5. Low Cut
This is a low-cut filter with a corner frequency of 75 Hz used to filter out rumble,
wind noise, breath thumps, stage noise and other low-frequency components
that rob power from the amplifiers and muddy the signal. The pre-EQ signals sent
to the AUX sends are picked up after this switch so that the monitors can also
benefit from this filter.
6. Hi EQ
Ashelving type of active tone control that varies the treble frequency levels
±15 dB at 12 kHz. It is designed to remove noise or to add brilliance to the signal,
depending on the quality of the source.
7. Hi/Mid EQ
Abandpass (peak/notch) type of active tone control that varies the upper mid-
range frequency levels ±15 dB at 3.1 kHz. This frequency is optimum for bringing
out the clarity of a vocal mic without adding harshness or grit, or can reduce high
frequency feedback.
8. Low/Mid EQ
Abandpass (peak/notch) type of active tone control that varies the lower mid-
range frequency levels ±15 dB at 250 Hz. Aslight cut in this frequency will usually
help a mic that has a proximity effect to become more intelligible in close talking
situations. It will also be useful to solve common feedback problems.
9. Low EQ
Ashelving type of active tone control that varies the bass frequency levels ±15 dB
at 70 Hz. It will add depth to thin signals or clean up muddy ones.
Channel Functions
1. Line Input
1/4" balanced (TRS) high-impedance input for high-level signals. The tip is the
positive input, which should also be used for unbalanced inputs. This input is
connected through a 10 dB pad to the Mic Input (#2). The two inputs cannot
be used simultaneously.
2. Mic Input
XLR balanced low-impedance channel input optimized for a microphone or other
low-level source. Pin 2 is the positive input. Because of the wide range of gain
adjustment, signal levels as high as +10 dBu (2.45 V RMS) can be accommodated.
This connector has 48V on pins 2 and 3 (pin 1 is the ground reference) when
the phantom power is enabled. (See note on #23.)
3. Insert
1/4" stereo (TRS) jack allows an external device to be inserted into the signal
path before the EQ. The tip has the send signal, the ring is the return input. A
switch in the jack normally connects the send to the return until a plug is inserted.
4. Gain
Varies the input gain to allow for a wide dynamic range. Proper adjustment of the
input gain will maximize the signal-to-noise ratio. It should be set by depressing
the PFL switch (#18) and adjusting for a 0 dB (+4 dBu) level at the L-R meters.
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