Hamden High School
Department of Fine Arts
Mr. Hicks
Major and Minor Triads I
A. INTERVALS
Musicians use the term interval to show the distance between two pitches. A half
step is the interval minor second (written m2) and a whole step is an interval of a
major second (written M2). All seconds use notes that are next to each other in
the alphabet (such as AB, BC. CD, etc.). The distance from A to C is a third,
because C is the third letter counting up from A.
Look at the keyboard and count the half steps from A to C. You will find that the
distance from A to C is three half steps, and so it is known as a minor third (m3).
Now count the half steps from C to E. You will find that this interval is four half
steps, so it is known as a major third (M3). See the following list of thirds and
notice that some are major and some are minor, depending on whether the
distance between the pitches is three or four half steps.
AC = m3
BD = m3
CE = M3
DF = m3
EG = m3
FA = M3
GB = M3
The other interval that you need to know for triads is the fifth. Fifths come in three
sizes: diminished (small), perfect (medium), and augmented (large). Most triads
use the interval of a perfect fifth (P5) from the root to the fifth of the triad. A
perfect fifth is seven half steps, a diminished fifth (d5) is six half steps, and an
augmented fifth (A5) is eight half steps. See the following list of fifths.
AE = P5
BF = d5
CG = P5
DA = P5
EB = P5
FC = P5
GD = P5
B. TRIAD THEORY
Root position triads are chords consisting of three pitches that use alternate letters of
the music alphabet. The basic triads of the musical alphabet are ACE, BDF, CEG,
DFA, EGB, FAC, GBD. The first letter of a triad is known as the root, the middle letter is
the third, and the last letter is the fifth. There are four possible combinations of
intervals within triads.
1. When the interval from the root to the third is a major third (M3) and the interval
from the root to the fifth is a perfect fifth (P5) the triad is major (such as CEG, FAC,
and GBD).
2. When the interval from the root to the third is a minor third (m3) and the interval
from the root to the fifth is a perfect fifth (P5) the triad is minor (such as ACE, DFA,
and EGB).
3. When the interval from the root to the third is a minor third (m3) and the interval
from the root to the fifth is a diminished fifth (d5) the triad is diminished (such as
BDF).
4. When the interval from the root to the third is a major third (M3) and the interval
from the root to the fifth is an augmented fifth (A5) the triad is augmented. No
accidentals occur in the natural musical alphabet (sharp, flat, or natural signs are
needed).
BASIC TRIADS:
GBD
FAC
EGB
DFA
CEG
BDF
ACE
All triads are based on the seven triads listed above. Memorize them!
The following symbols are used for the four qualities of triads:
C = C major triad
Cm = C minor triad (also C-)
Cº = C diminished triad (also seen as Cdim)
C+ = C augmented (also seen as Caug)
C. TRIADS ON THE KEYBOARD
Commonly Used Major Triads
C
B
E
Eb
D
A
F
Bb
G
Ab
Commonly Used Minor Triads
Cm
Fm
Em
Am
Gm
Dm
Bm
F#m
Examples of Diminished Triads
Bº
Cº
Dº
Gº
Examples of Augmented Triads
C+
F+
D+
G+