Birthday greeting hidden in a noise-file's spectrogram


John "Control Geek" Huntington's sound-geek friend Jamie made him this awesome birthday message by designing a noisy audio file that would turn into a birthday greeting when it was turned into a spectrogram (Wikipedia: "a time-varying spectral representation (forming an image) that shows how the spectral density of a signal varies with time").

Spectrogram Birthday

(Thanks, John!)