Owner's Manual

INTERFACE AND OPERATION
In general, the EQ2015 & EQ2030 graphic equalizers can be inserted into the audio
signal path at any convenient point where there is a nominal “line level” signal. About
the only signals with which it would not be appropriate to use the EQ2015 & EQ2030
would be very low level signals (i.e. microphone lines before the mic preamp) or
very high level signals (i.e. loudspeaker lines). The EQ2015 & EQ2030 will provide
excellent results when used with signals and input/output impedances normally found
in recording studios, sound reinforcement systems, or home Hi-Fi. Further details
on installation and operation are provided below for various applications. Please
refer to the section that most closely matches your application.
RECORDING STUDIO APPLICATIONS
The EQ2015 & EQ2030 have a variety of applications in the recording studio.
However, the primary application will likely be to precisely correct frequency response
errors in the control room monitoring system. In order to create a well balanced
product, it is essential that a professional recording studio utilize an audio mon-
itoring system that is a “neutral” or “colorless” as possible. The EQ2015 & EQ2030
were specifically designed for the task of removing color, or “neutralizing” audio
monitoring systems. An appropriate point at which to insert the EQ2015 & EQ2030
in the listening chain is between the mixer’s control room outputs and the inputs
of the stereo power amps. Input and output connections to the EQ2015 & EQ2030
can be made by way of either the balanced XLR connectors or the balanced/unbal-
anced 1/4” phone jacks.
If the EQ2015 or the EQ2030 is to be used for a variety of recording applications
rather than as a dedicated monitor equalizer, then the best place to interface it is the
central patch bay. By making the EQ’s inputs and outputs available at the patch bay,
the EQ can be patched into input or output channels of the mixer as desired. In
addition to the infinite variety of audio frequency response contours that can be cre-
ated using the unit’s sliders, signals outside the audio band can be controlled by
using in the low cut and high cut filters.
SOUND REINFORCEMENT APPLICATIONS
There are many applications for the EQ2015 & EQ2030 in professional sound rein-
forcement or “PA” systems. The most popular use of the EQ2015 & EQ2030 is to
provide 2/3 & 1/3 octave equalization of the main or monitor speaker systems to
correct response errors in the speakers compensate for room acoustics and con-
trol feedback. For feedback control, a good technique is to raise the level of the
system to the threshold of the threshold of feedback (i.e. to the point where the sys-
temjust begins to ring) and then locate the slider that controls the “ringing” frequency.
Reduce the level of that slider until the ringing is eliminated. Again increase the
overall monitor level until the system just begins to ring (at a new frequency) and
repeat the sequence until 3 or 4 frequency are ringing together. At this point you
have reached your lowest feedback setting.
An appropriate place to insert the EQ into the system is between the outputs of
the mixer or monitor main and the inputs of the power amplifier. In addition to using
the EQ2015 & EQ2030 to equalize loudspeaker frequency response, the units can
be used as a program equalizer on individual channels or subgroups to establish
optimum tonal balance. In the latter case the EQ would be patched into the appro-
priate channel or subgroup at the console.
The low cut sweepable filter constitutes an excellent sub-sonic filter and can pro-
vide a high degree of protection to the woofers in a sound system for unexpected
sub-sonic transients (such as might result from a dropped microphone, intermit-
tent connection, or other audio hazzards associated with live sound). The low-cut
filter will also help conserve amplifier power and reduce woofer cone excursion so
that higher sound pressure levels can be achieved before running out of amplifier
headroom. A recommended setting is 35 Hz. The hi-cut filter can provide a degree
of protection to high frequency horns or tweeters from inaudible ultrasonic oscil-
lations in system components ahead of the EQ2015 & EQ2030. A recommended
setting is 20k Hz.
HOME HI-FI APPLICATION
The EQ2015 & EQ2030 are excellent equalizers for home Hi-Fi use. Those audio-
phyles who appreciate professional grade audio equipment will appreciate the value
these equalizers represent in addition to the professional quality they provide.
The primary application of a 2/3 & 1/3 octave graphic equalizer in a home Hi-Fi
system will likely be to establish a highly accurate frequency response in the lis-
tening room. In this case the equalizers can be interfaced at the tape monitor of
the systems “receiver” or “pre-amp”. The equalizer can also be inserted between
the stereo pre-amp and stereo power amp of a system with separate pre and power
amps. For the case of a typical Hi-Fi stereo receiver the left and right “tape outputs”
would be connected (by way of an appropriate cable) to the inputs (most likely by
way of the 1/4” phone jacks). The outputs of the units could then be connected
back into the left and right “tape inputs” of the stereo receiver. Depressing the “tape”
switch on the receiver would then connect the EQ into the system.
Other home Hi-Fi applications for the EQ2015 & EQ2030 are those relating to home
recording. Connecting the EQ between the preamp output and the tape recorder
input allows equalization of the material being recorded. This configuration could
be used to make tape dubs of older recordings with equalization according to your
own musical taste.
Figure 1.
1642
MONITOR POWER AMP
LEFT & RIGHT
MAIN SPEAKERS
MONITOR SPEAKERS
MAIN EQ 2030
CHANNEL TWO
10K
6K 45K
35K
25K
20
10 230
120
50
EQ IN
dB
+6
0
GAIN
PEAK
HI CUT
Hz
LOW CUT
Hz
0dB
+15
–15
CHANNEL ONE
ON
OFF
EQ2015
25 40 63 100 160 250 400 630 1K 1.6K 2.5K 4K 6.3K 10K 16K
10K
6K 45K
35K
25K
20
10 230
120
50
EQ IN
dB
+6
0
GAIN
PEAK
HI CUT
Hz
LOW CUT
Hz
0dB
+15
–15
25 40 63 100 160 250 400 630 1K 1.6K 2.5K 4K 6.3K 10K 16K
–3
+3
–6
+6
–3
+3
–6
+6
EQ2030
ON
OFF
CHANNEL TWO
0dB
+15
–15
25 31.5 40
–3
+3
–6
+6
50 63 80 100 125 160 200 250 315 400 500 630 800 1K 1.25K 1.6K 2K 2.5K 3.15K 4K 5K 6.3K 8K 10K 12.5K 16K 20K
0dB
+15
–15
25 31.5 40
–3
+3
–6
+6
50 63 80 100 125 160 200 250 315 400 500 630 800 1K 1.25K 1.6K 2K 2.5K 3.15K 4K 5K 6.3K 8K 10K 12.5K 16K 20K
EQ IN
10K
6K 45K
35K
25K
20
10 230
120
50
dB
+6
0
GAIN
PEAK
HI CUT
Hz
LOW CUT
Hz
CHANNEL ONE
EQ IN
10K
6K
45K
35K
25K
20
10
230
120
50
dB
+6
0
GAIN
PEAK
HI CUT
Hz
LOW CUT
Hz
MONITOR EQ 2015
MAIN
LEFT / RIGHT
OUTPUTS
MONITOR 1/2
OUTPUTS
MIXER
INPUTS
MAIN POWER AMP