Lowell EQ1 - Manual (Page 5)

Instruction Sheet
IS-EQ1
Issued: 1-20-14
Lowell Manufacturing Company 100 Integram Drive Pacific, Missouri 63069 U.S.A.
Call: 800-325-9660 Fax: 636-257-6606 Click: www.lowellmfg.com
5
Setting Gain Structure
Here is one method of setting your equalizer gain that works well. Begin with the following settings:
1. Engage the BYPASS switch. (switch depressed, bypassed and LED is on.)
2. Put all sliders in their center position (0 dB). Note: All sliders have a detent at the center 0dB position.
3. Position the LEVEL
control about “6” for unbalanced operation and “7” for balanced operation.
4. Apply a signal to the system.
5. Verify the OL LED is not on
—occasionally blinking during extreme peaks indicates an optimal setting. But if it
lights up a lot or lights steadily, lower the output level of the previous device in the signal chain.
6. Release the BYPASS switch and begin adjusting the equalizer filters. Note: For insight into a method of
using the equalizer to tune a sound system or a sound masking system, see the following three sections.
7. During filter band adjustments, if the OL LED lights more than occasionally, turn down the output of the
previous device in the signal chain. Run the EQ1 with an input signal that is as hot as possible without the OL
lighting more than occasionally.
8. Insuring the proper level of gain though the EQ1 is just as important as adjusting the equalizer bands.
Improper gain distribution is a common cause of loss of system headroom and less than optimum noise
performance. The BYPASS switch allows comparison of equalized versus un-equalized signal. It is also useful
in adjusting the level of the EQ1 for unity gain which results in the best signal-to-noise performance. When the
gain is not properly adjusted,
the level difference between the equalizer “bypassed” or “in the circuit”, can be
significant. Once all filter bands are adjusted to your liking, adjust the LEVEL control on the EQ1 so there is no
difference in overall level with the BYPASS switch in the bypassed position (pushed in and LED on) compared
to with the BYPASS switch in the active position (not pushed in and LED off).
9. The last step is to reconfirm one last time that the OL LED lights only when there are large signal spikes in
the program material. If the OL LED lights up a lot or lights steadily, lower the output level of the previous
device in the signal chain.
EQ1 Connection
INPUTS
Both the XLR and ¼" TRS inputs are wired in parallel and are actively balanced. Each works equally well.
Choose strictly from a required hardware point-of-view, there will be no performance trade-offs. The wiring
convention adheres to American, British and International standards of pin 2 or tip being hot, pin 3 or ring being
return, and pin 1 or sleeve being shield. Unbalanced operation involves using only pin 2 or tip as signal, and pin
1 or sleeve as shield or ground. It is not necessary to short any inputs to ground for unbalanced operation. It
doesn’t hurt. It’s just not necessary. Use pin 1, or the shell, for shield ground.
OUTPUTS
Balanced output requires using pin 2 or tip, and pin 3 or ring for the signal. It does not require pin 1 or shield.
The signal exists differentially between the two balanced leads; ground is not involved. To insure a hum-free
system, use the ground pins only for shielding.
EXPANDING
Expanding and/or daisy-chaining the inputs and outputs normally uses the ¼" jacks. The parallel input connect-
ors allow driving a second EQ1 without special cabling. Simply connect the feed for the first EQ1 to the XLR
balanced input.
Use a ¼” TRS phone plug jumper cord to connect the ¼” TRS input jack on the first EQ1 to the
¼” TRS input jack on the second EQ1 and both units will be fed with the same input signal. A similar thing can
be done with the output wiring. The balanced XLR output can feed to one amplifier,
and the ¼” TRS phone jack
output can feed to a separate amplifier or the input of some other device.
SIGNAL LEVELS
Input signal levels from -10 dBV to +4 dBu are considered normal and within range (at least 20 dB of headroom
exists above these levels). Do not connect microphones directly to the input of the EQ1. Microphones require
an external mic preamp. The EQ1 requires a line level input signal.
Operating Instructions