Peavey 600 - Page 3

facturer's mixers that only have switchabte fixed
attenuation of maybe 10 to 20 dB, where some¬
times 10 dB may not be enough and 20 dB may be
too much attenuation. The 600 Mixer's Input
attenuator Is continuously variable from 0 dB to
-40 dB.
The MONITOR SEND CONTROL (2) Is
the channel mixing element for determining the all-
Imporiaitt monitor mix, The signal for the moni¬
tor send is obtained right after the Input preamp
and before the channel EQ. This Is referred to as
a Monitor Pre-send Control, I.e., it is before orpre
to the channel equalization and slider level control.
This makes It independent of these controls, mean¬
ing that any changes made to the EQ or channel le¬
vel will not affect the monitor system. Having the
monitor send with the pre capability is absolutely
VITAL to avoid feedback of the monitor system
when EQ and normal Incremental output varia¬
tions are made in the channel fader during the
course of the performanpe.
EQUALIZATION - The equalization cir¬
cuitry of the 600 Mixer Is the latest active type,
utilizing negative feedback technology. We select¬
ed circuitry that produces a "'shelving" type of
action because the conventional type circuitry used
by some manufacturers tends to create erratic, or
sometimes harsh sounding results when in the near-
maximum boost positions. These two equaliza¬
tion controls will produce extremely smooth ac¬
tion as well as giving effective tone control. Ex¬
perience will show their utility in achieving pro¬
fessional channel equalization on the job.
U should be remembered that these active
equalization circuits are a form of "electronic
crossover" in which the equalization controls are
similar to level controls for their respective fre¬
quency bands.
Generally, it is poor operating practice to
use both equalizer controls In the deep cut
(counter-clockwise) positions since this results in
substantially lower gain from the channel. It
should be remembered that the balance of highs
and lows is a relative situation, and cutting over¬
all channel gain should properly be done by the
output slide attenuator or Input attenuator.
The LOW FREQUENCY EQUALIZER <4)
is capable of better than 15 dB boost or cut @100
Hz with a sloping characteristic exhibited up to the
crossover point, The shelving action of this control
has proven to yeild a much more satisfying and ef¬
fective equalization characteristic than some of the
"wide open" equalization circuits claiming 20- 25
dB boost and cut. The action of this equalization
control is conventional and should present no pro¬
blem in operation. Boost is obtained in the right-
hand (clockwise) position while cut is obtained in
the lefthand (counter-clockwise) position. The ver¬
tical (12 o'clock) position yields a flat (no boost or
cut) response and is the position from which all
tonal balancing should be started.
The HIGH FREQUENCY EQUALIZER (3)
is capable of 15 dB boost or cut @ 5 KHz with a
shelving characteristic sloping down to the cross¬
over point. The boost or ojt action of this control
is very similar to that of the low equalizer with the
exception of its high frequency effect. Boost is ob¬
tained to the right of center position while cut Is
obtained to the left of the center position, Flat
response Is obtained in the center (12 o'clock) po¬
sition.
Caution should be exercised in using ex¬
treme low-frequency boost to avoid emphasing
objectionable wind noises or rumble from the mi¬
crophone as well as any hum that might enter the
mixer from external sources. Excessive treble
boost should be avoided to keep residual noise
from the amplification circuitry to reasonable le¬
vel as well as to avoid a strident or screeching
tonality in the output program material.
In sound reinforcement, there is nothing
holy about an entirely flat equalization setting. If
it is necessary to use moderate amounts of equal-
Izatlof^, then you should be willing to do so, con¬
sidering that the "ideal" flat settings are almost
never used, even In the recording studio, and even
less often in most sound reinforcement applica¬
tions.
The EFFECTS SEND CONTROL (5) is the
channel level for determining the amount of signal
from each respective channel to be sent to the ef¬
fects output or to be mixed into the reverb sum¬
ming buss. The effects send circuit has been de¬
signed CO provide multiple functions which will be
explained further In the master control section.
The CHANNEL ATTENUATOR SLIDER
(6) is the output level control that determines the
mix into the main summing buss. Its calibration is
in decibels of attenuation and this is why the num¬
bering sequence goes from off (infinity *cc ),or
maximum attenuation to zero (0), or no attenua¬
tion. Remember that attenuation is the cutting or
reduction of the signal level i.e,, the more attenua¬
tion, the more you have cut down the signal level.
The output fader is calibrated in accordance with
standard practice for professional audio equip-
ment-
Proper setting of the Input attenuator (pad)
should produce adequate gain within the input pre¬
amp to allow slider settings approximately In the
center (approximately -40 to -20 dB). You should
remember that the input attenuator is a kind of
pre gairt control and its settings will most definite¬
ly influence the settings for the output slider with
any given ir>put signal. The input attenuator
should be adjusted for the maximum gain that will
allow distortion free performance, then the output
slider level should be adjusted for proper mix.
It is very poor operating practice to use the
input pads in the extreme cut portions and then
have to set the output sliders in their close to max¬
imum positions to obtain adequate channel output.
This type of operation results in less than optimum
signal-to-noise ratios as well as contributing to
headroom problems. As with any system, "com¬
mon sense" must be combined witfi operating