When Thomas Edison invented the first wax cylinder phonograph in 1877, his recordings contained a lot of hiss, crackle and noise. Improvements in recording technology were made through the early decades of the 20th century, and by the late 1950s, techniques had been developed to both record and re-play music and other sounds more faithfully and in stereo - that is with two channels, one for each of our ears.

Audio engineers and enthusiasts have noticed, however, that the stereo recordings that have been commonplace never seem to fully reproduce sounds absolutely authentically. A lot of this seems to stem from the fact that "real" sound generates knowledge of its location within the listener, and it does not merely emanate from two places on either side of our heads.

The 1970s saw experimentation with "quadraphonic" sound - sound that was projected in four directions, and this "surround sound" concept has been further refined with the creation of 5.1 surround sound. 5.1 uses 5 channels (left, right, front, back and center), plus an additional subwoofer channel of low frequency sounds to add more realism and allow the listener to "feel" the sounds.

High quality sound recordings are generally made today by using "binatural" recording techniques - a two-track recorder is connected to two microphones that are contained within a fuzzy "head". The dummy head contains ears, sinus cavities and other similarities to a human head. This means that the microphones "hear" and therefore record sound more realistically - much more like a human head hears and might record sound if we had digital recording technology inputs and outputs.

But there is another kind of sound recording that is even more realistic - Holophonic Sound. Developed in the 1980s by Hugo Zuccarelli, Holophonic Sound uses the same "multiple exposure" premise as that used to create holographic images ("holograms"). Holophonic Sound is produced by recording the interference pattern generated when the original recorded signal is combined with an inaudible digital reference signal. The recorded sound produced is so realistic, some people claim they can smell sulphur when they listen to a holophonic recording of someone striking a match! It appears that Holophonic Sound waves stimulate our brains to reproduce very realistic and truly three dimensional sound within us, thereby stimulating other corresponding responses that our brains expect to accompany the sound, (like scents or other sensations). Even more interesting is the fact that researchers report that some hearing impaired people can "hear" Holophonic Sound - again because it stimulates their brains even though their audio receiver mechanisms are not working properly.

Holophonic Sound is not ready for your home theatre system yet - it is best heard in headphones, or through use of specially designed speakers. It is also being used by a growing number of professional recordists and sound designers for broadcast, film and miltimedia applications. The Dimension Sound Effects Library, now being distributed by Sound Ideas, is the world's first and only Holophonic sound effects collection.