The term Triad is something you will come across a lot throughout music theory. It is one of the most basic and essential forms of a chord, and is how the majority of western music is constructed.
A triad is described by the Oxford Dictionary of Music (2006) as a ‘Chord of 3 notes’.
The dictionary also defines several different types of triads, however knowing the different types of triads isn’t necessary at grade 1.
As we discussed earlier, the term Tonic is the first note in a scale, and is the note a key signature is named after. A tonic triad starts on a tonic.
Therefore, a tonic triad is simply a chord consisting of 3 notes, with the first one starting on the tonic.
The other notes in the tonic triad other than the tonic, is the third and then a fifth above the starting note.
Different Tonic Triads
In C major the first note of the scale is a C. Therefore the tonic triad starts on a C.
The second note in the triad is, as we discussed earlier, a third above the starting note. This means as C is the starting note, a third above C is E. So the first to notes are C and E.
The third note is a fifth above the starting note. A fifth above C is G. Making the tonic triad C-E-G:
The G Major triad is constructed in the same way. G is the tonic note and therefore the starting note of the triad.
B is a third above G, so is the second note of the triad
D is a fifth above G so is the third note of the triad.
This makes the triad G-B-D:
The final two triads, D and F major are constructed in the same way.
For grade 1, you need to know the tonic triads for C, G, F and D Major.
For those doing grade 1 with Trinity, you may be expected to know how to label a tonic triad.
As the tonic is the first scale degree, the chord is therefore labelled I. (The number 1 in Roman Numerals).
All chords are labelled with Roman Numerals, and in later grades understanding chord labels will be necessary to understand and write music.
If labelling a chord on sheet music, the label is put just below the chord on the stave:
Additionally, you may be expected to recognise a tonic triad as an arpeggio. An arpeggio is when the notes of a tonic triad are played one after another, starting on the tonic, with the highest note being a tonic, and then going back down, as so:
Finally, remember to check whether you need to write in a key signature or not, and whether you need to write any accidentals in (remembering you don’t write in accidentals that are in a key signature).