So, if you're taking a harmony course, you've certainly come across the concept
of secondary dominants and endless exercises where you're given a piece of sheet music in which you
have to label all the secondary dominants. Well, today I'm going to give you a simple trick
to spot and label secondary dominants and, for this video, we're only going to consider
the V or the viio of something -- like a V/ii, or a viio/ii,
or a V7 or a viio7 of IV, and so on. We won't get into secondary
neapolitan 6th chords or augmented 6th chords, Just secondary V and viio chords.
And also, for simplicity, we will only look at pieces in major keys. "If you're new to mDecks Music,
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let's power up the circle of fifths in five simple steps. Step one: find the key of the piece. Remember,
we're only looking at pieces in major keys for this video. To do that you just need to look at the
key signature. If it has no accidentals, you're in the key of C major. If the key signature has sharps,
then the key is a note a half step above the last sharp. So, here the last sharp is a G#, and a
half step above G# is A. So this piece is in the key of A major. Basically, the last sharp is
the leading tone of the key. And the last sharp in this piece, is A#. So this is in the key of B.
If the key signature has flats then the key is the second to last flat. So here, the second to last is
an Eb, then this is in Eb major. This one is in Ab major. If there's only one flat, then it's
in the key of F major. Step two: draw a circle of fifths in the key of the piece. Yes! It is essential
that you know the circle of fifths. It will save you tons of time when studying any music theory
related topic. And to put a circle of fifths in a key, just draw the standard circle of fifths in C,
and then turn it around until the note that represents the tonic of the key is at the top.
So, this is the circle in C major. Let's say we have a piece in G major -- with one sharp in the
key signature. Then, all we have to do is rotate the circle counter-clockwise once, to get the G at the
top, and we have a circle of fifths in the key of G major. Or if we're in Bb major -- with two flats --
we rotate the circle yet again until the Bb is at the top. And we have a circle of fifths in
the key of Bb. Step three: draw a straight line from the 11 o'clock position across the
circle, to the 5 o'clock position. All the notes to the right are the diatonic notes. These are
the notes of your major scale in that key. So this circle is in the key of C, and these notes
are in the C major scale. Here's the circle in G major. So these are the notes in the G major scale.
And here's the circle in Bb major, and these are the notes in the key of Bb. Just make sure
to use the correct accidentals. Don't mix flats with sharps! Step four: label the notes as degrees.
So, C is the I, D is the ii, E is the iii, F is the IV, G is the five, A is the vi, and B
is the vii. The cool thing is that these labels are the same for every key. In the key of G, G is
the I and, D is the V and, A is the ii, and so on... So, once you know where these labels go, you'll
never have to change them ever again. And Step Five: write the leading tones for each diatonic note.
The leading tone is a half step below the note. So the leading tone for C is B. The leading tone for G
is F#, and the leading tone for D is C#. You get the idea... And for the IV chord -- the one at
11 o'clock -- we're gonna write the leading tone of the I, lowered by a half step. So, we turn this B
here, into a Bb. If the circle was in the key of G we would do the exact same thing. The leading
tone for G is F#, for D is C#, and so on... And the only exception is for the IV chord.
For this chord, you are always going to pair the root of this chord with the b7 of the key
that you're in. Not the leading tone! The leading tone of the IV chord is already in the key. So, it
won't show as an accidental in the score. But the b7 of the key will appear as an accidental.
So for C -- the IV, at 11 o'clock -- we change this F# to an F natural, lowering it by a half step.
Now we have an accidental to look for, that will help us identify something that is targeting
the IV. In the key of Bb, we have an A as the leading tone for Bb then, E is the leading tone
for F. Then, a B natural for C, and so on... Remember, the leading tone is always a half step below the
target. And for the IV chord (Eb), we take this A, and lower it a half step to Ab. That's it!
With this information you are ready to spot and label any secondary dominant in a piece of music.
If you come across an accidental that isn't paired with one of your diatonic notes,
you're probably dealing with a more advanced secondary function, which we will talk about
in a later video. So let me show you how easy it is to use this new enhanced circle of fifths.
Here I have a measure from Beethoven's Sonata Opus 14 No.2, and the one sharp in the
key signature tells me that we're in the key of G major. Take a look at this measure. We have a couple
of accidentals, and they are sharps. These are great candidates to potentially be secondary dominants.
The first one is a G#. So, we look at our new and improved circle of fifths, and we look for a
leading tone that's a G#. And of course, we find it here! G# is the leading tone to A.
So this is almost certainly a secondary dominant that targets an A chord in the key of G.
A is the ii in G major, so you can assume with confidence that this is going to be a secondary
of ii. Now, it could be the V/ii, or the V7/ii, or the viio/ii, or the viio7/ii.
The only thing you have to do, to figure this out, is to see if the next note in the circle -
moving clockwise - appears in the chord. That would be an E, in our case. That's because the next note in
the circle is always the V of the previous note. Remember, this is the circle of fifths. So, is there
an E in this chord? Yes there is! So it's either a V/ii or a V7/ii. And there's a D right here. So,
that means this is an E7. So this is a V7/ii. Of course, it's an inversion, because the
lowest note is not an E. It's a G#. So we write V65/ii. 65 because G# to E
is a 6th, and G# to D is a 5th. Then we see a C#. Probably another leading tone...
there! C#, the leading tone to D. And D is the V. So we already know this is a secondary of
V. Now, is it a viio, or is it a V? To figure it out, we look for an a the next note
in the circle after D. In other words, the V of D. If the A is there, then it's a V of D. If
it's not, it's a viio of D. And there it is! An A in the bass. So this is a V of D.
If there's a G then it's an A7 the V7. If not, then it's a simple a triad - the V.
And the G is right here. So this is an A7, which we can label with confidence as a V7/V.
Let's do another example by Beethoven. Here we're in the key of Ab, and here is the enhanced
circle of fifths for the key of Ab. In this measure we see the accidental A natural. Our circle
tells me that this is probably targeting Bb, the ii chord. Now I look for the next note in our
circle of fifths: F. Is there an F in our chord? Yes! This means that this chord is a V/ii,
an F chord. Now if I can find the b7 of F - Eb - then, I'll know that it's a V7/ii.
And there it is! Eb. So, this chord is an F7, the V7/ii. All right. Last example. Let's
do the same thing, only with some Chopin this time. Here we're in the key of Eb. In this measure
here, we have two chords that we can examine. Here is our circle of fifths in the key of Eb.
The first accidental in this measure is a Db. When we look at our enhanced circle of fifths,
we can see that this note is paired with our IV chord: Ab. We're probably targeting Ab here,
the something of IV. Now, we look to see if an Eb is present - the next note in our circle.
And yes! There is an Eb. Well, that means this is a V7/IV, an Eb7 chord.
Now, you may have noticed that I just skipped a step here, by immediately labeling this
as a dominant chord, without first looking for its b7. And that's because the V/IV
doesn't really exist! That's just a I chord! The IV chord is the only chord in the circle, where
the decision of whether it's secondary V - being a V or a V7 - does not need to be made. It's always
a V7! The next chord in the measure contains an E natural so this is a secondary of the ii: F minor.
If there's a C the next note in the circle of fifths then, we're dealing with some sort
of V. However, there isn't a C here at all! What does this mean? Well, it means that we're dealing
with a viio chord. This means we have either an Eo or an Eo7 -
a viio/ii. And there is a Db in the chord. So now we know that we're dealing
with a viio7/ii, and the fact that there were four different notes here -
and not three - was also a giveaway, indicating a viio7 chord. Thanks again for
watching. As always, I hope this was helpful. We've prepared a PDF with the enhanced circle of fitfths
in all keys, which you can download right now if you're an exclusive access member. And if you're
not a member, you can become one by clicking on the join button or the link provided, to download this pdf,
along with all the other exclusive content that we publish on a regular basis. Thanks for watching!