PART 5 Recording and Editing the Production FIGURE 15.27 A wireless (radio) belt pack transmitter and receiver. A lavalier microphone can be plugged into the transmitter. (Photo courtesy of Audio- Technica) FIGURE 15.28 Wireless receivers can be located on a camera. In this situation, the interviewer is using a handheld wireless. (Photo courtesy of Sennheiser) FIGURE 15.29 Any type of microphone can become a wire- less microphone if some type of wireless plug-on transmitter is used. This transmitter converts a dynamic or condenser microphone to wireless, transmitting the signal back to a receiver. (Photo courtesy of Audio-Technica) 254 If two or more wireless microphones are being used in an area, it is advis- able to set them to different RF channels to avoid interference. When working near large metal structures, there can be difficulties with RF dead spots, fading, distortion, or interference. Diversity of reception--using multiple antennas--has improved this situation, but it is still cause for some concern. Hidden Mics When other methods of sound pickup are difficult, a hidden microphone may be the best solution to the problem. Mics can be concealed among a bunch of flowers on a table, behind props, in a piece of furniture, and so on. However, hidden mics do have limitations. Although the mic can be hidden, the cable must not be seen and/or the transmitter must be out of sight. Sound quality may also be affected by nearby reflecting or absorbing surfaces. Because the microphone covers a fixed localized area, the talent has to be relied on to play to the mic and not speak off-mic. CONTROLLING DYNAMICS Dynamic Range FIGURE 15.30 It is important to ensure that the batteries in the transmitter, and possibly the receiver, are at full capacity at the begin- ning of a program. The transmitters are usually clipped to the back of the talent. (Photo courtesy of Sennheiser) Everyday sounds can cover a considerable volume range. Fortunately, our ears are able to readjust to an astonishing extent to cope with these variations. But audio systems do not have this ability. If audio signals are larger than the system can accept, they will overload it and become badly distorted. If, on the other hand, sounds are too weak, they get lost in general background noise. In order to reproduce audio clearly, with fidelity, it must be kept within the system's limits. A lot of sounds pose no problems at all. They don't get particularly soft or loud; that is, they do not have a wide dynamic range. When recording sounds of this type, there is little need to alter the gain (amplification) of the system once it has been set to an appropriate "average" position.