May 20, 2019 - Robert John Hadfield

Feedback - The Kind To Avoid

Holding The Microphone Close

 

Recently I attended a panel at a pop culture event. There were a few speakers there and an audience of a few hundred people. There was no podium in place so each speaker held a microphone in their hand.

I have been involved in audio work, both studio and live, for almost three decades. In that time I have seen one pattern over and over when it comes to hand-held microphones, and this situation was no different. When most people hear their voice coming through the PA they immediately move the microphone away from their mouth.

It’s a strange reaction considering the fact that a microphone is supposed to do that. But for some reason people seem to be bothered hearing their own voice through a PA system. When they first speak into the microphone and hear themselves they will often let out a small gasp, say, “whoa” and even recoil a little bit. You’ve probably seen something like this yourself in a live setting with an inexperienced speaker. And even if they don’t gasp, you will notice them move the microphone further and further away from their mouth during the course of their presentation.

Many people think their voice is loud enough to be heard throughout the room; they are almost always wrong. Even in relatively small settings of 20 to 30 people, a microphone is a good idea. It gives a little boost to the sound and people will miss if you take it away. I was in a setting once where the speaker said, “I don’t think this is really doing any good” and then set the microphone down. Before her next sentence was even finished, members of the audience called out for her to pick it back up.

A headset or lapel microphone is preferable in a live speaking setting because the speaker cannot move the microphone away. This allows the sound engineers, not the speaker, to manage the sound and keep the volume at such a level that people can hear effectively.

Of course that’s not always possible, so the hand-held microphone has to do.

As the speaker moves the microphone further and further away from his mouth, the person running the PA has to turn the volume up more and more to compensate.

There are two problems when this starts happening.

  1. When a person moves a hand-held microphone further away from their mouth, their voice loses body and starts to sound tinny.
  2. The louder you turn up the microphone, the more chance there is for feedback.

In a business setting we have positioned the word “feedback” to mean something very positive. But in the world of audio production, feedback is generally a bad thing. When you hear that high-pitched screechy sound come from a microphone, that’s feedback. In this case it is specifically known as “looped feedback,” and it is one of the most unpleasant sounds in the modern world – especially when it is really high pitched.

What generates this type of feedback is pretty simple.  It is caused by the equipment and environment itself. In a live setting with a PA system there is an input and an output. The microphone is the input and the speakers are the output. It is a little known fact that those two things are somewhat interchangeable too. If a speaker is plugged into a microphone connection, you can actually speak into it and it will act like a microphone. The same is true for a microphone, if you plug it into a speaker output, you will hear sound come from the microphone. Of course you can easily destroy both things when you do this, but the point is they work on similar principles.

When you speak into a microhphone (the input), your voice is amplified and then sent through a speaker (the output). Because the microphone and the speaker are in the same vicinity in a live setting, a loop can start. What is the loop? The sound coming out of the speaker goes back into the microphone which then comes back out of the speaker and back into the microphone, and on and on. Depending on the room and the equipment itself, certain frequencies take over and that is what causes the shrill noise we have all heard that causes us to cover our ears.

There are only a few ways to deal with looped feedback. You can change proximity by moving the microphone away from the speaker, or you can turn down the volume. There are also some pieces of equipment today that immediately detect the feedback frequency and then specifically filter that frequency out of the system. But equipment of that nature is really intended to be a secondary tool when the proximity and volume aren’t controlling the feedback effectively.

So what does this have to do with a hand-held microphone?

As I said before, it is a natural tendency for most people to immediately move the microphone away from their mouth when they hear their voice. This forces the sound man to turn the volume up, which naturally leads the person to move the microphone even further away from their mouth.

You can see where this is going.

As the volume is increased, it isn’t long before we hear that shrill noise that we all hate. And as soon as that happens, the person holding the microphone becomes deathly afraid of it. And if it wasn’t difficult enough to get them to hold the microphone close to their mouth before, now they won’t even come close.

The irony is fascinating. That horrible feedback noise that frightens the person speaking, is actually the result of the person’s fear of speaking into the microphone. If the person holding the microphone would keep it close to their mouth, the sound guy can keep the volume lower which keeps feedback down.

It’s one of those amazing situations where someone causes a problem by trying to avoid it.











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