Music Theory Question

[SprintBob]

I am in the process of expanding my knowledge and understanding of music theory/notation by reading "Edly's Music Theory for Practical People" I'm going slow usually taking in 6-10 pages a week and trying to make sure I understand fully what I am reading before moving on. I've run into two (2) points I don't fully understand and thought I might get help from folks on this forum. I'm reading the most recent 3rd edition so I'll reference the pages and chapters on my two questions below:

Question 1

Refer to Chapter 5, Chords: Triads, page 24.

" A triad is a 3 note chord". "If you take the first, third, and fifth note of a major scale and stack them up, you get a major triad."

"Let's make it into a formula: a major chord (triad) = 1,3,5. This definition applies not only to a C chord, but to any major triad".

Example (in the C major scale) - C-E-G is the major triad of that scale. It is also referred to in the book as a major chord.

My question is a result of the reference we guitar players make to the C major chord we play on our fret boards. It is played by fretting the B string on the 1st fret to form a C note, the 2nd fret on the D string to form a E note, and finally the 3rd fret on the A string to form a C note. So our C major chord on the guitar consists of the C-E-C notes being played together.

So my question is how does the C major scale triad/chord referenced in the book and formed by C-E-G (1-3-5) differ from the guitar chord we call C major of C-E-C? C-E-C is not following the 1-3-5 formula stated for a major chord above. It is a 1-3-8 in the C major scale. This is confusing to me.

Question 2

Same chapter as above, page 25, reference "Creating Minor Intervals"

"If you lower the top note of a major interval by a half step, it becomes a minor interval. For example (in the scale of C) C to E is a major third (C-D-E, 1-2-3), so C to Eb is a minor third."

"You can now define the major triad in terms of intervals: a major third from the root to the third, and a minor third from the third to the fifth."

My question is based upon if the major triad/chord of C-E-G is defined as 1-3-5, how is the E-G (3-5) interval within that specific triad considered a minor interval per the definition above?

Any help on the two questions above would be appreciated!

[pieterh]

1. A major or minor chord is made up of a triad of three notes. In the case of C major the notes are C - E - G. When we talk of chords on the guitar these are made up of these notes, though not necessarily in that order. This is why we often talk about inversions (where the C triad starts on the E or G) or voicings (where the combinations of notes include octaves, doubling, certain notes appearing more than others and so on, but will still be made up of Cs, Es and Gs). So the 1-3-8 you mention above is really only 1-3-1(octave) if you think about it.

2. don't confuse a minor interval (which is based on one whole tone and one half tone separating the two notes) with a minor chord. If you think about it, by making the first interval a minor third (and thus the triad a minor chord) the next interval suddenly goes from being a minor interval (half tone plus whole tone) to a major one (with two whole tones).

[Fruitloop]

For the C major chord you play strum/pluck 5 strings, all except the low E giving you the notes C-E-G-C-E.

I'm not sure I understand the second question. E-G is a minor interval but in the context of the C major chord you should be looking at the relationship of C-G which is a fifth. In other words it is made of the major third and perfect fifth intervals.

[Bob Womack]

Another, simpler way to say the answer to question one is that the C chord we use is not made up only of the fretted strings but also the un-fretted but sounded G to form the triad.

Bob

[stanron]

Wow lots of good replies whilst I was typing this,


Question 1

Don't forget you play the open strings as well. In the chord C

╒═╤═╤═╤═╤═╕	
│ │ │ │ 0 │
├─┼─┼─┼─┼─┤
│ │ 0 │ │ │
├─┼─┼─┼─┼─┤
│ 0 │ │ │ │
├─┼─┼─┼─┼─┤
E C E G C E

The notes are E C E G C E.

Starting on the fifth string you have the basic triad C E G. The other notes make strumming easier and the chord sound fuller but they are all either C E or G.

Question 2

The interval between the root and the third (In C the interval between C and E) is what determimes whether a chord is major or minor. If that interval is major then the chord is major. If that interval is minor then the chord is minor.

[SprintBob]

Thank you all! I get it now.

[JonPR]

Originally Posted by SprintBob

Question 2

Same chapter as above, page 25, reference "Creating Minor Intervals"

"If you lower the top note of a major interval by a half step, it becomes a minor interval. For example (in the scale of C) C to E is a major third (C-D-E, 1-2-3), so C to Eb is a minor third."

"You can now define the major triad in terms of intervals: a major third from the root to the third, and a minor third from the third to the fifth."

My question is based upon if the major triad/chord of C-E-G is defined as 1-3-5, how is the E-G (3-5) interval within that specific triad considered a minor interval per the definition above?

Just to echo fruitloop and stanron:
Chords are built from intervals measured from the root, (3rd and 5th notes up) so you can ignore the E-G interval.

Both major and minor chords have a "perfect 5th". It's the 3rd that differentiates them.
"Major" and "minor" simply mean "larger" and smaller" (out of two options).

HALF-STEPS: |  |  |  |  |  |  |  |
   C MAJOR: C  .  .  .  E  .  .  G
   C MINOR: C  .  .  Eb .  .  .  G
            |___________|
             major 3rd
            |________|
             minor 3rd
            |____________________|
                perfect 5th

IOW, you can disregard the intervals between 3rd and 5th (E-G or Eb-G) because they confuse the issue .
Seeing as the 5ths are the same, it's the 3rd that counts.

The 5th becomes important in augmented and diminished chords, which are defined by their altered 5ths:

HALF-STEPS:   |  |  |  |  |  |  |  |  |
C augmented:  C  .  .  .  E  .  .  .  G#
C diminished: C  .  .  Eb .  .  Gb
              |_______________________|
                  augmented 5th
              |_________________|
                 diminished 5th
              |___________|
                major 3rd
              |________|
               minor 3rd

In this case, the name comes from the 5th, because those intervals are more significant than the 3rds. (An augmented chord always has a major 3rd, and a diminished chord always has a minor 3rd.)
Again, the intervals between 3rd and 5th don't count (in building or naming the chord), although they're of interest here because - as you can see - they're the same size as the root-3rd intervals.

[pjroberts]

Jon - Nice diagrams ... refreshing my theory (with everything else) and a picture is def worth a thousand words.

[SprintBob]

This info is so good I am going to cut and paste it into a document, print, and insert it into my notes! Thanks again!

[jeanray1113]

Good stuff, JonPR! I just pasted that into a document too!

[JonPR]

At risk of too much info...... here's how it works for the six basic 7th chords:

HALF-STEPS: |  |  |  |  |  |  |  |  |  |  |  |  |
        C7: C  .  .  .  E  .  .  G  .  .  Bb . (C)
     Cmaj7: C  .  .  .  E  .  .  G  .  .  .  B (C)
       Cm7: C  .  .  Eb .  .  .  G  .  .  Bb . (C)
  Cm(maj7): C  .  .  Eb .  .  .  G  .  .  .  B (C)
            |_____________________________|            
                      minor 7th
            |________________________________|
                      major 7th
.
HALF-STEPS: |  |  |  |  |  |  |  |  |  |  |  |  |
     Cdim7: C  .  .  Eb .  .  Gb .  . Bbb .  . (C)
     Cm7b5: C  .  .  Eb .  .  Gb .  .  .  Bb . (C)
            |__________________________|
                   diminished 7th

1. "C7" is based on the standard major triad ("C"), with the most common 7th added. The "minor 7th" is the smaller one (10 half-steps), and there are 5 of those in the major scale, and only 2 major 7ths. Economy means we give this chord the shortest name. The rarer one can have the longer name
In addition, the chord which most commonly gets a 7th added is the V - "dominant" - chord in the key, which produces the unique combination of major 3rd and minor 7th; hence the term "dominant 7th" for this chord type. (C7 is the dominant 7th chord in the key of F.)

2. When these two 7ths are added to minor triads, again the plain "7" refers to the b7. The "m" still refers to the b3. As you can see, when we want both the lowered 3rd and raised 7th, both have to be named: "m(maj7)".

3. Adding 7ths to a diminished triad is a little different. We still have two choices, but this time it's between a minor 7th and a diminished 7th (9 half-steps, one smaller than minor).
The dim triad with dim7 added is called - simply enough - "dim7". But leaves the issue of what to call the dim triad with b7 added! After all, following our above rules, we might think that "dim7" means "dim triad with 7 (b7) added".
The solution is to look at the latter chord from two other directions. One is to call it a min7 chord, but with a flattened 5th. Hence "m7b5". The other is to count the diminished intervals in the chord:
Diminished 5th + diminished 7th = "full diminished"
Diminished 5th + minor 7th = "half-diminished"

NB: Cdim7 doesn't occur naturally in any common scale, but dim7 chords are found as vii chords in the harmonic minor scale. As such, Cdim7 would more commonly be named as:
B#dim7 (B# D# F# A) = vii in C# minor
D#dim7 (D# F# A C) = vii in E minor
F#dim7 (F# A C Eb) = vii in G minor
Adim7 (A C Eb Gb) = vii in Bb minor
Of course, we can do this because the chord is symmetrical - 3 half-steps between each note. We can just rename all the notes ("enharmonically"). It still sounds like exactly the same chord, but it can work 4 ways. Doesn't matter which note is on the bottom either.
(There are other things to say about dim chords, but that's probably too much already...)

SCALE ORIGINS OF THE ABOVE CHORDS:

C7 = V in F major, or F minor (harmonic or melodic)
Cmaj7 = I in C major, IV in G major
Cm7 = ii in Bb major, vi in Eb major, iii in Ab major
Cm(maj7) = i in C minor (harmonic or melodic)
Cdim7 = vii in Db minor (a key which would more usually be known as C# minor, see above)
Cm7b5 = vii in Db major (more commonly used as ii in Bb minor).

ADDING 7ths TO AUG TRIADS

HALF-STEPS: |  |  |  |  |  |  |  |  |  |  |  |  |
   Cmaj7#5: C  .  .  .  E  .  .  .  G# .  .  B (C)
      C7#5: C  .  .  .  E  .  .  .  G# .  Bb . (C)

These are quite rare.
Cmaj7#5 can be found in A harmonic and melodic minor, but occurs mostly as a passing chord. (Eg the 2nd chord in Stairway to Heaven.)
C7#5 isn't found in any ordinary scale (none goes G#-A-Bb...), but is considered in jazz as an "altered dominant". It would be linked with the wholetone scale, or the altered scale.

[jeanray1113]

Thanks again, JonPR.

[JonPR]

More...

The following charts show the triads and 7th chords harmonised from the C major scale, showing how the irregular scale structure determines the chord type on each step, by producing different sets of intervals:

TRIADS
 Half-steps: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 
Major scale: C     D     E  F     G     A     B  C     D     E  F 
CHORDS:
  I = C      C  .  .  .  E  .  .  G
 ii = Dm           D  .  .  F  .  .  .  A
iii = Em                 E  .  .  G  .  .  .  B
 IV = F                     F  .  .  .  A  .  .  C
  V = G                           G  .  .  .  B  .  .  D
 vi = Am                                A  .  .  C  .  .  .  E
vii = Bdim                                    B  .  .  D  .  .  F
.
7TH CHORDS
 Half-steps: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Major scale: C     D     E  F     G     A     B  C     D     E  F     G     A
CHORDS:
  I = Cmaj7  C  .  .  .  E  .  .  G  .  .  .  B
 ii = Dm7          D  .  .  F  .  .  .  A  .  .  C
iii = Em7                E  .  .  G  .  .  .  B  .  .  D
 IV = Fmaj7                 F  .  .  .  A  .  .  C  .  .  .  E
  V = G7                          G  .  .  .  B  .  .  D  .  .  F
 vi = Am7                               A  .  .  C  .  .  .  E  .  .  G
vii = Bm7b5                                   B  .  .  D  .  .  F  .  .  .  A

So you get three different triad types - maj, min, dim - and four different 7th types - maj7, min7, (dom)7, m7b5 (half-dim).
Ie, the minor triads all end up with a minor 7th (10 half-steps), as does the only dim triad (making the "half-diminished" chord). But two of the major triads (I, IV) get major 7ths (11 half-steps), while the other (V) gets a minor 7th; the latter making the famous "dominant 7th" chord, so-called because "dominant" is the old name for the 5th (V) degree of the scale.

I = tonic
ii = supertonic
iii = mediant
IV = subdominant
V = dominant
vi = submediant
vii = leading tone, or subtonic

If we arrange those in pitch order (highest on top), with the tonic at the centre, the names make a little more sense:

V = dominant
(IV subdominant)
iii = mediant
ii = supertonic
I = tonic
vii = leading tone, or subtonic
vi = submediant
(V dominant)
IV = subdominant

(NB: this doesn't mean that in actual music, the dominant is always the highest note! But it does neatly reflect piano double stave notation, where middle C is in the middle, and the treble staff is marked with a "G" clef (aka treble clef) and the bass staff by an "F" clef (aka bass clef).)

------

------

------

---G--  indicated by the circle of treble clef (a stylised letter "G")
   F
---E--
   D 
  -C-    middle C
   B
---A--
   G
---F--  indicated by the blob and two dots of bass clef (a stylised letter "F")

------

------

------

MINOR KEYS are where we get the 4th triad type (aug) and the other two 7th types (m(maj7) and dim7) - thanks mainly to the harmonic minor scale. Melodic minor also produces the first two types, but it's a good idea to remember: "harmonic" means related to chords; "melodic" means related to (er...) melodies. So while we can get chords from melodic minor, generally we don't. (although this is where jazz musicians will start raising objections....... don't listen to them, they just like to confuse everyone...)

[Silly Moustache]

Originally Posted by Bob Womack

Another, simpler way to say the answer to question one is that the C chord we use is not made up only of the fretted strings but also the un-fretted but sounded G to form the triad.

Bob

This is what I was going to say - but with the addition that you can play the 6th string open (e(a III) or better - as a G ((V) which gives you the option of a I-V-I-V bass progression.

You can also add the G on the 1st string if you wish.

As regards a C minor - the three notes are C, Eb & G , and so most of us would use the Am shape barred at the 3rd fret - i.e. C,g,c,eb,g.

Giving you the 1,5,1,b3, 5. - a Cminor.

Hope this helps.