A quick guide to difficult chords for duet concertina players

There's no need to be frightened by a symbol that says something like Cm13, A7sus 4 or even D/C. Working these things out is just a matter of arithmetic - sometimes tiresome, but arithmetic just the same.

But here's something that might help. The deal is this - if you have the type of chord you are looking for (maj 7, dim, add9 etc) written out on the keynote of C, you should be able to work out the notes in the chord you want by transposing - just as you do when you writeout a tune in a key that is comfortable for your instrument.

So, if I give you the chord of C7 (C, E, G, Bb), you should be able to transpose the notes to the key of D to make D7, to the key of A to make A7 or to Bb to make Bb7 - and so it goes. (By the way, the answers are: D7 = D, F#, A, C; A7 = A, C#, E, G; Bb7 = Bb, D, F, Ab.)

You'll find a short appendix explaining very briefly how this arithmetic works. I have tried keep it simple and practical! Swots who are into composing might like to know that there is also a body of knowledge about how chords follow on from each other - but people go to college full time to learn that stuff!

Major and minor

C major, written just C, contains the triad of the notes C, E and G, as I'm sure you all know. These notes can be played in any grouping or inversion and will still sound good, and you can either double notes for emphasis, or leave some out.

C minor, written Cm, has minor or flattened third, making it C, Eb and G. Again try it in different inversions.

You will also see a thing called C augmented or C+ - it's made up of C, E and G#.

Seventh heaven - or hell?

The sevenths you are most likely to see come in a variety of forms. The dominant seventh, written C7, includes the notes C, E, G and Bb, and is by far the most common. You may find that Bb a bit of a surprise, but that should help you to remember it!

Like many of the rest of the chords we are going to look at, the dominant seventh is great for adding tension - that is, making you feel you want the harmony to change in some way, often to something sweeter such as a major or minor.

The minor seventh chords are similar to the dominant seventh, but are based on the minor chord we've just seen.

Cm7 includes C, Eb, G, Bb.

What's usually meant by the major seventh or Cmaj7 includes C, E, G, B. Compare it with C7, and be aware of the important difference!

The augmented and diminished 5ths turn up a lot in tin pan alley songs.

C dominant 7th augmented 5th, or C7+5 includes C, E, G#, Bb.

C dominant 7th diminished 5th or C7-5 includes C, E, F# (equivalent to Gb), Bb.

C major seventh augmented fifth, written Cmaj7+5, contains C, E, G#, B.

There's also C major seventh diminished fifth, or Cmaj7-5, which includes C, E, Gb, B.

Next, C diminished is written Cdim, and includes C, Eb, F#, A.

C half-diminished (I'm sure you could also call it C minor 7th diminished 5th) is written either Cm7-5 or with a another little degree sign but with a slash through it. It includes C, Eb, F#, Bb.

And the curious C minor/major seventh, written Cmin/maj7 includes C, Eb, G, B. I've never seen it anywhere, but you never know where it might turn up.

Additions and suspensions

This author did not really understand the difference between an addition and a suspension until Dave Abbot took the trouble to explain it. He says, and I'm sure he's right, that a suspension is what you have when the third is taken out and replaced with the addition. The triad has first, third, and fifth. The add4 has first, third, fourth, and fifth. The sus4 has first, fourth, and fifth. It's more common to find sus2 and sus4 than add2 and add4 because of all the clashing notes.

This is in contrast to the addition situation, where quite often you typically you play the first, third and the addition (see below.)

Perhaps a more important piece of information that C added ninth or Cadd9 is C, E, G, D.

C minor added ninth or Cm add9 or Cm/9 is C, Eb, G, D.

C suspended 4th, or Csus4, is C, F, G.

C6 is C, E, G, A.

Cm6 is C, Eb, G, A.

Let's talk about extensions...

I'm referring to the big 'numbers' chords: the ninths, elevenths and thirteenths. Played with all their notes, these can sound terrible on a concertina. To me, it's the equivalent of mixing together all the colours on an artist's palette - mud.

The solution is to leave bits out, and it's sometimes said that the first note (C), the second (E or Eb), and the top note are all that you need. Try that, certainly, but experiment - you might wish to include the fifth and/or the seventh!

I have included most of the 'numbers' chords you are likely to see - if you need any more, it might be wise to buy a book - or hire an interpreter. However, If you're like me, you will be pleased to know that a seventh or a ninth will often stand in place of one of the elevenths or thirteenths.

Also, a small word of warning: if you find sheet music or books of 'chords to the hits' where 13ths outnumber any thing else, I suggest it is likely that the sevenths and ninths may be easier to get your head around and may work well on their own - and you might not meed any higher numbers at all.

There are three main ninths:

C9 is C, E, G, Bb, D.

Cm9 is C, Eb, G, Bb, D.

Cmaj9 is C, E, G, B, D.

There are three main elevenths:

C11 is C, E, G, Bb, D, F. The D and G are often left out.

Cm11 is C, Eb, G, Bb, D, F.

Cmaj9+11 is C, E, G, B, D, F#.

And there are three main thirteenths.

C13 is C, E, G, Bb, D, F, A.

Cm13 is C, Eb, G, Bb, D, F, A.

And Cmaj13 is C, E, G, B, D, F, A.

The polychords

The term 'polychord' properly means two chords together, but for most of the time these 'slash' chords are just chords with an unexpected bottom note denoted by the slash symbol. These little chaps are easy to work out!

C/B would be B, C, E, G

And C/G# would be G#, C, E, G


What do the numbers mean? In the key of C there are eight notes: C, D, E, F, G, A, B... and C. But each note has another, general name.

In the key of C:
Db is the minor second
D is the major second
Eb is the minor third
E is the major third
F is the perfect fourth
F# is the augmented fourth (jazzers may call this the flattened or flatted fifth)
G is the perfect fifth
G# is the augmented fifth
A is the major sixth
Bb is the minor seventh
B is the major seventh and
C is the octave.

PS - I received the following letter from a certain Brandon Burt. I can't guarantee that he's right, but what he says struck me as both plausible and entertaining. Dear Gavin, I enjoyed your page about chord construction. It seems only a few people are willing to spend time putting up useful information regarding music; most others are selling CDs or gushing about their favorite new corporate neo-grunge band or whatever :) You mentioned that the difference between a suspension chord and a chord with an additional note isn't always clear, and it made me actually remember a fact from music theory class years ago! This does not happen often, so please congratulate me. I think the most usual sus chords are sus4 and sus2, although I think there may be a sus9 or susAnythingElse, depending on the context. It comes from an old voice-leading technique of letting a single voice from the previous chord be "suspended" ... or not changing right away to the appropriate note in the new chord. The example in the IV-I progression: say you have three-voice harmony and they are singing F/C. In the blandest progression possible, the top two voices would immediately move together and the group would be singing C -- however, perhaps lucky Pierre in the middle (singing F) has had a few too many glasses of absynthe and is a bit slow on the uptake. Then, momentarily, the trio is singing Csus4 before Pierre catches up. Naturally, Pierre isn't the only one who thinks this sounds great, and the group starts using the progression all the time. The way a sus4 chord ordinarily resolved was by moving the suspended 4th down to the 3rd. Similarly, the sus2 resolved by moving the suspended 2nd down to the root. Of course, in real music this kind of resolution didn't have to be that explicit, but the chords were thought to have that tendency; in modern music the suspended tone can just appear out of the blue without having to be held over from the previous chord, but the name has stuck. I guess I would think the real difference between an addition and a suspension is that, e.g., a C7sus4 can be fully constructed from four tones, whereas a C7add4 (not very commonly used, I'll admit) would require 5 tones. If this is wholly incorrect, please enlighten me :) Otherwise, I just wanted to thank you for having valuable information on your web site, and to say bravo, and all that. Sincerely, Brandon

This site is intended primarily for duet concertina players, but may also be useful to other people whose muscial knowledge is self-taught or in the process of being built up. It is not intended for experts! However, if you find anything wrong or have any comments, please address them to me, Gavin Atkin at gmatkin@clara.net If you are interested in killer dancebands or designing and building boats, jump to my homepage at http://home.clara.net/gmatkin/homepage.htm.