Crest Audio HPW owner manual Mono input, If the channel peak LED is

3mono input

HPWTM owner’s manual

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+48V - +48 volts DC is applied equally (through current-limiting resistors) to both pins 2 and 3 on the mic-input XLR connector. This feature is used with condenser micro- phones and active direct boxes that require an external DC voltage (phantom power)

in order to operate.

For dynamic or ribbon mics, phantom voltage is not required and should be switched OFF.

NOTE: Operating this switch (“ON” or “OFF”) causes large voltage swings to occur at the input of the mic preamp. Care should be taken to insure that the channel is muted, or the main faders are pulled down, to prevent a “pop” from reaching the audi- ence.

pad - When engaged, the input signal is attenuated by 25dB to prevent strong signals (from kick drums or lead vocals, for example) from overloading the preamp stage.The pad is used to bring a hot mic-input signal down to a controllable level, or when a line- level signal is present at the XLR input jack. This affects both the XLR and the 1/4” inputs.

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The 48V switch should not be engaged when using standard (dynamic) microphones or other sources that do not use phantom power.

If the channel peak LED is	+
illuminated, first try lowering
the input gain control.

Only when this method is unsuccessful should the pad switch be engaged.

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gain - The Input gain control range is closely related to the status of the PAD switch. In order to establish proper gain structure in the console, input gain settings must be set correctly, using the PFL switch and Solo system.The optimum gain setting will result in a 0dB level when checked using the PFL metering.

polarity (reverse) - This feature reverses the phase of the input signal and is used for correcting or minimizing polarity and phase related errors. For example, occasionally a bal- anced input connection is reverse-wired before it gets to the mixing console.This can hap- pen in microphones, or in snake line interfaces. By using the polarity button, this type of error can be corrected.

normal polarity (Pin 2 Hot) - switch “IN” position reverses polarity

lo-cut filter - This filter reduces or eliminates unwanted low frequencies without substantially affecting the program material. Quite often, such unwanted low frequen- cies are included with mic- or line-input signals. For example, stage rumble or wind can be picked up through vocal mics.The cut-off frequency of the filter is 70 Hz and the slope is -18dB per octave.This type of filter is also referred to as a Hi-pass filter (HPF). It allows the hi-frequencies to pass, but it stops the lo-frequencies.

lo cut switch

When this button is depressed, Lo-Cut filter is on.

When similar signals from	+
different channels are com-

bined, phase cancellations can occur.

Reversing the polarity of an input signal can often minimize such phasing errors.

When performing outdoors,	+
wind-induced, low-frequency

rumble can get into the input channels thru the microphones.

Engaging the Lo-Cut filter can eliminate these power-stealing low frequencies.

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