Since then scientists have battled to recognise specific aspects of a song, such as its tempo, key, harmony, rhythm, instrumentation, or even just its genre, by analyzing its audio content. Starting in 2004, this battle has been formalised into an annual competition called MIREX. In each round of MIREX, competitors submit their programs to a carefully controlled competition server, where each program is run on the same set of tracks. The winner is the one whose results agree most closely with a matching set of human judgements. But gathering human opinions about very specific aspects of large numbers of songs isn’t easy. You need to find people with a keen interest in music, and ideally some musical expertise. You need to persuade them to answer questions that can seem obvious to them (even though they are still difficult for a computer). Finally you need to have enough helpers to allow for the fact that some interesting musical questions can have more than one ‘right’ answer.
We’ve been thrilled with the all support we’ve been getting from users who are helping us rate the tempo of music tracks in our Speedo experiment, thanks! Now we’d like to ask you to help us with another fun music experiment for a new project called Audio Flowers. We are currently doing some research into new techniques to measure structural change (or “complexity”) in rhythm, harmony and timbre directly from mp3 files. The measurements we take from a song are then summarised to produce a little image: an Audio Flower like the one below.
That’s why at Last.fm we’ve programmed our computers to listen to music. We fed them around 15,000 tracks from the UK singles charts between 1960 and 2008 and discovered some fascinating results we’d like to share with you. It all starts with the discovery that just before the middle of the 70s something in the data changed…