Avicii’s Wake Me Up is a bastardisation of several styles of popular music from the past 50 years, and ties them all together in a horrible cocktail of 125BPM nonsense. Still, it's kind of catchy right? Here’s why:
The song is incredibly simple, using a basic 4-chord lick which can be found a number of pop songs, and never variates from it. The use of repeating perfect cadences is what embues the music with a feeling of urgency, which is in turn reinforced by the busy, galloping guitar rhythms. Simple song structures are often blamed on lazy writing by music snobs like me, but it’s usually quite a calculated, cynical move. If a song uses same basic musical idea the whole way through, it’ll be instantly memorable to anyone who has heard even a small section of it.
Melodically there is little going on, as a blues scale carries both the vocal melodies and the synth hook. This is the same scale that you’ll find in every Muddy Waters song, every Led Zeppelin guitar solo, and almost every song on the new Arctic Monkeys album. In short it’s been done to death, it’s in the public consciousness, and it can easily be exploited for a quick, memorable riff.
The variation that there is within the song comes from ‘build and break’ structure originally used by 90s Trance music, but which is now utterly ubiquitous in the world of poppy electro-house. What this means for the listener is there’s a quieter bit for people to dance to, followed by a loud bit people can jump up and down to. This 'build and break' model keeps the listener occupied with changes in the song, whilst keeping the simplicity of the actual music intact.
The song appropriates a sort of naff, ‘toe-tapping’ half-time rhythm taken broadly from country music, and recently popularised by artists such as Mumford and Sons. By coincidence or design, this sort of music actually segways surprisingly easily with Electro-House, since both styles generally share a tempo of around 125BPM.
The vocals are probably least objectionable element of the song. Aloe Blacc's soul style represents a nod to the original dance music of the 80s and early 90s, when soul samples were frequently used to create hooks for house and trance tracks.
Overall, Wake Me Up is catchy because it's simple. It doesn't challenge the listener, uses repetitive lines and ticks a bunch of zeitgeist-y boxes. Sometimes though, that's all you need.