Theory Question Regarding Major Chord Construction

[walternewton]

A couple of things, I would change the note names from "X#/Yb" in your scale/interval chart to the sharp or flat note that fits the interval being defined.

For example, the major second interval from E (and the second note of the E major scale) is F# - while Gb is enharmonically equivalent, it is technically the diminished third.

For another example, the minor seventh interval from C is Bb rather than A#, which would (technically) be an augmented sixth.

Similarly, I'd change the flat keys Bb - Eb - Ab - Db to get rid of the sharp equivalents.

Finally, if you're going to include 9ths and 11ths in your chart, you might as well extend it to 13ths (A in the key of C), which (like 9ths and 11ths) you will see in chord definitions.

[XYRN]

Walter and stanron, thank you for your review.

Originally Posted by stanron

Just one or two points, where you list the notes in the scales for instance of G, the seventh note is F# and not Gb. You get this right in your table of notes in chords except for chord IV in Ab and that may well be a typo. Cheers

I'm not sure I understand.
Are you saying that the IV chord in Ab is not: Db-F-Ab

[walternewton]

I think it's actually the IV chord in Db with the typo.

[stanron]

Sorry I misread. In Db you have chord IV as F#/Gb and I assumed this was a typing error.

[XYRN]

Originally Posted by stanron

Sorry I misread. In Db you have chord IV as F#/Gb and I assumed this was a typing error.

Got it! Thanks, that was a typo.

Originally Posted by walternewton

...
Finally, if you're going to include 9ths and 11ths in your chart, you might as well extend it to 13ths (A in the key of C), which (like 9ths and 11ths) you will see in chord definitions.

Veeery interesting! I did that and I see that doing so results in 21 semitones, hmm, many guitars have 21 frets. Is that by design?

Here's the new spreadsheet with my edits, I left both sharps and flats in the Key of C as that key kinda straddles the fence.

New Link

[walternewton]

Originally Posted by XYRN

I see that doing so results in 21 semitones, hmm, many guitars have 21 frets. Is that by design?

No that's a coincidence

Originally Posted by XYRN

I left both sharps and flats in the Key of C as that key kinda straddles the fence.

No, a minor third interval from C is definitely Eb, a minor sixth is definitely Ab, a minor seventh is definitely Bb.

The last 2 rows you added should be Octave + minor/major sixths, not sevenths.

[XYRN]

Re: 6ths vs 7ths, thanks, I goofed on that.

Okay, so I'm revising the Key of C column.
Is the minor 2nd of C called C# or Db? Is there a rule to the nomenclature in the Key of C?

From previous posts I gather that if we're in the Key of C, G, , D, A, E, B or F# we talk about sharps, and in the Keys of F through Gb we refer to accidentals as flats, is that accurate?
(I realize the term "accidentals" can refer to the symbols for natural, sharp or flat but in other uses may refer to deviations from the layout of a key.)

[stanron]

C is the first note or degree so the second has to be some kind of D. A major second is D and a minor second has to be Db. You should check all the keys. Some are right and some are wrong. The only place where you could have #/b alternatives is between the fourth and fifth degree. That could be an augmented fourth or a diminished fifth.

[walternewton]

C-Db is a minor second - note JonPR's post above about the definitions of major and minor - C-C# would be an augmented unison.

As you can see from your chart, the G, D, A, E, B, and F# major scales contain sharp notes (just talking about the scale notes, not the "in between" ones.)

If you tried to write G with a flat you'd end up with G A B C D E Gb - two G's and no F.

Similarly the F, Bb, Eb, Ab, Db, and Gb major scales contain flat notes (again just talking about the notes in the major scales.)

If you tried to write F with a sharp you'd get F G A A# C D E - two A's and no B.

[walternewton]

Now for the "in between" notes, take a look again at what Jon wrote about counting notes and counting semitones...if, for example, G is the root, then any kind of second (major or minor, or more rarely diminished or augmented) must be some kind of "A" (GA), any kind of third must be some kind of "B" (GAB), any kind of fourth must be some kind of "C" (GABC), etc.

So if G is your root, regardless of the fact that G major is a "sharp" key, a minor third interval from G is Bb (G to Bb is 3 semitones, a minor third).

[XYRN]

Ah, something just clicked, thanks to all!

As I've been making the spreadsheet I've only been 'seeing' the 12-semitone chromatic scale and not the 8 note major scale, so the concept of what ought to be flat and sharp hasn't been understood. But now looking at it again it all pops out. Of course the minor of a major interval would share a letter!
And one of the books I have lists the 6th semitone as the tritone but also in parenthesized tiny letters says "Augmented Fourth/Diminished Fifth" and now I understand why.

This is pretty cool, learning the undercarriage of the structure of music that I've always appreciated but had no idea "what was holding the building up", so to speak.

[oldhippiegal]

this is why I, and others here, often say "man, teaching this on a piano keyboard is sooooooooo much easier." Some of what you're "aha"-ing about is just sitting there in black and white notes, shouting its obviousness, but you're obviously getting it with work on your own. Congrats.

[XYRN]

Originally Posted by oldhippiegal

this is why I, and others here, often say "man, teaching this on a piano keyboard is sooooooooo much easier." Some of what you're "aha"-ing about is just sitting there in black and white notes, shouting its obviousness, but you're obviously getting it with work on your own. Congrats.

I bet it is easier on a keyboard. I think I've read that LJGuitar uses a small portable keyboard to help explain theory to his guitar students, alas, I have no access to one.
Plus, I may be going about this the relative 'hard way' but that's truly the way I learn things permanently.
I could look at all the books in the world that have something laid out plain as day but until I take the information in, process it and spit it out in another form (such as my spreadsheet), I wouldn't really get it. Through my reading and re-reading the posts here and my several revisions it's starting to actually make sense in my head.
Rote memory is one thing, but for some things I need to understand the "why", not just the "what".

Here's my latest revision, I think previous links may now be broken, or only lead to this new one. Theory Spreadsheet

Your spreadsheet shows the formula "Min 7th 1-b3-5-7" - that is for mM7 (minor major 7) not m7.
m7 should be 1 b3 5 b7

[XYRN]

Originally Posted by phmike

Your spreadsheet shows the formula "Min 7th 1-b3-5-7" - that is for mM7 (minor major 7) not m7.
m7 should be 1 b3 5 b7

Thank you!