Spatial sound is a very important item in Holographic apps. Everything we do in life makes a sound. Every sound we hear has a source. There is no such thing as ambient sound in the real world.

This is kind of strange if you think about it. For decades, we have been trained by television and movies to expect music and ambient noises to be around us. However, in reality, this is never the case. Every noise comes from somewhere; every noise has a source you can point at. These sources might be hidden, so they are not obvious. They might be distributed across a room, so you are tempted to believe the sound is ambient, or they might be so loud that it seems the sound is coming from all directions, but you know as well as I do that this is not true. There is a source, always. So, why did we invent this crazy notion of ambient sound?

The answer to that question is, of course, lack of technology. When we talked about HRTF in previous parts of this chapter, you learned that you cannot...