# Pure Theory. Part 5

Sorry it took so long, but here it is! And next week I'll talk about modulations and borrowed chords.

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Section 1 - Melodies Click on and read the first couple lessons:
• Lesson 01
• Lesson 02 Section 2 - Seventh Chords Let's take a C major triad and stack another 3rd on top of it (review "stacking thirds" from part 2). The highest note of the triad is G, the 5th note. If we add a minor third to that, we get Bb, which is the b7 of C. Add Bb to a C major triad and you get a "C dominant 7 chord" or simply "C7." If we added a major 3rd to the G instead we would have B, and the chord would be "Cmajor7." So C-E-G-Bb is C7 and C-E-G-B is C major 7. Here are the formulas for 7th chords: 1-3-5-7 Major7 1-3-#5-7 Augmented Major7 1-3-5-b7 Dominant7 1-3-#5-b7 Augmented7 1-3-b5-b7 Dominant7(b5) 1-b3-4-b7 Minor7 1-b3-5-7 Minor/Major7 or minor-major7 or minor(major7) 1-b3-b5-b7 Half-diminished 1-b3-b5-bb7(or 6) Diminished7 or "fully-diminished" 7 Now let's figure out how 7th chords work in diatonic harmony. Recall that diatonic harmony involves using only the notes available in a given diatonic scale. So let's harmonize the G major scale into 7th chords: GBDF#-ACEG-BDF#A-CEGB-DF#AC-EGBD-F#ACE So we end up with this formula for 7th chords in major scales: IM7-iim7-iiim7-IVM7-V7-vim7-vii0/7 (Usually to notate a half-diminished7 you'll see a little o in the upper right corner with a / through it, since I can't type that on my keyboard I used the notation you see above) So the I and IV chords are major7ths, the ii, iii, and vi are minor7ths, the V is a dominant7, and the vii is a half-diminished7. Section 3 -Extensions By stacking more thirds you get 9th chords, 11th chords, and then 13 chords, but usually we don't use "block voicing" in real music. A block voicing is an 11th or 13th chord that includes every note (So a 13th chord that includes the 9th and 11th note for example). Usually notes are "omitted." Let's use a Cmajor13 chord CEGBDFA The important note is the 13, so we keep it or it isn't a 13th chord. The 11th and 9th are extensions we can get rid of easily. The 7th depends on your taste - Some jazz players consider the 7th to always be an essential note, while some classical composers consider it an extension just like 9, 11, or 13. The 5th can also be omitted because, unless it's a b5 or #5, 5s don't really change the sound of the chord, they only make it sound thicker. A great way to handle extensions is "add harmony" which is when you add the extension of your choice to the triad, not concerning yourself with tertian (stacking 3rd) harmony much at all. 9ths, 11s, and 13s can each be flattened or sharped, just like any other note, for a different sound. They are often used to emphasize melodic notes. For example, if the chord progression is C, F, G, and the melody is C-G-A, F-A-C, G-D-E, you might want to include the 13ths in the C major and G major (A and E) because they are in the melody. Next week I'll talk about modulations and borrowed chords.
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just wanted to give you some key board shortcuts for diminished and half diminished symbols ALT 0176 will make for diminished and ALT 0428 will make this for half diminished, it's not perfect but it works.... any ways this is a pretty good lesson, keep up the good work!
@kryptic, that are awesome shortcuts. Do you have some table of corresponding codes and keyboard shortcuts?
Thanks krypticguitar87, I'll use those from now on!
unfortuantely no, I think I found those by googleing it.... but I memorized the sign and the other I have wrtten in my phone cuz I don't use it as often but like to have it when I need it also made a typo and it should be ALT 0248 for Alt 0428 will give you this