DOOM is a game of many secrets. The fast-paced shooter is filled to the brim with nostalgia-laden easter eggs to discover, catering well to its demographic. It’s no surprise that its soundtrack is bursting with secrets as well, this time of the spectrogram variety, according to eagle-eyed fan TomButcher. It’s no surprise that its soundtrack is bursting with secrets as well A spectrogram is the visualization of the frequencies of sound. While usually acting as most visualizers do—giving the listener some pretty colors to look at while enjoying a song or album—some musicians, like Aphex Twin, have slipped in eerie…