Audio is one of those things that can make or break an experience, whereas the visual has somewhat stayed the same over the last few years, audio is currently in a state of evolution. It all started with monaural in the days of the phonograph; then there was stereophonic. In the century following the advent of more theatrical sound. Last but not least, but much more recently, you have audio experiences that aim to create or emulate 3-dimensional spaces. These different flavors consequently aimed at enhancing our sound in different ways.
First There Was One
Mono is just one channel; the best example is when listening to a track via headphones. What you hear in both ears during playback is identical, and the experience is often flat. For some experiences, this may be what the end goal is, but it does not offer much in the way of specifically discerning characteristics of the source.
Then There Was Two
Stereo sound is two channels together that often make for a much more vibrant experience. For example, in music, you can have instruments spread across the two channels to give the illusion of depths and direction.
The More The Merrier
Surround is composed of multiple channels of audio positioned around the listener to further enrich the experience. A prime example would be in movie theaters or home theaters where you can hear a car exploding across the screen in front of you as listen to it fly through the air all the same.
More Than Just Sound
Binaural and 3D Sound are those that aim to recreate experiences in 3-dimensional space. The first of the two is much in the way of how we naturally hear the world around us whereas the latter is similar to that of its visual counterpart, VR or virtual reality.
The Difference Between Mono, Stereo, Surround, Binaural and 3D Soundis not necessarily the experiences they aim to create but instead how one produces them in the first. I would not blame you if you assumed that you just add more microphones, and you would be right, sort of, because for the second to last of them you need unique microphones that “listen” much like our ears.
The technique used in this case is often referred to as “dummy head recording,” where the recording engineer uses a sort of mannequin head with ear-like microphones to record sound. After which, playback is best heard through headphones where you can hear from the right perspective of the source or location of the “dummy.”
The artist Beck some time ago took this to the next level in a VR experience posted online. Worth a look and the dummy recording head used possessed an array of ears all around it.
It really goes to show you that the way we hear is special and reproducing isn’t always as comfortable or elegant as other methods we use every day.