Managing sound for music is very different from managing sound for speech. Music is about fidelity; speech is about intelligibility. Anything that interferes with the ability to clearly hear words needs to be minimized or eliminated. While every space and situation is different, here are five general tips for better quality spoken audio:
1. More Microphones, More Problems
Every live/open microphone is another path for potential feedback and unwanted noise. When setting up your audio system, use the fewest number of mics possible and mute any that aren’t actively being used. This could be as simple as asking videconferencing participants to mute their laptop mic when they aren’t speaking, to a technician controlling multiple mics with a soundboard.
2. Watch your Spacing
Having two open microphones at different distances from the same sound is problematic. Avoid this by muting unneeded mics, moving them further away, or using directional microphones. If a presenter is wearing a lavalier mic and then steps up to the podium or picks up a handheld, make sure only one of the mics is active.
3. Know Your Mics
Polar patterns are ways of describing the sensitivity of a microphone in a given direction. Omni-mics capture sound uniformly from all directions and are more forgiving, while cardioid microphones have a more directional or “heart-shaped” pattern. Although cardioid microphones can be used to remove unwanted background sounds, you’ll need to encourage users to talk directly into them.
4. Beat Feedback
People often blame the microphone, but ‘feedback’ is caused by a combination of several things – acoustics, amplification levels, microphone directionality, or loudspeaker location. In a room with loudspeakers, avoid omni-mics because they cannot be adequately aimed. Be mindful of your mic positioning and if a speaker tends to roam, caution him not to walk in front of the loudspeaker with a live mic.
5. Soften the Room
Reflective (hard) surfaces can cause intelligibility because the sound bounces around the room and arrives at the microphone at slightly different times. Sound-absorbing wall and window treatments can significantly reduce room reverberation. If sound-treatment isn’t possible, try moving the microphone further away from the offensive surface.