SPL TwinTube, Руководство пользователя

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Analog Elemental Series
Preference Mic Pre | Control Elements
Pad
The Pad function allows you to attenuate the input signal by 20 dB so that you can process
even very high levels, i.e. from drums or brass instruments.
If the VU meter shows levels above +3 dB even while Mic Gain is set very low (and the -10 dB
button deactivated), the time has come to press the Pad button. It illuminates when it is acti-
vated.
Phase Reverse
With the phase reverse button you invert the polarity of the microphone signal. When not
pressed (button is not illuminated) the polarity is in phase. After pushing the button (button
is illuminated) the polarity is inverted.
The phase reverse feature comes in very handy if you have to switch the polarity of the XLR
input according to the polarity of the microphone or the microphone cable. The pin wiring of
the XLR sockets are as follows: Pin 1 = ground, Pin 2 = hot (+), Pin 3 = cold (-).
Sometimes it is useful to switch the polarity of a microphone, for example in the case of M/S
miking. A second classic application is the miking of a snare drum with two microphones that
are placed above and below the snare: Since both drum heads move in the same direction
when the drum is played, the microphones are out of phase. Switch the polarity of the bottom
mic and you avoid any cancellations when you join both signals in the mix.
High-Pass Filter
The high-pass filter, also known as rumble filter, helps to eliminate any interferences
within the lowest frequencies. The first order filter operates smoothly with 6 dB per
octave, starting from 75 Hz with -3 dB. This characteristic usually helps in most cases
and has the least sonic disadvantages. If you need to filter on a more extreme scale, even
second order filters (12 dB/octave) are overstrained frequently and sonic disadvantages
become more and more apparent. In those cases a variable filter is the means of choice.