Dolby has an amazing joke from 'Spinal Tap' memorialized in its new headquarters

"This is Spinal Tap" is one of the funniest movies of all time.

It's a parody of a heavy metal band "rockumentary" from the 1980s, and was released in 1984. The premise is that the filmmakers are following a successful group, Spinal Tap, except the tour turns out to be a rolling disaster, with sparse crowds and epic failures throughout. Along the way, Christopher Guest and crew poke fun at every 1970s rock and roll cliche imaginable, and the movie's full of now-classic lines like the one about the amps that go to 11. Even if you don't really know or care about heavy metal or rock movies, it's worth watching.

One of the classic scenes in the movie is this one, where the lead singer's girlfriend is trying to explain why the new album isn't selling well, and criticizes how it was mixed, saying "You don't do heavy metal in Dobly."

She means "Dolby," a noise-reduction technique that was used on consumer stereo equipment in that era. The guitarist, Nigel Tufnel, takes her to task.

Flash forward 31 years. Dolby is still a going concern, and makes audio technology used in everything from PCs to movie theaters. Today, it showed reporters its new headquarters in San Francisco. There, it has memorialized the joke forever:

Matt Weinberger/Business Insider

The best part? Apparently employees write in all the time saying "Nice piece, but you misspelled 'Dolby.'"