Diatonic Scale Construction

[usb_chord]

Hi, everyone. I'm practicing constructing diatonic scales and I'm having trouble understanding the concept of the double flat/sharp.

It is just used for "forcing" the musical alphabet to remain in alphabetical order when the scale is written?


The intervals for the diatonic scale are W-W-H-W-W-W-H so, with that information applied to the chromatic scale, the A# diatonic scale (for instance) is apparently understood to be: A# B# C## D## E# F## G## A#

That is truly a headache to look at and think about! Is it "wrong" to express the A# diatonic as: A# C D D# F G A A# ? I'm sure that's blasphemous to the music theory gods but I couldnt help but ask.

Also, are there double flat/sharp diatonic scales as well? If so, why would that even be necessary??

Thanks a bunch, everyone.

[vac4873]

Originally Posted by usb_chord

It is just used for "forcing" the musical alphabet to remain in alphabetical order when the scale is written?

Yes. That is absolutely the reason, no other. Things would get pretty confusing if the C# scale had both C and C# in it, hence the B#. There are only 15 "official" major scales - C major with no sharps or flats, G-1sharp, D-2, A-3, E-4, B-5, F#-6, and C#-7. F major has 1 flat, Bb-2, Eb-3, Ab-4, Db-5, Gb-6, and Cb -7. Because there are no key signatures with more than one sharp or flat on any line or space, The spellings that would include double sharps are omitted, (D#, G#, and A#) and their enharmonic (sound the same but spelled differently) keys are used. Double sharps and flats come in handy, however, when you are creating a chord that requires altering one of the pitches (for example, a minor chord is created by "flatting" the third scale degree - so Gb minor would be spelled Gb, Bbb, Db).

Hope this helps

Matt

[Americanelson]

A#? Unless I am missing something, this should be Bb - which is Bb, C, D, Eb, F, G, A. Forget A# unless it is an academic excercise.

[ljguitar]

Originally Posted by usb_chord

Hi, everyone. I'm practicing constructing diatonic scales and I'm having trouble understanding the concept of the double flat/sharp.

Hi uc...
From a practical standpoing - double flats or sharps are only theoretical (or mathematically possible).

Our instruments are mostly compensated, and rather than drive yourself nuts, just stay with the keys which are common (unless you like being driven nuts and living in a realm that even most other gutiarists will underappreciate).

If you are an eclectic composer carving out your niche by being unusual then perhaps it would be a viable avenue, but in 46 years of guitaring, I've never been asked to write, arrange, or accompany in double flats or sharps yet...

[815C]

As has been posted above, you should never run into a double sharp when working with major scales.

However, you will run into them if in some of the harmonic minor scales...

G# Harmonic Minor
G# A# B C# D# E F## G#

D# Harmonic Minor
D# E# F# G# A# B C## D#

A# Harmonic Minor
A# B# C# D# E# F# G## A#

[usb_chord]

Thanks a bunch, everyone - this helps a ton. I'm reading an ebook on Chord-Melody style guitar, and it asked me to practice writing diatonic scales. My only other concern is the possibility of a double flatted "key" (assuming "key" = the first note of the diatonic scale) One of the scales it told me I should've came up with is: C## D## E## F## G## A## B## C

Could this be a typo? I have no idea how I was supposed to come up with this.
It's the only "double sharp" key they have in the list of possible diatonic scales.

For the curious, heres a link to the book: http://www.scribd.com/doc/12360067/L...dByColinSobers

[mmmaak]

[Bryan T]

Originally Posted by usb_chord

That is truly a headache to look at and think about! Is it "wrong" to express the A# diatonic as: A# C D D# F G A A# ? I'm sure that's blasphemous to the music theory gods but I couldnt help but ask.

One of the traits that music theorists like for a seven note scale to have is for each note to have its own unique name. In other words, they'd like for you to only have one type of A, one type of B, one type of C, one type of D, etc. Towards that end, your spelling of the A# scale in incorrect.

As others mentioned, in practice scales with more than six sharps or flats (requiring double sharps or flats) are more commonly written with flats or sharps.

I'd suggest looking at the circle of fifths, as it will clue you in to which scale roots are 'sharp keys' and which are 'flat keys.' As others mentioned, the key of A# is more commonly seen as Bb, which is a lot easier to read (only two flats to worry about).

Bryan

[Howard Klepper]

Tnevermind

[johnnyTakam]

Well, it's something to go deeper, but don't get stuck in that math discussion, it's just a matter of sound. I mean, leave those concepts when you're away from the guitar. Otherwise you will be confused while playing

[ljguitar]

Originally Posted by johnnyTakam

...don't get stuck in that math discussion, it's just a matter of sound...

Hi johnny...
Yes, it is primarily a matter of sound...music when only defined or written on paper, or in discussions without an instrument in hand, is as useless as a snooze button on a smoke alarm...

[Ryler]

Good one, Larry!