Precision Power PRECISIONPOWER DEQ-230 - Manual (Page 9)

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The DEQ-230 Equalizer puts an incredible amount of control in your hands. Correctly
adjusted, it can solve many of the problems you will encounter along your road to perfect
sound. Incorrectly adjusted, it can cause just as many problems. By following these
guidelines, you will avoid common pitfalls in system tuning and get your sound quickly
dialed in. We recommend that you use a Real Time Analyzer (RTA) to speed things up, but
it is possible to tune your system without it.
1) With the system turned OFF, remove the control panel from the chassis of the
DEQ-230, replace the short connecting cable with the 20' cable, and take the control
panel to the adjusting location (either inside the car or next to the RTA).
NOTE: If you are using a Real Time Analyzer (RTA), go to step 2. If not, go to step 8.
2) The first step is to locate a suitable source of “pink noise.” A good choice would be
the current IASCA competition reference disc. Also, some RTAs have a built-in pink
noise source. Ideally, the pink noise should play through your head unit, allowing you
to compensate for any frequency response changes caused by it, or anything else,
before the amplifiers.
3) Next, place the microphone from the RTA in the driver's seat at approximately head
level. Initially, set the analyzer to read at 3dB per step, and set the speed of the
RTA’s readout to "medium." Turn on your system and start the pink noise.Raise or
lower the volume until you can see all (or most) of your frequency response on the
RTA scale (a little above or below is OK). Make sure all of the equalizer's frequency
controls are at zero and look at the RTA screen.
4) You are trying to achieve a target frequency response, or "curve" that reflects
your preference. You might think that a perfectly straight line would be best, but
it really doesn't sound very good. Instead, shoot for a curve that starts about
9dB up at the low frequencies (25Hz to about 100Hz) dropping gently to 0dB
in the midrange (250Hz to 3KHZ), then dropping gently to -9dB at 16KHZ and 20KHz.
5) If electronic crossovers are used, any large frequency sections corresponding to
your crossover points that are low or high should be brought in line using crossover
level controls or amp gain adjustments, not with the equalizer.
6) Beginning at either the lowest or the highest frequency, adjust the control on the
DEQ-230 that corresponds to a large peak or dip on the RTA display until it moves
into line with adjacent frequencies. Move to the next frequency and repeat until you
run out of frequencies to adjust. Try to remove the peaks before filling the dips.
Periodically, while you are making adjustments, compare the new curve you are
making to the system in an unequalized state by using the defeat switch on the lower
left corner of the control panel. This allows you to compare your original starting
point to the present state of equalization in the system.