Sharps & Flats in the same key

[LaughingSkull]

I was taught that sharps and flats shall not be present in the same key. Then I encounter G melodic minor:
G A Bb C D E F#

So Bb and F# in same key. What am I missing?
Or is it the concept : G minor is a key and G melodic minor is ... hmm.

[Malcolm]

Yes I grew up with:
No sharps and flats in the same scale.
No repeated numbers in the same scale.
..... and there is one more rule I can not think of right now.

However, the exotics mix them quite often.
http://www.looknohands.com/chordhous.../index_rb.html
The blues scale:
1, b3, 4, #4, 5, b7 or 1 b3, 4, b5, 5, b7 Got you either way.

Back to if it sounds good do it?

[Jed]

The melodic minors add sharps (via the raise 6th and 7th of the minor scale) out of the normal sequence of addition of sharps (FCGDAEB). I tend to think of the Melodic Minor as the natural minor scale major-ized by the raised 6th and 7th. Melodic minor = Aeolian with a raised 6th & 7th - or - Melodic Minor = Ionian with a flat 3rd.

G minor (natural) = G A Bb C D Eb F
G Melodic Minor = G A Bb C D E F#
G Major = G A B C D E F#

One thing to remember is that the Melodic Minor (and the Harmonic Minor) are alterations of standard diatonic practices (applied to the natural minor scale) - designed to make the minor keys function more like the major keys (with their major V chord and Major IV chord).

I was taught that sharps and flats shall not be present in the same key. Then I encounter G melodic minor:
G A Bb C D E F#

So Bb and F# in same key. What am I missing?
Or is it the concept : G minor is a key and G melodic minor is ... hmm.

[forgottenking2]

Excellent posts so far. I just came in to maybe explain it from a different angle. Think of the minor key as a tonality with two variable tones the 6th and the 7th. Since we are not playing classical music, the restrictions are gone (we can have a minor V or a leading tone not resolving to tonic, etc). That allows you to freely use all the tones (including those which vary). With that in mind, we can think of a C minor tonality as containing the following notes : C D Eb F G Ab A Bb B. In terms of scale organization and what not you have your harmonic minor and melodic minor along with the natural minor scale but in music, they all belong to the same tonality.

I hope this helps.

-Jorge

[JonR]

The governing rule is actually that there should be one of each note (letter) and only one.
When you operate this rule with major keys, it produces the secondary rule about sharps only in sharp keys, and flats only in flat keys.

In minor keys, however, there are 3 exceptions to the secondary rule:

G melodic minor G A Bb C D E F#
G harmonic minor G A Bb C D Eb F#
D harmonic minor D E F G A Bb C#

- but of course they still obey the primary rule

[Jed]

The governing rule is actually that there should be one of each note (letter) and only one.
When you operate this rule with major keys, it produces the secondary rule about sharps only in sharp keys, and flats only in flat keys.

Agreed. One comment - In music theory there are only two rules (IMO) that govern (7-note) major scale construction and the determination of "proper" note names:

1) Each letter is used once and only once in any particular scale
2) The intervalic sequence, starting from the root and continuing between adjacent degrees is - wwhwwwh

The fact that this results in there being no natural major scale (and hence no natural mode) that has both sharps and flats - is an effect of the two governing rules. Again, this is an effect of the rules, not a rule in it's own right.

Minor keys (which are a composite of the Natural, Harmonic and Melodic minors) do not fall within the scope of the rules governing "7-note major scale construction" (even though minor keys were originally based on the natural minor) because of the govering rules for harmonic and melodic minor scale modifications (raising of the 6th and/or 7th on the minor scale). It is the conversion from natural minor to Harmonic or Melodic minor that breaks out of the standard "major scale construction" methodology.

cheers,

[gennation]

I was taught that sharps and flats shall not be present in the same key. Then I encounter G melodic minor:
G A Bb C D E F#

So Bb and F# in same key. What am I missing?
Or is it the concept : G minor is a key and G melodic minor is ... hmm.

Seems like maybe you're confusing Key Signatures with Scales. Key Signatures are based on either #'s or b's, but scales are not Key Signatures. Scales other than the Diatonic Major scale can have any grouping of #'s and b's.

Scales are an organization of notes that create a certain sound. Key Signature help you manage the Major and Minor Keys. Also, ANY Key can have accidentals, this doesn't change the Key Signature.

So, where G minor is a Key, G Melodic Minor is a Scale.

[LaughingSkull]

Great posts guy. Very enlightning. Thanks.

[wild_child]

Seems like maybe you're confusing Key Signatures with Scales. Key Signatures are based on either #'s or b's, but scales are not Key Signatures. Scales other than the Diatonic Major scale can have any grouping of #'s and b's.

Scales are an organization of notes that create a certain sound. Key Signature help you manage the Major and Minor Keys. Also, ANY Key can have accidentals, this doesn't change the Key Signature.

So, where G minor is a Key, G Melodic Minor is a Scale.

So what if the piece featured raised 6ths and 7ths without exception? I understand that the key signature would still read G minor, but would the key not be G melodic minor?

[gennation]

So what if the piece featured raised 6ths and 7ths without exception? I understand that the key signature would still read G minor, but would the key not be G melodic minor?

There's no "Key of G Melodic Minor". Keys are Major or Minor. THe Circle of 5th's is available to provide you/us with the available/appropriate Key names.

[Joe Pass Jr]

They key would still be represented as minor or major on the chart, for ease of reading. You can treat it as a 'melodic minor' key though if you see fit. I often do when improvising some tunes. Its a bit backward to think of it that way though.

[wild_child]

I guess that makes sense when applied to music in the real world. Although I've always read a key signature as a general trend of the piece in order to notate as few accidentals as possible, rather than a concrete name for the key at any given time.

My example was a hypothetical one, but in that particular case, I don't see the point in thinking of a piece in such ambiguous terms when the minor key is without exception, melodic minor.

I suppose I think of 'key signature' and 'key' as two different things, the latter more specific than the former. Or maybe I am just backward.

[JonR]

I guess that makes sense when applied to music in the real world. Although I've always read a key signature as a general trend of the piece in order to notate as few accidentals as possible, rather than a concrete name for the key at any given time.

My example was a hypothetical one, but in that particular case, I don't see the point in thinking of a piece in such ambiguous terms when the minor key is without exception, melodic minor.

I suppose I think of 'key signature' and 'key' as two different things, the latter more specific than the former. Or maybe I am just backward.

I doubt you would ever find a piece written entirely in melodic minor. It just doesn't happen.
The concept of the "minor key" is based on the natural minor scale, and the 7th - and less often the 6th - is occasionally raised at cadences, or for other specific melodic affects. Conventionally, the melodic minor scale (and its harmonised chords) is considered too close to major to be of much use, beyond that occasional strengthening of cadences.

But you're right that key signature and key are two different things.

"Key" refers to a tonality based either on the major scale or the natural minor (the latter with occasional alterations). It's distinguished from other tonalities (such as modes) by its strong sense of forward movement and cadence - "functional" harmonic "progressions" towards a "tonic".
It's identified by its tonic and its quality (eg "D major" or "C minor").

A "key signature", OTOH, is a notational shorthand specifying a standard set of 7 notes (which ones are altered from the 7 natural notes) to be used in a specific piece of music, not a key as such. IOW, no tonic note is specified.
That set of 7 notes (the same key sig) could be used for at least two keys: major and relative minor. It could also be used (in theory at least) for the other 5 modes of that scale.
In any one of those 7 cases, accidentals might be used for alterations from the key sig specification. It just happens that certain standard alterations occur in minor keys. (Just not often enough to make it into the key sig.)
The most common use of any key sig is for the relative major key, which is why we tend to associate them in that way. Eg we call 2 sharps a "D major key sig" (even tho it could be B minor almost as often).

Of course, you can specify any key sig you want, any combination of sharps and flats, if you want to indicate an unusual set of notes to be used more or less throughout a piece (such as G melodic minor). It would be unconventional - and you'd get raised eyebrows among any musician you gave it to - but perfectly OK. (As long as you don't mind having to explain yourself to your musicians, that no it's not a mistake ... )

[Malcolm]

I suppose I think of 'key signature' and 'key' as two different things, the latter more specific than the former. Or maybe I am just backward.

The most common use of any key sig is for the relative major key, which is why we tend to associate them in that way. Eg we call 2 sharps a "D major key sig" (even tho it could be B minor almost as often).

I tend to think in general terms. Key to me is a range of sound . That range is identified by the notes within that range - thus the scale they come from. That scale happens to have a certain number of sharps and or flats. The number of sharps or flats is then shown in the Key Signature as a musical notation that quickly tells me what scale will be used in this piece of music, i.e. the old guys decided to use #'s and b's instead of saying G or F.

That gets me to the starting place. If I then want to branch off into Relative, melodic or harmonic minor or a Mode or a pentatonic scale or whatever I can. The Key Signature just identified the basic starting place.

But, like I said I tend to think generally. Key is a range of sound and Key signature identifies with #'s or b's what that specific sound is named.

I do use the word Key for example; "The chords in the key.", but would use the word scale instead of key when saying; "The notes in the scale." , i.e. Chords and Key together and then Notes and Scale together. We do tend to have our own pet meaning for the word Key.

[leegordo]

ok! hereit is once again to all those out there, when you are reading advice from an official book or instructional manual, please very carefully re- read every thing which puzzles you. The information you read about sharps and flats 'NOT' appearing in THE SAME PIECE OF MUSIC refers not to a piece of music, but to the Key SIGNATURES ONLY of pieces of music, for instance a piece of music written in Key A,will have 3 sharps written at the beginning of every stave of music It is called the Key Signature