Microphone Troublesooting

We have a large number of lecture halls in the institute. Each one has its own audio equipment (public address system). The maintenance system is not on a preventive maintenance basis, but on demand basis. Which means you call a service engineer when the system malfunctions, and he will repair it when he finds time, if he can do it. If he cannot, he calls the manufacturer who will repair it in due course. Minor malfunctions are often neglected. I cannot open up such a system and repair it. I dare not try it too, because it belongs to the institute, and unauthorized people are prohibited from touching the insides of the systems.
I have found methods of addressing two malfunctions of the microphones. I believed I had written about the first one in the past, but a Google search of the blog did not show it. So here it is again.

1. The microphone in one lecture hall in the college was making vibrating noises when I spoke into it. It was quite disturbing. I asked the students if it did the same thing at other times too. They said it did. So the fault was not with my speech. I looked at it and thought that there must be something in the upper end which picked up audio and vibrated. I also remembered that posh microphones had some sort of cloth on the surface - felt, duster cloth or sponge. This one was all metal. So I took out my folded handkerchief, wrapped it around the upper end and spoke into it. The students kept watching. This was probably more entertaining than the drab lecture on some gynecological topic. When I spoke, the audio came out perfect. The students grinned all over their faces. I hope they told the subsequent teachers how to address that issue.
2. The microphone in our own seminar hall does something funny. When the audio volume is increased, and one speaks into the microphone, it makes a keening noise that raises goosebumps on sensitive people, and irritates everyone. I had heard somewhere that air currents from fans can cause this effect. The seminar was not being presented well because of this disturbance. Then I had an idea. "Hold the microphone upside down and then speak into it" I said. My theory was that air currents would not enter it if it was directed towards the floor. The resident was reluctant to do so, probably because it would look funny. It must have looked funny to others, because many people laughed and some people even took out their phones and snapped pictures. I had to scold them not to embarrass the speaker, and even threaten to confiscate the phone of a senior faculty. That stopped the merriment. But the main thing was that it actually worked. I hope this post helps when people face this problem. I made an illustration to show how it was, rather than post one of the pictures people shot of the resident doctor. I could not embarrass that resident further, especially when the original idea was mine, not that of the resident. My illustration is shown below. It was a cordless microphone.