LA Audio MPX10 - Manual (Page 15)

Page 15
Fig 4.1.1 Input section rear panel showing the Line/DI switch
+ 4 8 V switch
Pressing this switch applies +48V to both pins 2 and 3 of the Microphone
input connector. This Phantom Power voltage is commonly used to power
capacitor microphones and DI (direct injection) boxes via the input signal
cable.
To prevent the chance of damage to any external pieces of equipment, do
not use the +48V power option with unbalanced input sources ie. those
where pins 1 and 3 are connected together.
To avoid loud and potentially damaging electrical noise always turn down
monitor speakers and connect your microphone before switching phantom
power on.
P H A S E switch
Reverses the phase of the input signal.
Mostly used for correcting out-of-phase connecting cables although there
are certain acoustic problems and specialised miking techniques which use
phase reversal.
F I L T E R switch
This switch inserts a 75Hz (-3dB frequency), 12dB/octave high pass filter
into the signal path after the input amplifier.
Useful for removing low frequency sounds such as rumble and stage noise.
Can also be used in conjunction with the EQ section to fatten bass sounds
without producing excessive low frequency energy.
4 . 2 N O I S E R E D U C T I O N & C O M P R E S S O R S E C T I O N
NR (Noise Reduction) on the MPX10 is provided by a downward expander
which operates exactly opposite to a compressor. Signals falling below the
set Threshold are progressively attenuated rather than abruptly switched
off as with a noise gate. Also with a gate if the signal is a constant level and
just below threshold the gate will stay closed (no signal passes). With the
Expander there will be an output but at a reduced level. The further the input