Mathematics
Fast Fourier Transform (FFT)
Quick fact
The FFT reduces the work of computing N frequency components from about N² operations to N log N operations—for a 1-second audio clip with 44,100 samples, that's roughly 600,000 times fewer multiplications.
Why this is interesting
You use the Fast Fourier Transform dozens of times a day—every time you stream a song, take a photo, or make a phone call. But how does your device separate a jumble of noise into beautiful individual frequencies so quickly?