Preattenuation Pad; Highpass Filter; Cleaning; Microphone Body - AKG C451 B Bedienungsanleitung

USE
To obtain maximum gain before feedback, place the main ("FOH")
speakers in front of the micro phones (along the front edge of the
stage).
If you use monitor speakers, be sure never to point any microphone
directly at the monitors, or at the FOH speakers.
Feedback may also be triggered by resonances depending on the
acoustics of the room or hall. With resonances at low frequencies,
proximity effect may cause feedback.
In this case, it is often enough to move away from the microphone
a little to stop the feedback.
5.4

Preattenuation Pad

Preattenuation
Pad
Figure 4: Preattenuation Pad
If you are miking up an extremely loud sound source or have
placed the microphone extremely close to an instrument, the
diaphragm may be exposed to extremely high sound pressure
levels. As a result, the electrical output signal of the transducer
may become high enough to overload the subsequent impedance
converter/preamplifier and introduce audible distortion.
To minimize the risk of getting audible distortion, use the preatte-
nuation switch on the microphone shaft to switch in 10 dB (1:3) or
20 dB (1:10) of preattenuation.
26 C451 B MANUAL
5.5

Highpass Filter

1
2
3
Figure 5: Highpass filter switch
Low-frequency rumble or wind noise such as air conditioning
rumble, traffic noise, structure-borne noise, etc. that usually pass
unnoticed may become a clearly audible nuisance on a recording.
To minimize low- frequency noise, you can switch in the highpass
filter.
Depending on the spectra of the wanted and unwanted signals, set
the highpass filter switch on the microphone shaft from flat (1) to a
corner frequency of 75 Hz (2) or 150 Hz (3). In either position, the
slope of the filter is 12 dB/octave (1:4) downward.
6

Cleaning

6.1

Microphone Body

Use a soft cloth moistened with water to clean the surface of the
microphone body.
6.2

Wind screen

Wash the foam wind screen in soap suds.
Do not use the wind screen before it has dried completely.
C451 B MANUAL
cLEANINg
Highpass Filter
Microphone
Body
Wind screen
27