Holophonics is a

binaural recording Binaural recording is a method of Sound recording and reproduction, recording Sound recording, sound that uses two microphones, arranged with the intent to create a Three-dimensional space, 3D stereo sound sensation for the listener of actuall ...

system created by Hugo Zuccarelli that is based on the claim that the human auditory system acts as an

interferometer Interferometry is a technique which uses the '' interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...

. It relies on phase variance, just like

stereophonic sound Stereophonic sound, commonly shortened to stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configurat ...

. The sound characteristics of holophonics are most clearly heard through

headphones Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an ...

, though they can be effectively demonstrated with two-channel stereo speakers, provided that they are phase-coherent. The word "holophonics" is related to "acoustic

hologram Holography is a technique that allows a wavefront to be recorded and later reconstructed. It is best known as a method of generating three-dimensional images, and has a wide range of other uses, including data storage, microscopy, and interf ...

History

Holophonics was created by

Argentine Argentines, Argentinians or Argentineans are people from Argentina. This connection may be residential, legal, historical, or cultural. For most Argentines, several (or all) of these connections exist and are collectively the source of their ...

inventor Hugo Zuccarelli in 1980, during his studies at the Politecnico di Milano university. In 1983, Zuccarelli released a recording entitled ''Zuccarelli Holophonics (The Matchbox Shaker)'' in the United Kingdom (UK) that was produced by

CBS CBS Broadcasting Inc., commonly shortened to CBS (an abbreviation of its original name, Columbia Broadcasting System), is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainme ...

. The recording consisted entirely of short recordings of sounds designed to show off the Holophonics system. These included a shaking matchbox, haircut and blower, bees, balloon, plastic bag, birds, airplanes,

fireworks Fireworks are Explosive, low explosive Pyrotechnics, pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large numbe ...

, thunder and racing cars. In its early years, Holophonics was used by various artists, including

Pink Floyd Pink Floyd are an English Rock music, rock band formed in London in 1965. Gaining an early following as one of the first British psychedelic music, psychedelic groups, they were distinguished by their extended compositions, sonic experiments ...

for '' The Final Cut'',

Roger Waters George Roger Waters (born 6 September 1943) is an English musician and singer-songwriter. In 1965, he co-founded the rock band Pink Floyd as the bassist. Following the departure of the group's main songwriter Syd Barrett in 1968, Waters became ...

solo album, ''

The Pros and Cons of Hitch Hiking ''The Pros and Cons of Hitch Hiking'' is the debut solo studio album by Roger Waters, bassist/songwriter and co-founder of English rock band Pink Floyd; it was released in 1984. The album was certified Gold by the Recording Industry Associati ...

'' and

Psychic TV Psychic TV (aka PTV or Psychick TV or several other aliases) were an English experimental music, experimental video art and music collective, formed by performance artist Genesis P-Orridge and Scottish musician Alex Fergusson (musician), Alex ...

's ''

Dreams Less Sweet ''Dreams Less Sweet'' is the second studio album by English experimental music, experimental band Psychic TV, released in 1983. It was the last Psychic TV album to feature co-founder Peter Christopherson, Peter "Sleazy" Christopherson. Recordi ...

''. The system has been used in film

soundtracks A soundtrack is a recorded audio signal accompanying and synchronised to the images of a book, drama, motion picture, radio program, television program, or video game; colloquially, a commercially released soundtrack album of music as featured ...

, popular music, television and theme parks. Most famous sound effects were recorded in Modena at Umbi's Studios by sound engineer Maurizio Maggi. Holophonic is patented and registered by Umberto Maggi (Italy). Zuccarelli states that the human auditory system is a sound emitter, producing a reference sound that combines with incoming sound to form an interference pattern inside the ear. The nature of this pattern is sensitive to the direction of the incoming sound. According to the hypothesis, the

cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus (cochlea), modiolus. A core component of the cochlea is the organ of Cort ...

detects and analyzes this pattern as if it were an acoustic hologram. The brain then interprets this data and infers the direction of the sound. An article from Zuccarelli presenting this theory was printed in the magazine ''

New Scientist ''New Scientist'' is a popular science magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organ ...

'' in 1983. This article was soon followed by two letters, casting doubt on Zuccarelli's theory and his scientific abilities. To date, there has been no evidence provided that any acoustic emissions are used for sound localization. Holophonics, like binaural recording, instead reproduces the interaural differences (arrival time and amplitude between the ears), as well as rudimentary

head-related transfer function A head-related transfer function (HRTF) is a response that characterizes how an ear receives a sound from a point in space. As sound strikes the listener, the size and shape of the head, ears, ear canal, density of the head, size and shape of n ...

s (HRTF). These create the illusion that sounds produced in the membrane of a speaker emanate from specific directions.

Otoacoustic emissions

While

otoacoustic emission An otoacoustic emission (OAE) is a sound that is generated from within the inner ear. Having been predicted by Austrian astrophysicist Thomas Gold in 1948, its existence was first demonstrated experimentally by British physicist David Kemp in 19 ...

s do exist, there is no evidence to support the assertion that these play a role in sound localization, nor is any mechanism for this "interference" effect claimed by Zuccarelli supported. On the contrary, there is abundant literature proving that properly presented spatial cues via HRTF synthesis (mimicking binaural heads) or binaural recording is adequate to reproduce realistic spatial recordings comparable to real listening, and comparable to the Holophonics demonstrations.Gilkey & Anderson, "Binaural and Spatial Hearing in Real and Virtual Environments"

Recordings released using holophonics

* Pink Floyd, '' The Final Cut'' Harvest/E.M.I, 7243 8 31242 2 0 (1983). * Paul McCartney, " Keep Under Cover", 1983. * Roger Waters, '' The Pros and Cons of Hitchhiking'', Harvest, CDP 7 46029 2 (1984). *

, ''

'', Some Bizzare (1983).

References

{{reflist Argentine inventions Audio engineering Sound recording Mass media technology Sound production technology