A flat-VI chord is a major chord built on the lowered 6th degree of a major scale. In C major, the 6th degree is A. Lowering it gives you Ab, and a major chord built on that note gives you the 3-note chord Ab-C-Eb: the so-called flat-VI.
In pop music genres, the flat-VI chord quite often appears either as a passing chord on its way down to V:
C Bb Ab G C (I bVII bVI V)
…or on its way up to I:
C G Ab Bb C (I BbVI bVII I)
If chords-first is your favourite songwriting process, but you find that your songs are sounding boring or aimless, there are some fixes you can try. Read “Writing a Song From a Chord Progression” to get ideas on how to avoid the typical problems of the chords-first process.
But there are other interesting ways that the flat-VI can work. Here are some to experiment with:
1. Paired Up With a Minor iv-Chord
Example: C Ab Fm C (I bVI iv I)
In traditional harmony, both the flat-VI and the minor iv-chord are known as modal mixtures, in the sense that they both come from the key of C minor, not C major.
In that sense, it sounds more like it’s the C chord that’s the intruder, as if the key of the progression is actually C minor, and you’re using a C major instead. It doesn’t really matter; moving from the flat-VI down to the minor iv should work in almost any progression, no matter what you do before it or after it.
2. Allowing It To Move to Flat-II
Example: C F Gsus4 G Ab Dbmaj7 C (I IV V4 V bVI bII I)
In this example, the Ab chord acts as a secondary dominant (s.d.) chord. That means that, for the moment, it is acting like a dominant chord of the flat-II in the sense that its root moves up a perfect 4th, like a real dominant chord does (Ab-Db), and it’s a major chord. (If you need to know more about s.d. chords, read this post.)
As you can see, once you’ve reached the flat-II chord (Db, or in this case, with the added major 7th Dbmaj7), you can slide quite easily down to the tonic chord to finish the progression.
3. Following It With Flat-III
Example: C Am Ab Eb Bb F G C (I vi bVI bIII bVII IV B I)
Chord progressions become stronger the more you use root movements of 4ths or 5ths. That’s why the standard I-IV-V-I works so well: the root moves up a 4th from the I to IV, and then up a 4th again from V to I.
In this example, there’s lots of 4ths/5ths root movement: Ab to Eb, Eb to Bb, Bb to F, and then G to C. So even though the middle part of the progression might make the key sound a bit muddled, it all works quite well, and once you’ve reached the IV-chord (F), you get pulled back into the original key.
My Recommendations for Using Flat-VI
Anytime you use a non-diatonic chord (i.e., any chord that doesn’t normally live in the key you’ve chosen), you pull the listener away from your key of choice. In pop music, that usually means that you should find a way back to your original key.
I think most of the time, that recommendation is going to work for you when you use the flat-VI. That chord has the ability to move you quickly into new key areas (from flat-Vi to flat-III, minor iv, or flat-II, for example). So you need to be careful that you don’t stray too far from home unless you’re purposely using the flat-VI to change key.
And I’ll just offer my standard recommendation here that you usually don’t need to worry about the boring nature of basic, simple chord progressions. A progression that sits in a key and offers no surprises (I-IV-V-I) will not be judged harshly by listeners, as long as the melody and lyric are interesting and somewhat innovative. Predictability in chords is usually not a problem.
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