Practical Sound Pickup

We have looked at typical methods of mounting and positioning microphones. What are their advantages and limitations in practice?

Local sound pickup

• Personal microphone.Simple to use, just clip the miniature mike onto the clothing. (Remember to retrieve it at the end of the session!) There are drawbacks when anyone thumps their chest (many do!), covers over the mike, or has ‘noisy clothing‘. Position the mike to suit the wearer’s probable head position, to avoid sound coming and going as they turn the head.

The long cable from the clip-mike to the audio equipment can be a problem. If someone moves around, they can feel tethered or get it trapped en route. Plugged into a pocket transmitter instead, it becomes a wireless mike, giving considerable freedom of movement. But this more expensive solution is susceptible to fading and interference.

• Desk microphones are fine, as long as people do not rustle papers or thump the table — or turn away from them.

• Stand mikes are liable to be moved, kicked or displaced, but are valuable for localized pickup.

• A hand microphone (baton mike)is excellent in the right hands, but too easily misused and badly positioned.

• A slung mike (hanging mike) works well for stationary sound sources, and actors who hit their floor marks.

• A pressure zone microphone (PZM) is easily attached to a nearby surface, but may pick up unwanted noise and reflected sounds.

• A shotgun or rifle mike, when correctly directed, is great at picking out a source, and excluding others nearby.

• A small sound boom is best considered as a movable suspended mike. Following action by moving its tripod is hazardous!

Using the sound boom

The large sound boom provides the most flexible method of mike placement.

But it is costly, relatively bulky, and needs a skilled operator.

The mike can be turned and tilted towards a speaker, favoring a weak voice, and reducing the prominence of a strong one. It can be positioned to avoid sound reflections from nearby walls.

The boom can follow a moving person over an appreciable area, but it needs to be correctly located for the action. So when planning the show it’s wise to ask:

• Can the boom reach the action? (Not too close or distant?)

• Is it in the best position to cover all the action?

• Is there room for the boom arm to swing, and the perambulator base to maneuver?

• Can one sound boom cover all the action? It may be necessary to track or reposition the boom, move people closer together, or pause while the boom swings to a new action area. (Supplementary mikes or a second boom needed?)

Sound boom coverage

The effective length of the boom arm can be changed, and its angle tilted, to suit variations in the subject distance and height.

The sound boom can swing over a wide arc (360° max.), and tilt vertically over some 20°, enabling it to follow sound within a considerable area.

A central boom position enables it to cover the acting area most efficiently.