Write 3 Articles About Public Address Systems

I need 3 articles of around 500 words each written about public address systems. To do this you will need to have a working knowledge of PA systems. Please don't bid if you don't understand them. The titles will be: -PA System Basics. This will describe PA systems from simple vocal PA's up to concert systems. It should include a number of simple schematic diagrams. -PA System Safety Will include things such as tripping hazards, electrical hazards, noise etc. -Choosing the Right Microphone for Your PA System. Will talk about the main types of micrphones & which is best for different applications.