Samson S83 Stereo Amplifier User Manual


 
23
Using Equalization
One of the most exciting aspects to using a mixer such as the S83 or S63 is hav-
ing the ability to shape a sound, using a process called equalization. But there
are few areas of sound engineering more misunderstood than equalization, and,
just as good EQ can really help a sound, bad EQ can really hurt it, so read on...
Every naturally occurring sound consists of a broad range of pitches, or frequen-
cies, combined together in a unique way. This blend is what gives every sound
its distinctive tonal color. The EQ section in a mixer allows you to alter a sound
by boosting or attenuating specific frequency areas. Both the S83 and S63 pro-
vide a ten-band graphic master equalizer (more about this shortly) as well as
independent equalization for each channel. The S83 offers four-band equaliza-
tion controls for each of the eight input channels. The center frequency areas
are, from high to low: 10 kHz, 2.5 kHz, 500 Hz, and 80 Hz. Each EQ knob is
labeled with the maximum amount of cut or boost provided (± 15 db in the case
of the highest and lowest frequencies and ± 12 db in the case of the two mid
frequencies). The S63 provides three-band equalization controls for each of the
six input channels. The center frequency areas are, from high to low: 10 kHz,
1 kHz, and 80 Hz. Again, each EQ knob is labeled with the maximum amount of
cut or boost provided (± 15 db in the case of the highest and lowest
frequencies and ± 12 db in the case of the middle frequency).
We provided these particular frequency areas because they have maximum
impact on musical signalsthats why they are sometimes known as sweet
spots. When an EQ knob is in its center detented position (0), it is having no
effect. When it is moved right of center, the particular frequency area is being
boosted; when it is moved left of center, the frequency area is being attenuated.
In both the S83 and S63, the high and low EQ controls employ what is known as
a shelving curve (where frequencies either above or below the specified area are
affected) while the mid frequency controls employ what is known as a bell curve
(where frequencies both above and below the specified area are affected).
The ten-band graphic master equalizer affects the overall output signal of the
S83/S63. Its main function is to allow you to tune the device to the particular
room environment you are in. Perhaps its most important job is to enable you to
eliminate ringing or feedback problems caused when a microphone is too close
to a loudspeaker. To accomplish this, start with all ten bands flat (that is, all ten
sliders at their detented 0 center position). Then, one by one, raise each slider
until you hear the feedback or ringing markedly increase. This allows you to
identify the problematic frequency area (it will most commonly be one or more of
the high mid-range or high frequency areas). When youve located the problem
area(s), its simply a matter of lowering that slider or sliders below the 0 point
-12
+12
2.5K
0
-15
+15
HIGH
0
-12
+12
500Hz
0
-15
+15
LOW
0
-12
+12
1 kHz
0
-15
+15
HIGH
0
-15
+15
LOW
0
30Hz 64Hz
125Hz 250Hz 500Hz 1K
2K
3K 5K 10K
+15dB
0dB
-15dB
30Hz 64Hz
125Hz 250Hz 500Hz 1K
2K
3K 5K
10K
S83 EQ section
S63 EQ section
Ten-band graphic master equalizer