Harmonising a simple song

I'm often faced with this problem: I have a simple melody - either one I wrote, remembered or found - and I want some accompaniment for it. For that I need to know "the chords".

How do you get about identifying the chords for a song ? People who are experienced with instruments that play chords - piano, guitar, etc. - are said to just hear the chord progression when they hear the melody. Well - definitely not the case for me :)

So - if like me you can't hear chord progressions, here's a little method I've developed, which works for simple pieces. It's worth noting that there is more than one way to harmonise a melody - there isn't a "right" way. What I'm presenting here is, well, a simple way !

Step 1: Work out the main rythm

We want to work out when the chords would typically change. Note if you can intuitively work out the bass line - or even just the shape of the bass line - then you already have the main rythm, and can skip this section.

So for me the best way to work this out is intuitively: listen to the melody, and tap your feet or clap your hands. There you have it ! The notes where you clap your hands are the notes where you're going to change chord.

If you don't get this intuitively, no worries ! For a simple tune - and this method here is for simple tunes - you're pretty safe following these rules:

• If the time signature is 4/4, then you get two "beats" per measure, one on the first note, and one exactly half way through
• If the time signature is 3/4, then you get one beat per measure, on the first note
• If the time signature is 6/8 or 12/16, then likely you get two beats per measure, one on the first note, and one exactly half way though

Step 2: Work out the bass line

Now you've got the rythm, you need to work out a simple bass line. Again, some people will do this inutitively - if so, great ! For myself, I can get an idea of the shape of the bass line while listening to the melody, but not the actual notes. Note that working out the bass line is the hardest step !

With the shape of the bass line you will know:

• When the chord changes happen
• Whether the bass note of a chord is higher or lower than the previous one, which is a good hint as to what it should be

But what if you don't even get the shape of the bass line intuitively ? No worries !

First you need to work out the key of the song. I won't detail this here (you do need a little bit of music theory to do these things), but you need to look for several things:

• The key signature telling you the number of flats and sharps
• The notes on which the piece starts/ends/resolves. This should allow you to work out whether it's a major key, a minor key or something different (e.g. a Dorian key, which is not uncommon in traditional music).

Once you have the key, look for the following in your melody:

• A note that is the key, and falls on one of the beats you've identified. At that point you can be quite sure the bass note is the same as the key ;
• A group of descending notes (starting on the beat), where the last note (the one before the next beat) is the key. Again, you can be quite sure the bass note for the first note of the group is the key.

Now to the other notes ! On a first pass, I would use roughly the same logic:

• If the group feels like it's flowing forwards, I'd use either the first note or the lowest note of the group as the bass note (try to use intutition, but don't worry about it too much yet)
• If the group feels like it's coming to conclusion, I'd use the last note as the bass note

You now have a provisional bass note for every beat. But at this stage they're only provisional. Now you should enter the melody and the bass line in your favourite music editor. Then listen to it. That's right, this bit needs to be done by ear ! It is music after all, we can't make it only by following methods...

So listen to the piece, and notice where the bass line doesn't feel right. And correct it ! Trust your intuition here, you have no other choice. Why didn't it feel right ? Because it was too high or because it was too low ? When changing the bass notes, ideally:

• See if you can use one of the other notes in the group
• Use a note that it's the key/mode you've identified earlier.

Keep at it - and eventually you'll get something that works for you. It may be that it worked for you right away, and didn't need any corrections - that's fine !

Step 3: Work out the chords !

Now you've got the bass line, this should not be too hard. First you need to know all the chords in your key. There are many online resources that provide those. Then, for each bass note, simply look at the list of chords in your key, and insert the chord named after the bass note.

So for example if you're in A minor, and you have a bass note that is a C then the chord at that point would be a C major.

Once again, insert those in your music editor, and listen. Does it sound ok ? If not, can you identify individual chords that sound wrong ? Once you've found the wrong chord, there's a few options:

• Maybe you got the bass note wrong, re-visit that !
• Maybe a chord change wasn't needed, and it's best to continue with the previous chord
• Maybe it's a chord inversion, where the bass note is not the name of the chord. Try other chords that include the bass note

And that's pretty much it ! Remember this is just a simple approach for simple music - it's unlikely to be fruitful on advanced jazz or classical music !