule maybe, that later got entrenched in lessons)

Yes, composers like to break the rules a lot of times, even back in the day. I think they do it on purpose just to mess with us sometimes.

Rules in music are more guidelines, nothing is 100% concrete, or else jazz wouldn't exist.