Distance from microphone affects performance

Basic microphone technique
Most microphones exhibit what is known as the "proximity effect". The result of this effect is that sounds which are made very close to the microphone are picked up with a greater bass response than sounds which are made further away. This is most important for presenters and vocalists to understand, because the difference that a change in working distance makes to the sound of their voice can be quite dramatic. It is especially significant for deep-voiced vocalists (usually male), because a greater proportion of their voice is in the frequency range which is subject to the proximity effect. At a working distance of greater than about 4 to 6 inches (10 to 15 cm), the proximity effect can be ignored. As the distance decreases from this down to zero, the amount of bass emphasis increases. Good microphone technique will add to your effectiveness a performer. Keep the following points in mind when using a hand held microphone.

1. The distance from the performer or instrument to the microphone has a significant effect on the sound. For increased bass response, get close to the microphone (within 6 inches or less), the closer the microphone is to the sound source, the more the bass response will be increased.

2. Beneficial changes in the level and character of sound coming from the loudspeakers can be achieved by changing your distance from the microphone. For instance, working up close can provide maximum bass enhancement without feedback. Practice and experience will develop your skill in varying your distance to achieve the desired effects.

3. For maximum isolation from other sound sources and background noise, position the microphone as close to the source as practical and aimed at the sound source.

Feedback and directional microphones
A performer's worst enemy in using a microphone is feedback. These is a harsh howl or squeal that occurs when the microphone picks up sound from the loudspeakers, re-amplifies and reproduces it over and over again (see Figure 2). This vicious circle results in feedback.

Microphone with cardioid polar-pattern (shaded)
Microphone oriented toward loudspeaker result in feedback	Microphone oriented away from loudspeaker reduces feedback
Feedback loop figure 2	Feedback loop figure 3

A directional microphone with a cardioid pickup pattern aids in preventing feedback because it rejects sound that originates from the sides and rear (see Figure 3). Sound pickup from the sides is reduced by about one half, and pickup from the rear is reduced by about nine tenths. You can hear this reduction in pickup by speaking into the microphone as you rotate it from front to back.

If you use your directional microphone close to the performer or instrument, you will ensure that the direct sound will be much louder than the feedback-producing amplified sound. Because less amplifier gain is required to achieve the desired overall loudness, the amplified sound will likely remain below the volume that triggers feedback.

Other hints on preventing feedback:
Keep the loudspeakers as far to the sides as possible.
Be sure that the microphone point toward the performers and away from the loudspeakers.
Make certain that any stage monitor speakers are positioned in front of the performers and face the insensitive rear of the microphone.

The cardioids directional characteristics of your microphone are provided by means of rear sound entry. These are ports that cancel sounds originating from the sides and back of the microphone. It is therefore important that these ports not be covered at any time. When holding the microphone, do not allow your hand to partially cover the grille (see Figure 4).

DO NOT COVER THE GRILLE WITH YOUR HAND
FIGURE 4

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