Microphones: School Plays & Musical Performances

One important point should be made before we proceed. Successful results of proper microphone techniques are largely dependent on the quality of the loudspeaker system and the room acoustics. In fact, a poor speaker system will often prohibit the use of many of the techniques discussed in this article. Also, if an improperly designed speaker system is used in an auditorium with poor room acoustics, intelligibility will suffer. For our purposes, we will assume we are working in a room with reasonable acoustics and the main speaker system has been properly designed for theater reinforcement.

The primary goal of sound reinforcement for theatrical productions is to provide natural reinforcement of the human voice and at times blend those human voices with each other and balance them with other sources of sound such as instrumental accompaniment and sound effects. The theatrical environment also requires freedom of movement and minimal visual distraction. Three basic types of microphones are useful in an environment with the requirements and restrictions that we have mentioned: area microphones, wireless lapel microphones and handheld solo microphones (also usually wireless).

The most useful type of microphone for stage productions is the area microphone. Boundary microphones are the best choice for area microphones. Boundary microphones are usually flat, low-profile designs often incorporating a hard, flat plate surface as a base. Several manufacturers produce boundary microphones in both unidirectional (favoring one direction) and omnidirectional types. Only unidirectional boundary microphones should be considered for purposes of theatrical sound reinforcement. Unidirectional models will help increase the amount of amplification before the onset of feedback. Also, unidirectional boundary microphones are less sensitive to audience noise and can also help isolate voices from the orchestra or instrumental accompaniment. Models currently available include the Crown PCC-160, the Shure SM91 and the Audio Technica AT871. Although other manufacturers may have similar products available, these are the most commonly used boundary microphones.

Depending on the width of the stage, two to four boundary microphones can be placed across the front of the stage (see figures 1-3). The best method for determining how many to use for a particular production is as follows:

1. Start with one boundary microphone centered at the front of the stage. If any dialogue is lost at extreme stage left and right, then add an additional microphone.
2. Adjust the two mics so that they split the stage in thirds.
3. Increase the distance between the mics until extreme stage left and right are adequately reinforced.
4. Now check to see if dialogue from front center stage is noticeably lower in level compared to dialogue from someone centered in front of one of the two mics (make certain that both mics are on). If the center stage is weak in level, then add a third mic.
5. The third microphone should be placed at front center stage. The other two outside mics should be moved away from the center microphone until you start to notice a weak spot in dialogue reinforcement when someone is standing directly between the center mic and either outside mic.
6. Unless your stage is very wide, three mics should be sufficient. If you do feel the need for a fourth mic, use the same guidelines described above for determining the distance between microphones.

Place them as close to the front lip of the stage as possible. Determine which half of the microphone is least sensitive to sound. We'll refer to this as the back of the microphone. Make certain that the back of the mics are pointed toward any nearby sound sources that you do not want reinforced such as audience noise or excess sound from the orchestra. Avoid pointing the front of any two boundary mics toward each other. This will minimize the interaction of the two mics (see figure 4).

Now that you have determined the quantity and location of the front stage area mics, check to see how far upstage (toward the front lip of the stage) you can move before the dialogue starts to fade. If the blocking requires any areas upstage beyond which the front area mics "cover", additional area microphones will be needed. This will create a problem. Area microphones should not be located on the floor in any heavy traffic patterns during the production. Most importantly, any area mic that is inadvertently stepped on or bumped will make an annoying, distracting sound. Also, even though these area mics are designed to be rugged, the mic cable or connection can often be snapped off or bent . . . not good. There are creative solutions, however. Do not limit the use of area mics to the floor. Area mics can be mounted almost anywhere, including props or any overhead proscenium. Keep in mind that the larger, the flatter and the harder (more reflective) the surface that the area mic is fastened to the better the response of the area mic will be. Both the area mic and its cable can be mounted with gaffer tape (NOT DUCT TAPE) but be careful not to cover the microphone grill screen. If the area microphone is attached to a prop that is moved, connect it to a wireless transmitter. Now there is no cable to trip over or run over!

Area microphones can also solve unique production problems. For example, let's say that during one musical number the strength of the vocal ensemble is less than adequate because several of your stronger singers do not have sufficient time for an additional costume change. Simply locate an area mic backstage for those singers that should be heard but not seen. Now bring up the level on that area mic until the "backstage singers" are well blended with the rest of the group but not too prominent.

As with any sound system, the gain or volume of microphones which are not in use should be turned down. This method of operation will give you more volume on the active microphones before feedback occurs. If you need all the gain you can get (which is usually the case), the sound person will need to be constantly riding the volume controls by adjusting up the active microphones and turning down the unused ones.

We will discuss wireless mics in a future article. For now, we hope this information will provide better direction toward improving the quality of your theatrical reinforcement needs.

by Travis Ludwig © 1996 Internet Sound Institute (www.soundinstitute.com). This article is for personal use only. Any commercial reproduction is not permitted without permission. To obtain permission, contact ISI at hopi@soundinstitute.com

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