One year at church camp, the teacher was trying to help a room full of young minds wrap around the concept of God. He began walking us through a mental exercise. He told us to imagine a world in two dimensions. This world was wide and long, but the concept of height was unknown to them. They live their lives not even knowing what they were missing. He then told us to imagine ourselves stepping into this world as a three-dimensional being. These two-dimensional people would only be able to perceive our width and our length. Our height would be inconceivable to them. They would know that there is much more to us than they could comprehend, but would have no way to fully grasp it. I thought it was a great way to introduce the concept. I used it with my kids in our talks about God.
Dolby has recently added a third dimension to home theater. For years, home theater listeners have enjoyed two-dimensional sound in a variety of flavors. Now, all things are new!
Many years ago sound came in one variety: Mono. One channel. Mixing audio was a simple process. In 1903 a British electronics engineer named Dower Blumlein added a huge level of complexity to sound. Legend has it he was watching a movie with his wife when he remarked that a blind person would never know where the actors were positioned on the screen. This apparently bothered him so he got to work on “Binaural Sound.” Many of his patents are still in use today in modern audio production.
In the process of mixing stereo audio a mixing engineer has a way to route audio signals from one place to the other. This eventually allows him/her to determine how much of a particular sound is placed on each of the two channels in a stereo mix. This process allows your brain to process more sounds at a time. In a mono mix your sound can become a bit overwhelming as everything appears to be coming from one location. In a stereo mix, instruments, vocals, and sound effects can be positioned in a stereo spread. This gives the listener a chance to decode the sounds almost individually.
Many people consider Walt Disney to be the father of surround sound. He worked with engineers at the Bell Laboratories to develop a way to mic the music for Fantasia in a manner that would improve the listening experience for the viewer. Fantasia was released with this capability, but only a couple of theaters could afford the Fantasound system needed to play it back correctly. Walt was ahead of his time in the 1940’s.
Dolby took that to the next level in the 1970’s with Dolby Stereo. Their processing in the original Star Wars movie was the real groundbreaker for theatrical surround sound. Lucasfilm developed the THX standard that most theaters use today.
If you look back at how stereo audio was mixed you can get a feel for how most surround sound was mixed. Essentially, a mixing engineer would use a mixing console to route audio signals to a number of different audio channels in order to give the listener a “place” in the two-dimensional soundtrack. This surround sound could be presented to the listener by way of a number of different speaker configurations. These were represented as a series of numbers divided by decimal points. For example, a 5.1 surround system would have left front, center front, right front, left rear, and left front along with one subwoofer. A 7.2 surround system would have the same speakers with the addition of left and right side speakers and an additional subwoofer.
Well, Dolby has done it again. Introducing Atmos. Dolby Atmos has been out in professional theaters for a while now, but has recently come available for home theater. For the listener, Atmos brings a third dimension, height. For the audio mixer Atmos brings an easier way to mix soundtracks.
In a Dolby Atmos enabled theater, there are either speakers installed in the ceiling or the side speakers are enabled to “bounce” sound off of the ceiling. The new technology adds another decimal to the previous surround sound nomenclature. If we add 4 ceiling speakers to the above 7.2 surround system it becomes a 7.2.4 (Won’t you feel smart telling everyone this at your next dinner party?).
The sound is incredible! A movie scene that involves things like rain, birds, airplanes, etc. become very enveloping.
From an audio mixer’s point of view the processing is done digitally. Instead of using a series of pots and faders to route sound to the appropriate channel to give the listener some spatial perspective, the audio is processed in a computer generated virtual three-dimensional space. Each sound is treated as an individual object and can be placed or moved through that space. Of course special software and hardware is required to make this happen, but the time savings quickly pays for the upgrade. Atmos has enjoyed fast adoption by the industry. One of the first commercially available Atmos productions was Disney and Pixar’s “Brave” in 2012. Imagine that. Once again ol’ Walt is innovating surround.
For the installer (that’s me!) this means full Dolby Atmos can be achieved with a number of different configurations. In a smaller room, or with a smaller budget, Atmos can be achieved in a 5.1.2 configuration. If the room and budget allow, a 7.2.4 Atmos system sounds really nice!
I recommend you check out http://www.dolby.com/us/en/find-a-movie-theatre.html for the nearest Atmos enabled theater, pick a good movie, and go experience the third dimension!
Keystone Jack 