Situation #2 — The Product Demo Shot:
This time our speaker is demonstrating a product on a table. Before you decide what type of microphone to use, stop and think for a moment. Does this product make any sound at all when demonstrated? If so, how loud is it?
Do you want the sound to be part of the demonstration? If the product makes little or no noise (like a personal computer, for instance), your best bet is probably to put a lavalier mic on the speaker’s clothing in a spot where it will not be disturbed by his movements.
If the product is a food processor, though, your only chance is to use the lavalier or a shotgun to pick up the first part of the demo (before the product is turned on), and then record the rest of the demo without any narration — just the sound of the unit working. Have the speaker do a voice-over without the machine on, which you can dub in later.
Otherwise, you’ll have to use a shotgun mic positioned no more than a foot away from the speaker’s mouth and perpendicular to the food processor for minimal noise pickup. If the product is very small and you have to pick up its sound (such as that of a digital watch alarm beeping), you will need to use a second mic positioned close to it, or else a shotgun a few inches away from it.
Situation #3 — The Panel Discussion Shot:
Here, your assignment is to tape a panel discussion before a live audience. Let’s say that there are five people on the panel, and you also wish to pick up the questions and comments of the audience.
You will be operating the camera yourself, so all the microphones will be on at all times to ensure that no comments are missed. How many mics you use on the panel depends largely on how closely together they are seated — you may be able to pair people up and use one microphone for each pair.
Keep in mind that microphone positioning has a significant effect on sound quality, however. The rule for this situation is widely known, and you would do well to keep it in mind:
The 3-to-1 Rule: The distance between open microphones should be at least three times the distance from each microphone to the nearest talker.
For example, if you place a microphone one foot in front of each talker, the mics should be at least three feet apart form each other. Placing the mics closer together will result in a hollow, “tin can” sound, caused by phase cancellation.
If it’s convenient to have panel members positioned in pairs as mentioned above, you could separate each pair by a distance greater than three feet, allowing the microphones to be further away from each pair of talkers.
The best solution would be to turn off microphones that are not being addressed, which would keep the number of open microphones to a minimum and make the distance between mics less critical. This is easily achieved by an engineer or an automixer.