Two-part harmony usually does the trick
In most forms of Western music, there is a clearly identifiable melody, whether that’s sung or played on an instrument. That melody is meant to stand out from all the other instrumentation around it. If you’ve done a good job and with a few repetitions, it may even stick in the listener’s memory.
The melody can often be enhanced with harmony – not in the form of a musical accompaniment but as a vocal or instrumental line running in parallel to the melody.
Here’s a simple melody …
And here it is again with a harmony …
What we just heard was a two-part harmony – the melody plus one additional harmony line. And, more often than not, two-part harmony is enough – not to satisfy a barber’s shop quartet or a huge choir, but for most purposes.
Typically, the notes of the harmony line will be two notes along the scale higher than the melody. The harmony is then said to be in thirds. So, if the piece is in C major and the melody goes G A B C, the harmony will go B C D E. Of course, there’s nothing to stop you singing or playing the harmony an octave lower, below the melody line, because the notes are still the same. This would work well if, for example, the main singer was female and singing relatively high and the harmony was being sung by a man with a lower voice.
Is harmony just an intuitive thing?
So, do you need to know anything about harmony to harmonise effectively? In the case of two-part harmony, probably not because we’ve all heard so much harmonised music that we can work it out for ourselves with a little trial and error.
The difficulty might come if the chord progression extends outside the home key and introduces some notes that are not in the key’s scale. Now the harmony has to adapt. Again, this may get sorted with a little trial and error but it obviously helps to know why the harmony might have to include an unusual note here or there or even stay on the same note sometimes, even though the melody is shifting up or down.
Two-part harmony in current hits
We all know just how commonplace vocal harmonising was in early pop and folk music. With singing duos like The Everly Brothers or Simon and Garfunkel, the two-part harmonies backed up by a simple rhythm track are just about all you get.
But what about now? I listened to the top five Billboard hits as of the beginning of April 2021. Here’s what I found:
Peaches – Justin Bieber (feat. Daniel Caesar): There’s a small amount of two-part harmony going on in the bridge (look for the words ‘Yorker’, ‘torture’, ‘hold her’ and ‘Rimowa’.
Up – Cardi B: There are hints of harmonising going on but nothing clear-cut.
Leave The Door Open – Silk Sonic: All of the backing vocals are harmonised.
Driver’s License – Olivia Rodrigo: There are harmonies on the bridge and with all the backing vocals.
Save Your Tears – The Weeknd: There are hints of harmonies in the closing section.
Looks like two-part harmony is going strong, although not anywhere near as obviously as you might have seen in the 50s and 60s. I expect that’s heavily influenced by the genres which dominate the charts at the moment and possibly also the fact that there are far fewer duos, guitar bands or boy/girl-bands. Another shift I detected was quite a subtle use of harmony which is almost definitely electronically generated in post-production. I’m all for subtlety so that’s fine by me.