When to Use (and When to Avoid) Minor 7th Chords

So, if you’re not interested in the nitty-gritty of barbershop arranging, look away now. We have a very specific question to consider today, vital for anyone who has to choose which chords to use in a particular context, but pretty irrelevant for everyone else. Though, it does have a wider context, which both gives it a broader applicability and risks muddying the waters.

Here’s the question, raised in a group of barbershop arrangers, that set me off:

Question; why is the barbershop style opposed (for lack of a better word) to the min7 chord? I personally love the sound of it, and yet I have been told by other barbershop arrangers to avoid it where possible. Just curious why?

As you can imagine, we had some responses leaping in to the defence of the minor 7th’s beauty and/or the arranger’s right to pick whatever damn chord they choose (it wasn’t clear exactly which they were defending, but it was clear that they considered the advice out of order). So we need to step back and ask: is the barbershop style opposed to the minor 7th?

And the answer is: actually, to an extent, yes. From the Music Category Description in the Barbershop Harmony Society’s Contest and Judging Handbook, we find:

Songs that feature the minor seventh frequently and prominently are discouraged

However, the minor 7th is named as one of the stylistic chords in the barbershop chord vocabulary, so it isn’t as simple as being ‘opposed’ to it. The point in this rule is about songs whose primary harmony requires a lot of them, to the extent that become a defining colour of the song. And the problem with this kind of song isn’t that the minor 7th is unlovely, but that if it is dominating the musical flow, there will be a commensurate dearth of the major triads and barbershop 7ths that ring like billy-o and create the classic expanded sound that the style so loves to fetishise.

This is one of those questions that on the surface looks like a Music Category issue, but actually turns out to be as much or more Singing and Presentation Category issue. MUS folk are often keen not to look like chord nazis and so will go all comme-ci, comme-ça about proportions or durations of individual chords. Meanwhile, the Singing judges are shaking their heads at the lack of expansion and the Presentation judges are yearning for greater emotional intensity. You get softness, tenderness, smoothness and intimacy from a minor 7th - all wonderful for barbershop moments, but not the stuff out of which high-octane medal-bids are made.

So, that’s why you may get people saying, ‘hey that’s not the most barbershoppy chord available’ in a general sense. But then, the conversation moved on and the original poster added:

I had a couple people look over a few of my arrangements who told me that a minor triad was a better barbershop choice than a min7.

Which, to my mind, is actually a different kettle of fish. The barbershop style ‘opposition’ to the minor 7th arises from a desire to pack songs full of chords with major 3rds in them. If someone is advising using a minor triad instead of a minor 7th, then it’s much more likely to be a question of syntax than ring.

The syntactical question about when to use a plain triad, and when to use a triad with added 7th actually generalises to versions with either major or minor 3rds. The plain triad is the more stable chord, while chords with 7ths in them are signalling that they are en route to another chord. You get a zingier sense of momentum, as well as more ring, from the dominant-type 7ths (with their tritone tension and all), but both types say, ‘not stopping here, just passing through’.

Which gives two specific take-aways immediately.

First, never cadence onto a minor 7th chord. So, for example, in ‘What a Wonderful World’, the phrase ‘I see them bloom for me (chord III7)...’ clearly needs to cadence onto the minor triad ‘...and you’, as it is a temporary stopping place. Melody and lyrics mark your cadence-point, and the point of arrival needs to be confirmed by a plain triad.

Second, minor 7ths are ideal for passing chords, i.e. to harmonise notes in the melody that don’t belong to the primary harmony. In particular, melody notes a 4th above the root (often found when passing between the 3rd and the 5th) work brilliantly harmonised with a minor 7th on a root a 5th higher than the pillar. You can use barbershop 7ths for these, but they clamour for attention, what with their ringy thirds and need for accidentals. And you don’t always want to draw attention to in-between notes; in these cases the diatonic smoothness of the minor 7th is a positive advantage.

So, that’s when to use a triad as primary harmony (for moments of rest/stasis, most particularly at cadences) , and when to use minor 7ths in passing (to create flow in the musical narrative). But when, if ever, should we use minor 7ths as a pillar chord?

I spent some time vamping through various songs at the piano while I thought about this one. The first thing I noticed was how rarely barbershop standards actually do use the minor 7th; apparently the style has traditionally done what the theory says it does. Just for fun, I started playing with substitutions. You can actually play ‘Down Our Way’ without any sharps or flats (i.e., with minor 7ths the whole time instead of secondary dominants) except for the one accidental in the melody on ‘gang of mine’. Try it - it’s good for the brain to be weirded out every so often.

At this point, I had a working hypothesis that you could probably use a minor 7th as a pillar at any spot where you could use a barbershop 7th. Or indeed a half-dim 7th - there is a functional parallelism in the three in their root movement and voice-leading. Of course, sometimes the melody note mandates that it has to be one or the other, but you can still sense-check the progression using hypothetical substitutions. (I tested this with the chorus of ‘Georgia on Your Mind’.)

After sleeping on it, I had refined this pragmatic guideline to a more specific rule. You can use a 7th chord in the primary harmony if the 7th falls by step onto the 3rd of the following chord. That is, it is voice-leading not sonority that determines whether you can add a 7th to a minor triad and have it make sense. Try it with ‘Down Our Way’ - it’s the good old circle of 5ths in action, and it works whichever flavour of 7th chord you use.

(Oh, and then I had to try ‘Down Our Way’ with half-dims all the way, and they really don’t go with the melody! But I also thereby demonstrated that a half-dim 7th really needs to be followed by a barbershop 7th. Your ear knew that anyway, but I mention it in case you have one of those, ‘why does my chord choice sound weird?’ moments, and this solves the problem.)

Well, this turned out quite long. But I’ve found it useful, as I started out knowing which to use in any context, but not being entirely sure how I knew. And now you know how I know too.