The science of Shazam: It’s a kind of magic

Feb 23, 2019
You know the feeling – you hear a song you love, but just can’t place the title or the artist. That’s where Shazam comes in – this revolutionary app identifies music in a matter of seconds. It may sound simple, but the process is incredibly complex – as we’ll discover as we uncover the sorcery behind Shazam.

What began as a call-in service when first created back in 2002, Shazam truly came into its own when launched for the iPhone in 2008. Now, if you hear a song you like but have no idea as to its name or artist, you can find the answer in mere seconds – without exposing your ignorance and shattering your music-lover persona in the process. Open the app, hold it up to the music – and before you know it, you’ll have the tune’s artist, song title and album in the palm of your hand, whether it’s been playing on the radio, TV or elsewhere. It’s no surprise it’s been downloaded more than 1 billion times to date – racking up over 30 billion individual Shazams since its launch. Following the app’s colossal success, Apple bought Shazam in 2018 for an estimated $400 million, stating it was a ‘natural fit’ for Apple Music – and is already used by Apple’s assistant Siri, giving users the answer to the question, “What song is playing?”. 

Using Shazam is such a simple process, you could be forgiven for thinking what’s happening in the background is equally as straightforward… but you’d be wrong. The workings of the app are incredibly complex – first of all, computers do not have an intuitive understanding of music the way humans do. So, how does Shazam manage it? Avery Wang, Shazam’s Chief Scientist, hit upon the idea of creating a unique audio fingerprint for each song in their database. Using data from the most intense moments of a track, a spectrogram is created which plots the three dimensions of frequency vs amplitude vs time. Then, an algorithm selects the plot points that represent the highest energy content – ignoring everything else – and creates a unique signature. It’s thanks to this approach that Shazam works just as well in crowded places, noisy environments and even when a song has been altered in speed.

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We’re no longer bound by traditional outlets for discovering music – and thanks to this app, industry professionals like our own composers at PHMG now have the luxury of uncovering a treasure trove of inspiration wherever they may be.

Shazam allows us all to release our inner musical genius, to access new depths of knowledge and experiences in a heartbeat – and in a time where music follows us almost everywhere, being able to uncover gems to add to our personal playlists… well, it’s magical.