C451 B MANUAL
C451 B MANUAL
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USE
USE
5
Use
5.1
Introduction
The rod-shaped body, accurate response, and many matching
accessories from AKG make it easy to use the microphone to pick
up a wide range of different instruments.
Read the hints below to get the best possible results.
5.2
Proximity Effect
Owing to their acoustic principle, unidirectional microphones
exhibit what is called "proximity effect".
This means that the lowfrequency content of a sound signal will be
progressively boosted as you move the microphone closer to the
sound source. Proximity effect begins to become audible at a wor-
king distance of about 2 feet (60 cm). Depending on the nature of
the sound source, proximity effect may be desirable or a nuisance.
Place the microphone closer to the sound source to accentuate, or
further away to reduce proximity effect.
Introduction
Proximity
Effect
5.3
Feedback in Live Sound Situations
Figure 3: Microphone placement for maximum gain before feedback
Feedback results from part of the sound projected by a speaker
being picked up by a microphone, fed to the amplifier, and projec
-
ted again by the speaker.
Above a specific volume or “system gain” setting called the
feedback threshold, the signal starts being regenerated indefinitely,
making the sound system howl and the sound engineer desperately
dive for the master fader to reduce the volume and stop the
howling.
To increase usable gain before feedback, the microphone has a
cardioid polar pattern. This means that the microphone is most
sensitive to sounds arriving from in front of it (from the sound sour-
ce) while picking up much less of sounds arriving from the sides or
rear (from monitor speakers for instance).
Feedback