As we've said soundfield systems basically consist of some kind of microphone that's worn by the teacher, and then an amplifier and one or more speakers that are fitted around the room to distribute the sound evenly. [Teacher]"Can I just ask what does the teacher's microphone look like?" I have some pictures so I'll show you. They vary. Through the history of soundfields people have used different types of microphones. Early systems were always head-worn microphones, which is technically a really good way of doing it, but very few people like wearing head-worn microphones. So a lot of microphones now are worn round the neck and that's the easy way of doing it. Generally with most systems you do need a fairly close microphone. To get the mic close to the mouth is quite important.