The live sound world goes well beyond the concert realm into areas such as the performing arts, including theatrical plays, musicals, and opera. It also can extend to things like magic shows, dance troupes, puppet shows, jugglers, and even ventriloquists.
Each act presents special microphone requirements, which we’ll explore here. Performing arts applications usually involve at least one of four types: floor mics, hanging mics, wireless lavalier mics, and wireless headworn mics.
On The Floor
Stage floor microphones, also known as boundary mics and commonly seen on boardroom tables as well, are quite effective for area pickup of stage productions, particularly if you’re on a tight budget. These mics offer a half-supercardioid or half-cardioid polar pattern, which rejects sound from the rear such as a pit orchestra.
They should be placed on the stage floor near the footlights. They’re nearly invisible so they don’t detract from the set. Some models are rugged enough to withstand kicks by dancers and can even be stepped on without damage.
Why not use a conventional mic on a desk stand? Sound reflections from the stage floor can color the tone quality and give a hollow sound. That’s due to phase interference between the direct sound from the actors, and delayed reflected sound off the stage floor. Boundary (floor) mics capture the direct and reflected sounds in phase, preventing the hollow, comb-filter effect.
With the proper loudspeaker placement, floor mics can sound clear and natural, and can be turned up loud enough for everyone to hear the performance and understand the words. One centrally located floor mic might work effectively with a 20-foot-wide stage, but typically, the best results are attained with mics spaced 12 to 15 feet apart.
They’re designed to not be sensitive to floor vibrations, but they do “hear” footsteps acoustically, as our ears do. Normally this isn’t a problem because the audience sees and hears the actors walking across the stage.
Many auditoriums are designed with loudspeakers over or near the stage, which can cause feedback with floor mics (and hanging mics). If you’re able to move the loudspeakers, great, but if not, sometimes the only solution is to go with a closer miking solution such as lavalier or headworn.
Suggested loudspeaker placement, if possible.
Here are some tips to enhance gain-before-feedback with stage floor mics:
1. Place/move loudspeakers close to the audience and as far from the mics as possible. Ideally, if you’re working with a portable PA, place the loudspeakers near the side walls, even with the third row from the front. If coverage isn’t reaching far enough, add two more loudspeakers, left and right, further into the audience area.
2. Ride the mic faders on the mixer up and down, following the action on stage. Ideally only one mic is on at a time. The more open mics, the more feedback.
3. Place the mics as close to the actors as possible (without getting in their way).
4. Train the actors to project their voices loudly toward the audience.
5. Don’t cover the mic grille holes with tape. It can cause feedback and change the sound of the mic.
6. If you can’t hear sibilance (“s” sounds) clearly, gently boost high-frequency EQ (just a little) at 10 kHz, but watch out for feedback.