Equalizer Functions; Using An Equalizer/Feedback Controller With An Automatic Mixer; Basic Mixer Operation - Shure SCM810 User Manual

EQUALIZER FUNCTIONS

Low Cut Filter (High-Pass)
The low-cut (or high-pass) filter allows all frequencies above its
cutoff point to pass from filter input to filter output without attenua-
tion, while frequencies below the cutoff are attenuated (see Figure
7). The cutoff point is defined as the frequency where the signal
has dropped 3 dB relative to the flat, or bandpass, region. Below
the cutoff point, the filter exhibits increasingly more attenuation as
the frequency diminishes. The rate at which this attenuation oc-
curs is defined in decibels per octave (dB/oct). The SCM810 has a
one-pole, low-cut (high-pass) filter of 6 dB per octave.
Low-cut filters are ideally used for attenuating, or rolling off, the
audio signal where extraneous noise, excessive proximity effect,
or other unwanted material is present. For example, the low-fre-
quency vibration cause by footsteps and vehicle traffic can be
transmitted through microphone stands to the microphone, and
then into the sound system. These frequencies, typically ranging
from 5 to 80 Hz, are generally not desirable.
High-Frequency Shelving
The fixed-frequency equalizer produces a 6 dB boost or cut at 5
kHz and above (see Figure 8). High-frequency shelving is ex-
tremely useful for boosting flat frequency response, tempering
very sibilant vocal microphones, or enhancing the sound of off-
axis lavalier microphones.

USING AN EQUALIZER/FEEDBACK CONTROLLER WITH AN AUTOMATIC MIXER

When setting up a sound system which has an outboard equaliz-
er or feedback controller in the signal chain, set the SCM810 to
MANUAL. This activates all microphone inputs, so every pos-
sible feedback path is open. With the SCM810 in MANUAL
mode, equalize the sound system and/or "Ring Out" the room to
set the feedback controller.
1. Turn on the Power switch.
2. Adjust each channel level so that its Overload LED flickers
only during very loud speech or noise.
3. Turn unused channel controls full counterclockwise.
4. Adjust the SCM810 Master level control for the required out-
put level, as indicated by the output peak meter.
NOTE: The extreme sensitivity of the IntelliMix circuitry may allow some channel gating due to static discharge or electrical dis-
turbance to the power or signal lines. The unit will not be damaged: normal operation will resume after the disturbance ceases.
+10
+8
+6
+4
+2
0
-2
-4
-6
-8
-10
After equalizing the sound system, set the SCM810 to AUTO-
MATIC mode. Remember that the input of an automatic mixer
drops by 3 dB every time the number activated inputs doubles.
When using an SCM810 in MANUAL mode, the master output
drops by 9 dB when all 8 inputs are activated. Conversely, it will
rise by 9 dB when switched back to AUTOMATIC mode.

BASIC MIXER OPERATION

5. If a headphone monitor is to be used, adjust the PHONES
NOTE: The SCM810/E mixer is fully automatic. For most ap-
plications, no additional adjustments are required.
7
+2
FULL CW
0
-2
-4
-6
-8
50%
ROTATION
-10
20 100
FREQUENCY (Hz)
LOW-CUT FILTER EFFECTS
FIGURE 7
200 1,000
FREQUENCY (Hz)
HIGH-FREQUENCY SHELVING EFFECTS
FIGURE 8
control knob until the desired volume level is reached.The
SCM810/E is now ready to use.
FULL CCW
1,000 5,000
FULL
CW
50%
ROTATE
FULL
CCW
10,000 20,000