When Thomas Edison invented the phonograph he noted that when played backwards, music sounded novel but all together different. Fast forward a hundred years later and experimental musicians began to purposely include backward recordings, or backmasking, on their albums. Artists like the Beatles inserted these clips and teenagers everywhere began searching their record collections for hidden messages. Today every new pop song that comes out is scrutinized in reverse in search of possible satanic references, allegiance to the Illuminati, or any random string of possible words.
Technically backmasking is the process of reversing an audio track and placing it in another track meant to be played forward. When played normally the message will sound like gibberish, but when reversed is clear. Some of the classic examples that follow were intentionally done this way, while other artists contend that if there is any meaning to be found when playing their music backwards it is purely coincidental.
The Beatles were among the first artists to incorporate backmasking into their music. Following rumors that member Paul McCartney had been killed in a car crash and replaced with a lookalike fans scoured their White Album for clues to confirm this. The legend grew as they seemed to find what they were looking for. During the song "I'm So Tired" John Lennon can be heard speaking but not plainly. When played backwards, it sounds like he says "Paul is dead man. Miss him, miss him, miss him." You decide:
YouTube is full of videos purporting to be evidence of unmasked backmasking. While a lot of the 'backwards translations' sound more like gibberish to me (the example that comes to mind being Brittney Spears' "Hit Me Baby One More Time" being "sleep with me I'm not too young" in reverse), we can find among them the classics. Listening to the backmasked tracks is a lot like listening for EVP evidence while ghost hunting. What you hear isn't usual talking or singing. The pronunciations and inflections are skewed, but with a little push (such as including the backward interpretation on screen) listeners may hear alternate messages.
The connection between backmasking and Satanism can be traced back to the grand magician himself, Aleister Crowley, who stated in a 1913 book that those wishing to practice the dark arts would do well to learn to speak backwards. Sixty years later Led Zeppelin guitarist Jimmy Page moved into what used to be Crowley's mansion. Is it a coincidence, then, that the most often cited backmasked message, which also fits into the category of seeming to promote satanic worship, appears in Zeppelin's "Stairway to Heaven?"
Another often cited song when talking about backmasking is Queen's "Another One Bites the Dust." When played in reverse, some say "It's fun to smoke marijuana" can be heard. The band denies an intentional message. This is often cited as an example of phonetic reversal, where a word sounds similar to another word when reversed and similar connections are made by the brain, as with matrixing when looking at photos of "ghosts." Judge for yourself:
The Eagles were also targets of the Christian movement to expose satanic music. When "Hotel California" is played backwards, they claim to hear an allegiance to the devil. Listen to it below and decide:
Did you hear anything like "Satan hears me, he had me believe in him?"
A quick YouTube search for backmasking will turn up these classics, as well as what seems to be every song released by Beyonce, Lady Gaga, Rihanna, Jay-Z, and Nicki Minaj, all who seem to have either sold their soul to the devil and are announcing it to the world or have secretly embedded clues that they are part of the New World Order and the Illuminati. A list of admitted intentional backmasking, sometimes for comedic purposes, can be found here. All the others out there are unintentional, or not being admitted to because of the artists' secret allegiance with the dark powers that be.
Here's one more, just for fun. This YouTube user has taken Nirvana's grunge-ground breaking "Smells Like Teen Spirit" and found an entire song in reverse. I found it uncanny that the listener managed to translate the whole song, with the better part of it sounding like rock song lyrics.