You would have a binaural recording that works perfectly for you when played back over headphones. If you placed tiny microphones inside your ears and captured the signals, they would include the effect of your HRTF. As part of our hearing system, our brains have learned to decode all those changes to decipher where the sound likely originated in the space around us. Those physical interactions impact the levels, timing, and phase relationships of the different frequency content of the sounds we hear. Our head-related transfer function ( HRTF) refers to the effect our shoulders, head, and outer ears have on sound waves coming from different sources before they encounter our eardrums. We only have two ears, but we can differentiate between sounds coming from in front and from behind, as well as left from right, above, and below without even moving our heads. This was upgraded in 1987, with Dolby Pro Logic for a total of four audio channels. How did surround sound arrive at home?Īfter some attempts to push 4-channel quadraphonic sound equipment into the home market in the 1970s, surround sound really arrived in living rooms in 1982 with the introduction of 3-channel Dolby Surround. DTS produced a competing product in its DTS:X. Upping the ante once more, the Dolby Atmos immersive sound system was unveiled in 2012, which added height information via ceiling-mounted speakers. Other companies, such as Digital Theater Systems (DTS) and Sony, brought their own technologies to the surround sound game. Over that period it iterated from the 4-channel Dolby SR, to the 6.1/7.1 channel Dolby Digital Surround EX. Starting with the release of Dolby Stereo in 1976, and no doubt helped massively by the success of Star Wars (1977), Dolby drove the mass adoption of surround sound in theaters throughout the 1980s and 1990s. Consequently, film surround sound died out completely by the 1960s. Although that system was impressive, the concept proved too complex and expensive for most theaters. The full 54-speaker setup was only installed in two theaters. For the release of the studio’s revolutionary animated film Fantasia in 1940, it unveiled a multichannel sound system called Fantasound. Among its many technical innovation credits, The Walt Disney Company claims the first documented commercial use of surround sound in film.

Sony dolby surround sound system