Lesson 13: Tonic Triads
Building Tonic Triads
What are tonic triads? Tonic triads are simple chords with just three notes in them.
To build a tonic triad, we start by taking the first note from any scale (which is also known as the "tonic").
Let's make a tonic triad of D major.
We start by writing the first note of the scale of D major - D:
Next we add a note which is 2 notes higher (also known as the third degree of the scale). In the scale of D major, the note which is 2 notes higher than D is F#:
Finally, we add the note which is two notes higher than the last note - otherwise known as the fifth degree of the scale. In the scale of D major, the fifth degree of the scale is A:
The notes D-F#-A make up the tonic triad in the key of D major.
We can also build tonic triads in minor keys of course. The rules are the same, but we need to use the minor scale. In D minor, the tonic is D, the third degree of the scale is F (natural) and the fifth degree of the scale is A. So, the tonic triad of D minor looks like this:
Tonic triads are always built on the tonic, third and fifth degrees of the scale.
Adding a Clef to a Tonic Triad
You might be asked to add a clef (either treble or bass) to a tonic triad. You'll see the tonic triad on the stave, and will be told what key it's in, like this:
Remember that tonic triads are always built on the first note of the scale, so in this tonic triad, the lowest note has to be a G, because the key is G major. This note will be a G if we add a bass clef:
Adding Accidentals to a Tonic Triad
Sometimes you might need to add some accidentals as well as a clef. Look at this tonic triad:
Here we need to add a treble clef, so that the lowest note is a B, and we also need to put a flat sign on the B, to make it a Bb:
Naming the Key of a Tonic Triad
Another type of question you might get in the Grade Two Theory Exam, is to name the key of a tonic triad.
Again, you need to think first about the lowest note of the chord. Look carefully at the clef and the key signature or accidentals too. You should also look at the middle note of the chord to see if it's a major or a minor tonic triad.
What key is this tonic triad in?
The lowest note is A (it's in the bass clef), so it's a tonic triad in the key of A. The middle note is C#, which is the third degree of the scale in A major (in A minor, the third degree of the scale is C natural). So, this tonic triad is in A major.
Grade Two Tonic Triads
Here's a list of all the tonic triads you'll need to recognise for Grade Two, in both the treble and bass clef:
Finding Tonic Triads in a Melody
Sometimes you might need to find three notes in a melody which form a tonic triad when they're put together.
You'll be told what key the melody is in, and could see a question like this:
This melody is in C major. In which bar can all three notes of the tonic triad be found?
Because the piece is in C major, the tonic triad must contain the notes C-E-G. (They could be in any order.) Bar two contains the notes C, E and G, so that's the right answer. (Bar one doesn't contain a G, so it's not right!)