AKG C 542 BL Mode D'emploi page 11

sponse and the more extended the microphone's bass
response.
The C 542 BL is an omnidirectional microphone that
will pick up sounds originating in front of the boundary
only. This has been described in many papers and arti-
cles about boundary microphones published over the
years.
When you place the microphone on a large acousti-
cally reflective surface (boundary), its sensitivity will be
about 6 dB higher than that of conventional omnidi-
rectional microphones. Such boundaries include wood
or stone floors, walls of similar materials, ceilings, or
large flat surfaces of certain instruments, e.g., piano
lids. This 6-dB increase in sensitivity also improves the
signal/noise ratio by the same amount. In addition, the
omnidirectional transducer (pressure microphone)
used in the C 542 BL is much less sensitive to footfall
and wind noise than unidirectional microphones are.
The rubber feet and supplied adhesive compound that
you may use to mount the microphone minimize resid-
ual noise from vibrating floors or walls.
The switchable bass cut filter in the phantom power
adapter further reduces low-end distortion caused by
footfall or wind noise, etc. The filter slope is approx.
12 dB/octave and its corner frequency (3-dB down
point) 150 Hz.
The microphone provides a low-impedance, electron-
ically balanced output. You can connect the micro-
phone both to balanced inputs with or without phan-
tom power and to unbalanced inputs. To use the
microphone with a balanced input with no phantom
power or an unbalanced input you will need an AKG
phantom power supply, e.g., the B 18.
2 Interfacing
2.1 General
The C 542 BL is a condenser microphone and there-
fore needs a power supply.
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