Behringer M IC 2200 - Manual (Page 16)

16
ULTRAGAIN PRO MIC2200
before the microphone preamp starts overloading. If distortion/overloading occurs at high volume levels, you
should reduce the gain with the MIC GAIN control.
5.1.3 PHASE REV. switch
The PHASE REV. switch reverses the audio signal’s phase by 180°. Usually, you won’t need this switch.
However, in some cases, it might be necessary to reverse the signal phase, for example, if a microphone cable
has been connected incorrectly (pins 2 and 3 interchanged), or if several microphones are used and specific
circumstances with regard to room acoustics are causing problems (e.g. frequency cancellations are usually
caused by phase problems). The phase reverse function will help you locate and eliminate any such problem.
5.1.4 LO CUT function
When you pick up acoustic signals with microphones, it is usually necessary to eliminate low-end signal
portions, such as rumble or pop noise, or other interference frequencies. Often, such frequencies have very
high amplitudes and do not only deteriorate the sound quality but can also damage the power amps or
speakers. Your ULTRAGAIN PRO features a tunable high-pass filter with a very high slope. Press the LO CUT
switch and adjust the FREQUENCY control, so that any disturbing frequencies are faded out as much as
possible, with the least damage done to the actual audio signals. Press/release the LO CUT switch several
times to make an A/B comparison.
5.1.5 Phantom power
Condenser microphones need a specific supply voltage polarizing the condenser diaphragm. This voltage can
be furnished from an internal battery, or an external power supply that is either connected directly to the
microphone or supplies the voltage through the microphone cable. In practice, this technique is usually referred
to as +48 V or phantom power supply, and uses the microphone cable to carry both the audio signal and the
supply voltage required for the microphone.
Please read this chapter thoroughly: phantom power can damage the microphone, if used improperly.
Fig. 5.1: Functional diagram of phantom power supply
We speak of phantom power when a microphone cable is used to carry several signals, with a DC voltage
“layered” on the actual audio signal. The typical phantom DC voltage is +48 V, which is applied both to the
positive (pin 2) and negative inputs (pin 3) of the XLR connector, using current-limiting resistors. As the
phantom voltage is split up in a balanced configuration among the signal leads, there is no need to apply it
directly to the microphone transducer or the microphone itself, where it could damage the transducer and/or
capsule. In an unbalanced configuration, DC voltage would be applied directly, which would inevitably lead to
disturbing noise or could even damage the electronics.
To eliminate this risk, the BEHRINGER ULTRAGAIN PRO automatically disables the unbalanced phone jack
in MIC mode. Microphones can thus only be connected to the XLR connector.
5. APPLICATIONS