I’ve noticed, as a year long commuter train rider, than conductors as a rule like to be loud in every thing they do.
One way they’re very successful at this is to blow into the damn mic right before they make any announcement.
Is there any reason to blow into the damn mic, other than trying to hurt people’s eardrums? My training as a DJ taught me to talk across microphones, rather than directly into them, specifically to avoid the sonic blast it can cause.
They do to cause the sonic blast. It’s a quick and dirty way to hear if you’re “on”. (Is this thing on?)
At least, this is the only even remotely legitimate reason. It’s quite possible that many people do it just because they’ve seen other people do it, and think that it’s the way you’re supposed to do it.
I don’t understand what you mean by ‘across.’ Can you explain it? This knowledge will undoubtedly come in handy someday.
Folks blow into microphones to determine whether they are operational.
According to Wayne’s World, however, roadies determine whether microphones are operational by repeating “sibilance, sibilance.”
Blowing is something you can’t hear inside your head like talking, so if a mic is on with low volume, you’ll hear the blowing noise amplified.
At least, that’s why I do it.
If you speak, or sing, directly into a microphone, the movement of air caused by "T"s and "P"s and "K"s - the “plosive” sounds - will cause an irritating popping due to excessive movement of the diaphram or coil of mic. Condensor-type mics (expensive ones) are even more prone to this problem.
Experienced singers know this and either avoid singing directly into a mic - across it - or will direct their voices into a mic at certain times, but are aware of the plosives and move the mic or pull away from it to avoid the popping.
You can see them doing this, especially when they are hand-holding a mic.
A good singer will “play” a mic as a musical instrument.
If you see any singer, and even speakers, in a recording session in a studio, you will invariable see a round fabric disc, about 4" in diameter, placed between the mic and the singer’s mouth. This is a “pop filter” and cuts down on the rapid movement of air that causes the popping sound. The fabric is very similar to nylon stockings.
Blowing into mics is frowned upon, to put it mildly, by recording engineers. Some of the very best mics in the world are still old “Ribbon” microphones. A blast of air can utterly destroy those.
I always used to use “test…test…check…check…cash…cash…” 
Sorry, they are usually 6-8" in diamter.
To the OP, I dunno why people do this. Something they’ve seen on TV or heard on the radio, I guess.
[minor hijack]What tickles me is the scene in every movie that shows anybody talking into a PA system mic, if the person that does it is a nerd, or nervous, the PA system always gives a little squeal of feedback…[/mh]
Blowing or tapping on the mic are a good way to test if they’re on. Just talking into it isn’t as effective since you mind automatically cancels out hearing your own voice.
I was always taught to scratch the mic. That way you’re not stressing the diaphram and you get to hear the scratch as you’re not producing any sound from your mouth.
Blowing into a mic. in a studio will get you a reprimand from the tech.
Blowing into a mic. in a pub will get you a foul look from the audience and make you look like an idiot.
It’s a good way of destroying microphones. And yes, you should talk directly into the mic. Experienced users know how to avoid the P, B, T, S that make for bad sound.
The best way to determine if it’s on is to tap - gently - on the mic. Blowing into it can destroy very expensive equipment.
“Sibilance” is when the soft ‘s’ sound comes out of the speakers sounding like static. Some sound techs say it because it starts with S and lets them tune the mixers so that an ‘s’ sounds right.
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So why do actors and many other “professional” speakers, who use microphones everyday in their job, lean down and talk directly into a mic during award ceremonies?
Or don’t they trust the sound engineers to compensate for them?
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I do it to clear away the last user’s brine shrimp.
Because when you are a performer or professional who uses a sound system a lot, you are accustomed to having floor monitors aimed at you , and away from the audience. You get to hear your own sound coming back at you.
Having shot the Emmy Awards and the Hispanic Heritage Awards, as well as other awards shows, I can tell you from firsthand experience that there are no floor monitors used on those shows. They mess up the stage look. So, those folks who are used to audio monitor returned to their ears while they are live, are bereft during an awards ceremony. Leaning down makes them feel as though they will be heard. Also, they may lean down for the first few seconds as they speak- and are listening intently at the same time- then, once aware they can hear a bit of themselves from the house system, they may stand up again.
They would rather protect themselves than believe that the mic is picking them up if they cannot hear themselves.
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