Backmasking

Backmasking (also known as backward masking) is a recording technique in which a sound or message is recorded backward onto a track that is meant to be played forward. Backmasking is a deliberate process, whereas a message found through phonetic reversal may be unintentional.

Backmasking was popularized by The Beatles, who used backward vocals and instrumentation on their 1966 album Revolver. Artists have since used backmasking for artistic, comedic, and satiric effect, on both analog and digital recordings. The technique has also been used to censor words or phrases for "clean" releases of songs.

In 1877 Thomas Edison invented the phonograph, a device that allowed sound to be recorded and reproduced on a rotating cylinder with a stylus (or "needle") attached to a diaphragm mounted at the narrow end of a horn.

In addition to recreating recorded sounds by placing the stylus on the cylinder or disc and rotating it in the same direction as during the recording, one could hear different sounds by rotating the cylinder or disc backwards. In 1878 Edison noted that, when played backwards, "the song is still melodious in many cases, and some of the strains are sweet and novel, but altogether different from the song reproduced in the right way".

The 1950s saw the development of musique concrète, an avant-garde form of electronic music which involves editing together fragments of natural and industrial sounds, and the concurrent spread of the use of tape recorders in recording studios. These two trends led to tape music compositions, composed on tape using techniques including reverse tape effects.

The Beatles, who incorporated the techniques of concrète into their recordings, were responsible for popularizing the concept of backmasking. Singer John Lennon and producer George Martin both claim they discovered the backward recording technique during the recording of 1966's Revolver; specifically the album tracks "Tomorrow Never Knows" and "I'm Only Sleeping," and the single "Rain".

Backmasking has been a controversial topic in the United States since the 1980s, when allegations from Christian groups of its use for Satanic purposes were made against prominent rock musicians, leading to record-burning protests and proposed anti-backmasking legislation by state and federal governments. Whether backmasked messages exist is in debate, as is whether backmasking can be used subliminally to affect listeners.

Artists who have been accused of backmasking include Led Zeppelin, The Beatles, Pink Floyd, Electric Light Orchestra, Queen, Styx, AC/DC, Judas Priest, The Eagles, The Rolling Stones, Jefferson Starship, Black Oak Arkansas, Rush, Britney Spears, and Eminem.