Sound can be enjoyable if it is played in music or if the voice of a loved one. Sound can also be annoying and it can be torture. In fact sound has been used as a method of interrogative torture in the past. For an animal, which is a prey of another the ability to remain quiet is one of the keys to life. For the predator the ability to hear determines if he will eat or go hungry for the night.

Sound can be something of life and death in the real world. Sound can warn us of impending problems, like a squeaky wheel which is not properly lubricated which will soon fail or an engine making noise which needs some oil added to prevent excessive wear and eventual failure.

In warfare machinery makes noise and if the enemy hears it before you see them, chances are they are already setting up their sites to eliminate you and your comrades as a potential threat. In other words they intend to kill you before you see them and attack. Soon we will be able to cloak sound, which will assist us in getting a good night sleep, hiding from enemies and prevent airports from dangerous noise abatement procedures. How so you ask?

Well there are many ways, such a noise cancellation techniques, sound-proofing and/or honey comb capture. As civilization population get denser and aircraft become larger with more power, sound will become even more critical. Sound is an industry that will certainly be heard or not heard in the future, depending on who you listen too. Think on this in 2006.