How can computers identify a song?

My Dad’s phone has this brilliant app that can tell you the name of the song when you press a button, even if it only records a tiny clip! How does that work?

mumbuttonThat’s a great question!  It’s almost like there is a musical expert listening to every track and digging through their collection of CDs to find a match.

Every piece of music is different – some are soft with violins, some are loud with guitars.  Some have noisy choruses, others may have gaps.  These different sounds are created by differently-shaped sound waves.

Computers can take all the soundwaves in a song, and make a pattern from them, called a spectrograph – it’s like a musical fingerprint.  Say you’re in a café and the radio plays this cool tune you’ve never heard before.

You click the app and it begins to listen.  The app captures the sound waves and creates a spectrograph – another musical fingerprint – for the clip.  Then it runs this through its enormous catalogue of spectrographs, comparing the sample until it finds a match.

The information is displayed on the phone – often in a matter of seconds.  Spectrographs can be very clever… they can sometimes can even find a match if you sing or hum the track!  Why not give it a try?

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