How often have you been listening to the radio thinking I’ve heard this before? You know you haven’t heard the song itself before, but the song’s melody seems familiar. Sometimes you can even name the song the melody reminds you of. But, you can’t really blame the musicians. They only have a small amount of notes available to them. Or, maybe we can blame the musicians. Maybe it is just a lack of creativity on their side. Come on, I need to know where to point my finger.
First we need to know what a melody is. Just saying it’s a set of musical notes played in repetition to create a recognizable hook is not enough. We need some parameters to work with. Let’s say our melody stays within a single octave, giving it access to 12 possible notes and a pause. It has at least one note in it and that note can be a whole note, a half note, a quarter, all the way down to a 64th note. That means each note can be one of seven lengths. At this point we can already produce 91 different melodies with just a single note. Of course these won’t be very interesting melodies, but I’ve definitely heard (good) songs were the melody was nothing more than a single note repeating itself.
Within these rules there are 68.574.961 different melodies possible with exactly four notes. Now, a lot of these melodies will sound fairly similar, granted. To an untrained ear ABAB will sound almost the same as BCBC. In this set of rules there is also a melody consisting of four pauses, essentially silence.
So let’s try a slightly different set of rules. A note is still a full note, a quarter, an eight, etc. up to a 64th note. But instead of using the 12 notes of a single octave and a pause, we say that between two notes the difference in pitch can be anywhere from 6 notes lower to 6 notes higher. This is still not a perfect mathematical approach to a melody, but at least we eliminate all the very similar sounding melodies. With these rules we can only produce seven melodies with just one note. We can produce 753.571 different melodies that contain exactly four notes (well, 753570 if you don’t count the all pause melody).
Let’s say we don’t want a melody to be longer than 64 notes. Within our rules there are 2.657.100.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000 possible melodies. Okay, sure, that also contains silly stuff, but we can’t tell what music is going to be like in ten, fifty or a hundred years.
Let’s say there are a hundred new albums released every day and an album on average carries 10 songs. That’s 36.5000 songs being released every year. (I don’t know if these numbers are realistic, it’s what you call a high estimate). At that rate the music industry could release songs with unique melodies for 727.970.000.000.000.000.000.0000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000.000 years. Keep in mind that it only takes 5.000.000.000 years for the sun to start to turn into a red giant and destroy earth and according to the Big Rip theory it will take a mere 22.000.000.000 years for the universe to start tearing itself apart.
So there it is. It seems we can safely wag our fingers at musician for reusing melodies. So next time you hear a song with a melody from an older song quietly shake your head and think about the literally quintilliards of other melodies they had at their disposal. Or, you could ignore it and just try to enjoy the song anyway.
p.s. Before you start screaming that in my rule set there is still a lot of melodies that are very similar; I know the above is a somewhat blunt instrument approach. However, I’ve only taken a few variables that make up a melody into account. For one, I assume the difference between two notes is equal regardless of the notes played. This is really only true for modern music. There are so many different variables that make up a melody that the numbers above are likely to be even higher and even if 99% of the melodies sound too similar, the remaining 1% of melodies are still enough to last us far beyond our own destruction.