12--Microphone Techniques
P-Pops
Talking directly into a diaphragm of a microphone will cause a nasty side effect called "P-popping". P-popping is a horrible explosive bass "thump" you hear when a speaker uses certain letters (P's and B's) and speaks right into the mic. You cannot remove P-pops from the audio once its there.
When speaking into a microphone, you should talk "across" or just over the microphone rather than directly into the diaphragm. This will eliminate a good part of this problem. Another solution to P-popping is the use of a Pop Filter; these are large circles you place in front of the mic and are not visually acceptable in live situations. To help reduce (or in many cases eliminate) this low frequency distortion, simply roll off the low frequency response of the microphone in use. Keep in mind that the human voice has little (if any) energy under 120 Hz, so rolling off the equalization of that microphone will not loose any program response but certainly will eliminate the P-pops and handling noises. This is a trick used by the leading front of house mixing engineers.
Level
It is very important to keep a source at the same distance from the mic so the volume of the source does not change drastically over the PA or in the recording. It is critical in vocals to keep the lead singer "out front" and at a relatively constant level. If a singer moves his head around a lot in front of the mic, the level will go up and down, making the singer loud and then soft, understood and then not understood. So practice keeping your mouth at the same position relative to the mic as much as possible, except when you really belt it out and need to back it off a bit. One huge change in the level and pattern of the microphone will occur if you cup your hand around the ball or where you speak into. Hold the mic on it's handle, not the ball.Handling Noise
Nearly all microphones make noise when you rub your hand on them or tap them when they are amplified on PA. This rumble or handling noise is impossible to remove. Cardioid mics can be a problem especially in the low frequency area. Professional sound engineers solve this by reducing the low end response of the vocal mic at the mixer. Most handling noise is in the 30-80 Hz region and since the human voice has little content there, rolling off everything under 80 Hz reduces the handling noise.
Mic Placement
Mics sound different depending on how they are pointed at the source. Sources also have different response depending on whether you are directly in front of them or not. We spoke about "on and off axis" before, which refers to whether you are directly aimed at the center (on axis) or off center (off axis) of something. Pointing a mic directly (on axis) at something sounds very different than pointing it to the side of something (off axis). If a trumpet is pointed directly at the mic it sounds different than if it is pointed to the side of the mic. Same is true for acoustic guitars, pianos, singers, etc. Experiment!
Important Extras
Windscreens
Windscreens are necessary in some applications. Made of acoustically transparent foam that fits around the head or windscreen of a mic, they help to reduce the noise created when the wind "blows" on the mic element while in use. If you know you will be using
microphones in a windy location, make sure you prepare for this possibility.
Shock Mounts
Shock Mounts are very useful and necessary accessories that float the microphone in a neoprene rubber band "cage", thus mechanically isolating the sensitive microphone element from vibration or thumps transmitted through a mic stand or desk top. This is vital for studio and broadcast applications where people might be hitting the table with their hands, walking on a wooden floor, etc.
Mic Stands
Mic Stands are an often neglected issue. "We just need enough stands to hold all of our mics" is a phrase often heard. Many will grab some of the 50 year old stands and if it holds the microphone, excellent. There are a number of very clever and high tech mic stands and booms available today. Pay attention to some of these. They will make your job easier and position that microphone exactly where you need. The new Heil SB 2 is one of these tools. They are perfect for getting microphones into tight places around drum kits and guitar amplifiers.
Listen, Listen!
It is surprising how many folks work in sound but don't listen. When you set up a PA or recording system, budget the time to listen to each microphone univocally during set up to be sure it works correctly and sounds good. This is where you can spot a bad cable, connector or defective mic. Try different mics on different instruments and vocals. Each model has a unique tone and sound to it and "fits" with a particular source better than other mics. One singer may sound better with one mic than another. The sax may sound better with the mic that doesn't work so well on vocals. A good mixing engineer is an artist too and the microphones are the instruments---colors on the palette to build the sound he or she wants to achieve. Determine for yourself which sound is the best for your particular situation. Learn to classify the sounds and audible characteristics of each microphone you own and know where to put them before you get to the gig to get the most out of them.
Listening is a mental process. Hearing is a physical process.
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