Using Microphones In Theatrical Environments

A primer on key considerations for effective stage mic’ing.

In theater production, there are hundreds of thousands of minutes—countless hours of rehearsals and meetings, late-night artistic brainstorms and problem-solving sessions—that lead to one moment. When the stage is set, the orchestra is tuned, the lights dim and the curtain rises, everything must work flawlessly.

From Broadway to small community stages, from large productions to small ones, the theater experience relies on great sound. That, of course, includes considering the physical theater environment and its acoustic qualities in designing a sound-reinforcement system. Proper microphone selection and placement in theater applications is an area that can dramatically improve and reinforce the impact of the action and emotion on the stage.

Microphone Overview

Two of the most common types of microphones used in professional audio today are dynamic microphones and condenser microphones. Because of their design, some condenser microphones can be considerably more expensive than dynamic microphones are. Condensers are also more fragile than their dynamic counterparts are. Condensers can be damaged by temperature, humidity and rough handling.

Those considerations notwithstanding, condensers provide a great advantage over dynamics in theater applications for a couple of reasons. First, they can be made much smaller than dynamics, making them easier to mount on or hide in wigs and costumes. Second, they generally have wider frequency response and higher sensitivity, making them better for use in critical sound-reinforcement applications and better for overhead or boundary microphone techniques in which microphones are placed much farther from the performers.

Choosing the proper microphone for any given application can also be based on several other factors; they include price, quality and, especially in theater, physical size and color. Whichever microphone is chosen, it is the first step toward creating an effective sound system.

The goal of any sound-reinforcement system is to project the program material to the audience in a manner that allows the person farthest away from the performance area to hear sufficiently. An efficient system will allow enough amplification to occur before feedback is a problem. You often might hear the term “gain before feedback,” which refers to this principle. Audio feedback can be devastating to any production, and it can severely distract the audience and the talent. That’s not even to mention the damage it can do to the sound system and your hearing.

In many theater shows, it is not practical to use a typical handheld vocal microphone; instead, most will use either a lavalier or a headset microphone. Those microphone types allow you to “close mic” the performers. After all, the closer you can get the microphone to the sound source, the better the audio quality will be. Most modern lavalier and headset designs are lightweight and discreet. Both do an excellent job of increasing potential gain before feedback.

Without question, wireless microphones have become the “go-to” choice for theater productions. Wireless mics provide better audio isolation and sound quality that is more consistent. Because wireless allows microphones to be closer to the talent, they are perfect for capturing a performer’s delicate vocal expression.

Lavalier microphones are composed of small elements, usually condenser, de signed to be mounted via clip or pin to clothing. In theater, they are generally connected to a wireless microphone bodypack. The small design of these mics makes them inconspicuous enough to be used in TV broadcast, video production and, of course, theater.

Lavaliers are often available in several colors, such as black, white, cocoa and tan. In theater, lavaliers are often concealed in a wig, hat or costume. Sometimes, lavaliers are attached directly to the actor by using medical tape. It is important to consider lavaliers mics that have been tested for durability against cable failure, given that cables are exposed to significant wear and tear. Also, using a lavalier mic that has been designed to reduce damage caused by sweat is a long-term advantage. Lavaliers allow you to place the mic much closer to the actor’s mouth, increasing gain before feedback and minimizing background noise. The goal is to amplify the actor’s voice and minimize pickup of room noise, stage vibrations and other unwanted sounds. When used with wireless systems, lavaliers give performers almost unlimited mobility. Additionally, if the wireless bodypack is attached to the actor using a mic belt, it can enable fast costume changes while keeping the audio consistent.

Omnidirectional-pattern lavalier mics dominate the theater industry. Although there are some cases in which cardioid-pattern mics can be useful in high-volume environments, omnidirectional condensers remain the most popular choice for theater. Omnidirectional mics have a more natural balanced sound than cardioid mics do, and they are less affected by wind/breath noise than their cardioid counterparts are.

An actor who moves around a lot will have minimal volume fluctuations when using an omnidirectional mic as compared to a directional mic. Omnidirectional microphones do not exhibit the proximity effect, which means the bass does not increase as the mic is moved closer to the audio source; this reduces having to cut low-frequency response at the mixer.

Another reason that omnidirectional mics can be advantageous in theaters is that the frequency response of the mic stays consistent, even if the sound source is off axis or the mic is in an unusual position. This attribute is quite important, given that mic technique in theater productions involves the creative positioning of the microphone on a performer’s skin or in a wig or costume.

Wireless Microphone Systems

To achieve the ultimate in actor mobility, as well as to maintain the highest potential gain before feedback, wireless microphones are the best choice. In fact, the earliest use cases of wireless microphones were based on the very needs that theater presents. Without wireless lavalier microphones in larger productions, movement would be restricted, scene and wardrobe changes would be difficult, and walking or dancing on the stage would be dangerous because of the cables strewn about.

Through advances in wireless microphone technology, as well as the availability of more affordable systems, stage productions now have freedom of movement both onstage and off. Audio professionals should look for bodypack transmitters that are easier to conceal and more comfortable for the talent.

The latest digital wireless systems enable the use of many wireless channels in congested RF environments. There are rules for using wireless, however, and one must follow them to ensure interference-free performance. Most of the rules pertain to frequency selection and antenna usage. Wireless microphones are available in a variety of frequency ranges. As available RF spectrum becomes less plentiful due to recent Federal Communications Commission (FCC) changes in the US, be sure to explore the different ranges available for wireless microphones, as well as the pros and cons of each.

Other Options

The previously discussed microphone techniques focused on the use of one lavalier microphone on each performer. Although that is the preferred method, it can be cost prohibitive in many smaller theaters, as well as in schools, community theaters and church pageants.

Boundary microphones (also known as pressure zone or PZM microphones) are an alternative to placing a mic on each individual performer. Boundary mics are designed to be laid flat on an acoustically reflective surface—in this case, the stage itself. The reflective surface becomes part of how the microphone picks up sound. When using boundary microphones on a stage, one must evaluate if they will pick up too much foot noise during the performance.

Another alternative microphone technique for theater is the use of overhead/hanging microphones, sometimes called choir microphones. These capture sound by hanging down from above the stage. Using overhead microphones to capture sound from above can provide decent sound reinforcement for a larger area, but, much as with boundary microphones, expectations should be kept realistic. Choir microphones are farther away from the sound source than even a microphone on a floor stand would be, and they will pick up more ambient sound than preferred.

That, in addition to the possibility of these mics actually being closer to loudspeakers than to the sound source, can increase the risk of feedback.

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