Specifications

110
Active Low-Cut Filters
LC 60 U (60 Hz), LC 120 U (120 Hz)
– active low-cut filters for phantom-powered micro-
phones, in particular CCM C
OMPACT CONDENSER
MICROPHONES and CMC microphones of the Colette
modular system
– for standard phantom power, 12 V or 48 V
These electronic filters can be inserted anywhere in the
microphone cable path. With a rolloff of 18 dB/octave,
the LC 60 U suppresses low-frequency acous tic inter-
ference (e.g. wind noise, or solid-borne infra sonic
noise such as handling noise during boom operation)
without detracting from the sound quality of voice
recordings. Under extreme conditions the LC 120 U
can be used, though it may have an audible effect on
the sound of a voice. Both filters can help prevent
overloading the input circuit to which a micro phone is
connected – a problem which occurs more often than
many people realize.
The specifications of the SCHOEPS microphones
(sensitivity, noise, source impedance) remain nearly
unchanged with the LC.
These low-cut filters are suitable not only for SCHOEPS
microphones but also for phantom-powered micro-
phones of other manufacturers, provided that they have
a current consumption of at least 2 mA. Other wise the
maximum sound pressure level would be reduced.
Please note:
The use of two LC in series is possible, particularly
with SCHOEPS microphones, but is not recommended.
The cutoff frequency would be raised, and the maxi-
mum output level with 12-Volt operation would be
lowered. In no case should three LC be cascaded,
especially if the microphones have less than 4 mA cur-
rent consumption.
Technical Specifications:
Filter: in-line low-cut, Butterworth, 18 dB/octave
Cut-off frequency (-3 dB): LC 60 U: 60 Hz, LC 120 U:
120 Hz
A maximum of two filters may be used in series,
which would then result in a 36 dB/octave slope.
Output impedance: 40 Ohms at 1 kHz with
SCHOEPS CCM compact microphones or CMC
microphones of the Colette modular system
Gain: 0 dB
Maximum output voltage: ca. 1 V when 4 mA cur-
rent is being drawn
Diameter: 20 mm
Length. 94 mm
Surface finish: nickel
Active Low-Pass Filter LP 40 U
– for adapting the signal from a pressure (omnidirec-
tional) microphone to fill in the bass region of direc-
tional microphones (especially with the OCT system)
– for phantom-powered microphones
The low-frequency response of any directional micro-
phone is inherently inferior to that of omnidirectional
(pressure) microphones. When using directional micro-
phones, one can extend the low-frequency response
by adding in signals from omnidirectional microphones
that have been low-pass filtered with a device such as
the LP 40.
The LP 40 filter is designed to extend the frequency
response of the SCHOEPS supercardioid (MK 41(V) or
CCM 41(V)) with the lowest possible ripple. This makes
it ideal for use with the OCT front surround system
(pg. 132); it can also be used to extend the response of
directional microphones with other patterns.
Electronic Accessories
COLETTE
modular
CCM
compact
COLETTE
modular
CCM
compact
LC 120 U