User's Manual

8
BASIC MIXER OPERATION
1. Adjust each channel level so that its Overload LED flickers only
during very loud speech or noise.
2. Adjust the Low-Cut and High-Frequency controls adjacent to each
Input Gain control so that the microphones sound similar.
3. Adjust the Master level control for the required output level, as
indicated by the output peak meter. The SCM410 is now ready for
use.
LIMITER
Output limiters prevent distortion during loud program peaks without
affecting normal program levels. This keeps the devices connected to
the SCM410 output from becoming overloaded. Increasing individual
or Master controls on the SCM410 increases average output and, in
turn, the amount of limiting.
The limiter may be turned on via the rear panel DIP switch. The default
limiter threshold is +16 dBu. As supplied, the limiter is defeated.
NOTE: Limiter thresholds can be changed from their factory
settings. Refer to the INTERNAL MODIFICATIONS section.
EQUALIZER FUNCTIONS
Low Cut Filter (High-Pass)
Low-cut filters are used to reduce unwanted low frequency sounds
such as footsteps, motorized traffic, and to control proximity effect. The
SCM410 has a one-pole, low-cut (high-pass) filter of 6 dB per octave.
The low-cut filter allows all frequencies above its cutoff point to pass
through unchanged. Frequencies below the cutoff are attenuated (see
Figure 3). 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 fre-
quency diminishes.
LOW-CUT FILTER EFFECTS
FIGURE 3
High-Frequency Shelving
The fixed-frequency equalizer produces a 6 dB boost or cut at 5 kHz
and above (see Figure 4). High-frequency shelving is extremely useful
for boosting flat frequency response and tempering sibilant vocal mi-
crophones or enhancing the sound of off-axis lavalier microphones.
HIGH-FREQUENCY SHELVING EFFECTS
FIGURE 4
-10
-8
-6
-4
-2
0
+2
20 100 1,000
5,000
FULL CW
50%
ROTATION
FULL CCW
FREQUENCY
AMPLITUDE
200
-10
-8
-6
-4
-2
0
+2
+4
+6
+8
+10
1,000 10,000
20,000
FULL
CW
50%
ROTATE
FULL
CCW
FREQUENCY
AMPLITUDE