Crown CM-200A - Manual (Page 4)

How to reduce phase cancellations
between two mics
If two microphones pick up the same sound source at
different distances and their signals are fed to the
same channel, this might cause phase cancellations.
These are peaks and dips in the frequency response
caused by various frequencies combining out-of-
phase. The result is a colored, filtered tone quality.
To reduce phase cancellations between two micro-
phones:
• Mike close.
• Spread instruments farther apart.
• Follow the 3 to 1 rule: The distance between mics
should be at least three times the mic-to-sound
distance. For example, if two microphones are each 1
foot from their sound sources, the mics should be at
least 3 feet apart to prevent phase cancellations
(Figure 2).
How to reduce phase cancellations
from surface reflections
Sometimes you must place a microphone near a hard
reflective surface. Situations where this might occur
are recording drama, musicals, or opera with the
microphones near the stage floor, recording a piano
with the mic near the raised lid, or recording an
instrument surrounded by reflective baffles.
As described in the Crown Boundary Mic Application
Guide, these situations can cause phase cancellations
which give a strange tone quality. Solve the problem
by using Crown PZM or PCC microphones mounted
to the piano lid, wall, floor, or other large flat surface.
How to reduce handling and stand
noise
• Use an omnidirectional microphone such as a GLM-
100, CM-150, or any PZM.
• Use a directional microphone which is relatively
insensitive to handling noise, such as the CM-200A
or CM-700.
• Use a directional microphone with an internal shock
mount.
• Use a shock-mount stand adapter on a mic stand,
such as the CMSM.
• Place the mic stand on foam or sponges.
How to reduce proximity effect
Proximity effect is the bass boost you hear when you
mike close with a directional microphone. The closer
the mic is to the sound source, the more bass you hear.
To reduce proximity effect:
• Use an omnidirectional microphone.
• Turn down the excess bass with your mixer’s EQ.
How to achieve a natural
tone quality
• Use a microphone with a flat frequency response,
such as: CM-700, CM-150, GLM-100, or a PZM-
30D or PZM-6D set to “flat” response.
• Move the mic around until you find a spot where the
monitored sound is natural.
• Place the microphones as far from the sound source
as the source is big. For example, the sound board of
a guitar is about 18 inches long. Place the mic at least
18 inches away to pick up all the parts of the guitar
about equally.
• If you must mike close to reduce feedback or leakage,
use your mixer’s EQ to restore a natural tonal
balance.
How to achieve a bright tone
quality
A “bright” sound is crisp, clear, trebley, and articulate.
To achieve a bright sound, use a microphone with a
rising high-frequency response, such as a Crown
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