SCHOEPS SuperCMIT 2 U - Handbuch (Seite 14)

Important notes
Latency
Because of the >2 ms latency, it is not advis-
able for most people to monitor the output of
the SuperCMIT through headphones while
speaking into the microphone. The two output
channels of the microphone (SuperCMIT and
CMIT) have differing latency times (see specifi-
cations on page 17), and their signals should
not be mixed together.
Sound openings
In the area around the second, rear-facing
transducer there are eight sound openings for
the sake of acoustic transparency. Please be
careful not to block these openings, e.g. with
a stand adapter or other mounting device.
The size of these openings also makes it
important to keep their gauze covering from
being pressed inward.
Notes on EMC
(Electromagnetic Compatibility)
The SuperCMIT is insensitive to magnetic,
electrical and electromagnetic fields. But no
microphone can ever be fully immune to all
interference. The following rules can help to
prevent possible interference:
– Avoid placing the microphone or its cable
close to sources of interference such as
video monitors, digital equipment (comput-
ers), transmitters (cellular phones or PDAs),
high-voltage lines, high-power AC
adapters, lighting dimmers, etc.
– Use high-quality 110
Ω AES3 cable that is
no longer than necessary.
– Do not run microphone cables parallel to
AC power cables. If it is necessary for them
to cross, they should do so at right angles.
– The cable shield at the input of the receiv-
ing device should connect to the housing
of that device along the shortest possible
path, using DC coupling if possible, or at
least capacitive coupling.
SCHOEPS GmbH · Spitalstr. 20 · D-76227 Karlsruhe (Durlach) · Tel: +49 721 943 20-0 · Fax: +49 721 943 2050
www.schoeps.de · [email protected]
Important notes / EMC / Care
14
English
Gain / Limiter
Beginning with firmware version 1.33, digital
amplification of 30 dB can be activated in the
SuperCMIT by pressing each of the three push-
buttons twice each in turn. The order of the
buttons is unimportant (i.e. 332211 works as
well as 112233), but the two clicks of each
button must be a moment apart so that they
are distinct. The gain boost can be canceled by
repeating the button presses; also, if powering
is removed from the microphone, the amplifier
gain will reset to normal (0 dB).
A/D converters can convey the full dynamic
range of a microphone, which in principle
would make it unnecessary to “set levels” for
a digital microphone recording. But there still
are reasons for setting levels nonetheless. For
example, if a digital microphone is connected
to a portable recorder and the sound levels are
very low, the recorder's headphone amplifier
might be unable to produce enough volume
to allow monitoring the signals. Digital amplifi-
cation at the input to the recorder could solve
this problem, but if that is unavailable, then
the levels can be raised within the micro-
phone.
It can also be useful to raise levels before
feeding a digital signal to a D/A converter, to
help overcome the self-noise of the converter.
Digital amplification, unlike analog amplification,
need not affect signal-to-noise ratio. Of course,
the upward limit of the dynamic range is reduced
by the same amount as the gain that is applied.
Raising the gain of the SuperCMIT by 30 dB
would also lower its maximum SPL to 95 dB.
Thus, beginning with firmware version 2.0,
if the 30 dB additional gain is switched on,
digital limiters are also engaged to avoid over-
load on sound pressure levels of up to 125 dB.
These limiters, which are separate for the two
channels, have a fixed threshold of -3 dB,
ensuring that overload will not occur even on
brief peaks. These limiters do not increase the
latency of the signal processing in the micro-
phone.