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Re: B sharp?
9/24/2008 9:05 AM
Dags Still (2888) wrote:
All major scales may begin on any note as long as you maintain the Tone, Tone Semitone, Tone, Tone, Tone, Semitone [ t.t.s.t.t.t.s.] pattern. Those spacings between the notes DEFINE a scale as being MAJOR.
In order to do this, it is necessary to use sharps and flats. Whether you use a sharp of flat depends on the fact that you MUST use consecutive letters of the alphabet in creating the scale
So knowing our CHROMATIC scale [from which all the rest are developed] as being
A . A#. B. C. C#. D. D#. E. F. F#. G. G#. A
That our MAJOR scale goes T. T. S. T. T. T. S.
We can make ANY major scale. For example
If we want to make an F major scale [just as a random example]
We write F.G.A.B.C.D.E.F in consecutive letters of the alphabet [and we have one and only one of each] so far so good, but we dont have the correct sequence of tones and semitones. For that we would have to go
F. tone G. tone A. semitone A# tone C tone D tone E semitone F
which would still be incorrect. Why?
Because now there is more than one A and no B. BUT if we rename the A# to Bb, then we finally get the correct F major scale
F. G. A. Bb. C. D. E. F.
With each letter used just once consecutively. Now we add a Bb to the key signature and we have it. The key of F major always has one b
Lets try the A major scale:
Again because its a MAJOR scale we must use the TTSTTTS sequence and each letter once only in order alphabetically.
A.B.C.D.E.F.G.A is one each consecutive but not TTSTTTS, so
A tone B tone C# semitone D tone E tone F# tone G# semitone A
And hooray, we have none twice, so
A major has 3 sharps in its key signature C#, F#, and G#
Had we tried to write A major scale using flats we would have arrived at this
A tone B tone Db semitone D tone E tone Gb tone Ab semitone A
Obviously wrong because wed have no C or F and two As
So this is why for example A major has sharps rather than flats in itand WE NEVER HAVE BOTH # AND b IN A KEY SIGNATURE.
I do hope this helps someone.