Another kind of mike that allows for invisible audio recording is the boundary microphone. Also known as a PZM (pressure zone microphone), the boundary mike is unconventional in that it lays on a table or floor (or attaches to a wall) and effectively uses the entire surface that it rests on for pickup.
Boundary microphones are excellent at picking up large groups of people, background ambience and crowd noises (applause, laughter, etc.) in a non-intrusive or visible manner. On the other hand, these mikes also excel at picking up noisy bystanders, air-conditioning rattles and the hum of fluorescent lights. Though you can't use pressure zone microphones in every situation, they are valuable when recording projects such as corporate meetings, a panel of speakers or courtroom video. By laying one or two microphones on a conference table or desk, and framing the shot properly, you can capture clear audio from a number of subjects without ruining the aesthetics of the image.

You may find yourself in a situation that calls for hiding a mike on something other than a table or person. Get creative. Is there a plant or vase on the set that would hold a mike? How about the edge of a picture frame or door? All of these are good options for hiding a lav. Run any hard wires under carpets and along furniture legs. In an outdoor setting, try a tree limb, down spouting or a fence post for supporting a boom microphone. Try using some sand on the beach to conceal wiring. The possibilities are only limited by your imagination.
Recording good sound for your video doesn't necessarily mean showing the mike. Next time you shoot, evaluate whether the mike should be heard and not seen, then use the tools and tips in this article to get great sound without having those unsightly microphones clutter up your shot.