later stage would not solve the problem.
A condenser microphone represents two cir-
cuit stages: the capsule and the amplifier. In
practice, capsules are rarely overloaded except
by explosions or very strong wind; the only
sound pressure levels that could overload a
SCHOEPS
capsule are so extreme – ca. 150 dB
SPL – that they would quickly damage human
hearing. A properly powered
SCHOEPS
MSTC
64 can normally handle 130+ dB sound pres-
sure levels, depending on the capsule type.
Such levels rarely occur in unamplified sound,
though their equivalents can be caused by wind
when directional capsules are used, just as with
the MSTC 64. In addition, proper powering
should not be taken for granted; insufficient
or incorrect microphone powering has proved
to be the cause of many otherwise mysterious
“overload” problems.
If wind and powering can be excluded as
possible issues, however, overload is far more
likely to occur in the input circuitry of mixers,
preamps or recorders than in the microphone.
This is true particularly with consumer audio
equipment, though even today some profes-
sional equipment is still designed primarily for
use with dynamic micro phones or with earlier,
less sensitive condenser microphones. If an
input sensitivity control is available, it should
be set low enough to avoid input overload,
but not so low as to cause excess noise –
though a few dB of extra hiss is preferable to
the risk of hard clipping. Level meters and
overload indicators don’t generally detect
input overload even in fully professional
equipment; they operate only at later stages
of the circuitry.
If overload occurs where powering, high
sound pressure levels and wind are not the
problem and an input sensitivity control can-
not be turned down, the next logical step is
to plug in a balanced resistive ”pad” (attenu-
ator) such as the
SCHOEPS
MDZ 10 or MDZ 20
at the preamp input. If the sound quality
improves, leave the pad in place; as long as a
microphone isn’t being overloaded, it is always
better to pad the preamp input than the micro-
phone.
Low-frequency disturbances such as wind
and solid-borne vibration may not be directly
audible as such, but infrasonic noise can still
cause overload in some stage of the signal
chain. A windscreen then becomes the first
line of defense. But low-frequency noise can
also be effectively suppressed the active low-
cut filters LC 60 or LC 120 which can be
placed at the input of a phantom-powered
preamp.
Overload which does not otherwise seem
to make sense may actually be a symptom of
incorrect or inadequate microphone powering.
Powering systems and their requirements are
discussed near the beginning of this manual
on page 5.
The least expensive, most helpful trouble -
shooting tools are:
– a known good microphone cable
– a simple pop screen such as the
SCHOEPS
B 5 (or for outdoor recording, a wind
screen such as the
SCHOEPS
W 5)
– a balanced, in-line resistive attenuator (”pad”)
such as the
SCHOEPS
MDZ 10 or MDZ 20
– an ordinary multimeter or the
SCHOEPS
PHS 48 phantom power tester
Care and Maintenance
Please take care to avoid placing the micro-
phone in a dusty environment. Keep it in its
case (e.g. the wood carrying case it comes
with) when not in use, since any dust that
gets inside the capsules can adversely affect
their functioning. Dust can affect the micro-
phone in the following way: In combination
with humid ity it can lead to condensation and
thus popping and crackling noises (often
described as ”frying sounds”).
What to do if …
the microphone is noisy (clicks and pops) in high
humidity?
– If the microphone is brought from the cold
outdoors into a warm environment, snap-
ping or clicking noises can result from the
condensation of moisture. In such a case the
SCHOEPS
GmbH · Spitalstr. 20 · D-76227 Karlsruhe (Durlach) · Tel: +49 721 943 20-0 · Fax: +49 721 943 2050
www.schoeps.de · [email protected]
Care and Maintenance
16
English
