Precision Power EQ-31 Owners Manual

Thank you for choosing

PPI

audio epuipment. Now, HANG ON!

PPI

products are engineered and manufactured to deliver a wild ride of
performance, sound quality , and reliability . This

PPI

product reflects our com­mitment to offer you versatility and quality for years of incredible power and
listening enjoyment!

SERVICE

Do not attempt to service

PPI

products yourself. Performing exploratory
surgery on your audio equipment yourself will void the warranty. All parts of
your

PPI

gear have been built to our specifications. These parts are not made

available to any unauthorized

PPI

dealer nor are they for sale. Our goal is to

make sure that your

PPI

product will always perform as good as the day it

was purchased. Contact your authorized

PPI

dealer about obtaining any war-

ranty service through

PPI

. (See Warranty inside back cover.)

CAUTION!

The extended use of a high powered audio system may result in hearing loss
or damage. While

PPI

systems are capable of "Concert Level" volumes, they
are also designed for you to enjoy at more reasonable levels all of the cre­ative expressions made by musicians. Please stay seated while driving and
observe all local sound ordinances.

Stereo/Mono 1/3 Octave Equalizer
30 Center Controls with ±12dB gain
Balanced Differential Input Stage
Input Attenuation Switch
Mono/Stereo Switch
Defeat Switch
Gold RCA input and output connectors
PWM Power Supply
Designed and Handcrafted in the USA

Signal-to-Noise Ratio >102dB
Total Harmonic Distortion (1KHz, 1VRMS) 0.017%
Boost/Cut Range ±12dB
Maximum Input Voltage (EQ Defeated) 4Vrms
Maximum Output Voltage 8Vrms
Supply Voltage 11-15 VDC
Frequency Centers 25Hz, 31.5Hz, 40Hz, 50Hz, 63Hz,

80Hz, 100Hz, 126Hz, 156Hz,
200Hz, 250Hz, 320Hz, 400Hz,
500Hz, 635Hz, 800Hz, 1KHz,

1.27KHz, 1.6KHz, 2KHz, 2.5KHz,

3.2KHz, 4KHz, 5KHz, 6.4KHz, 8KHz,
10KHz, 12.8KHz, 16KHz, 20KHz

Dimensions 7.500”L

7.875”W

1.000”H

1

2

To prevent damage to the equalizer while driving, mount it in a secure
place. Choosing the appropriate location will depend upon your vehicle and
the complexity of your system design. Typical mounting locations include the
trunk and passenger compartment (floor or under seat). Never mount the
equalizer in a location that would subject it to immersion or exposure to water.

Once a location has been chosen, securely mount the

PPI-EQ-31

with four
mounting screws. Be Careful! Inspect the area underneath to be sure you are
not drilling into wires, brake or fuel lines, etc. that could be damaged by the
drill bit or screws.

Holes for mounting screws

3

80Hz

63Hz

40Hz

31.5Hz

320Hz156Hz 635Hz

250Hz126Hz 500Hz

50Hz25Hz 200Hz 100Hz 400Hz

10KHz

8KHz

1.27Hz 2.5KHz 5KHz

2KHz1KHz 4KHz

20KHz

16KHz

6.4KHz800Hz 1.6KHz 3.2KHz 12.8KHz

GND

REM

+12V

OUTPUT
L

R

INPUT

LR

-12db

MONO

DEFEAT

PPI•EQ31

1/3 octave crossover

Before beginning, disconnect the negative (-) terminal of the battery prior
to working on the positive (+) terminal to prevent a short to ground.
This is important, unless you want to spend the rest of your life with a
nickname like "Sparky," or "Smokey." Reconnect the negative terminal
only after all connections have been made.

4

The next step is to connect the Power, Ground, and Remote wires to your

PPI-EQ31

. The power wire should run from the mounting location through
the vehicle to the battery or power distribution block. Avoid sharp corners,
creases, and sharp body parts. When passing through any metal wall (i.e.
firewall etc.), a grommet must be used to prevent the wire from chaffing and
shorting to ground.

The ground wire should be of
the same gauge as the power
wire. As a rule of thumb, use
as short a length of wire as
possible.

Find a location near the
equalizer that is metal (the floor
is ideal) and clean an area about
the size of a quarter to bare
metal. Drill a pilot hole in the
middle of this area. Be Careful!
Inspect the area underneath to
be sure you are not drilling into
wires, brake or fuel lines, etc.
Terminate the wire with a ring
connector and attach it to the
bare metal using a #8 sheet
metal screw and washer (not supplied). We suggest crimping and/or
soldering this connection. After the connection is complete, coat the area with
silicone or some similar material to prevent rust from developing.

Finally, the remote wire needs to run to the power antenna (or amplifier
remote) lead of the head unit. This wire supplies a 12 volt signal to the

PPI-EQ31

when the main system is activated.

Once you have routed the power, ground, and remote wires through the
vehicle, it is time to connect the wires to the

PPI-EQ31

. Be sure that you

have not reconnected the ground cable to the negative post of the battery.

Cut off excess wire and, using wire strippers, strip the power, ground and
remote cables about 1/8 inch. Locate the power, ground, and remote

Power

Lock

connector (supplied). On the top of the connector are three slot­ted screws. With a small flat-bladed screwdriver, loosen the screws before
attempting to insert the cables. After you have inserted the stripped end of
each cable into the connector, secure it by tightening the associated screw.
Check that each connection is tight. If the wires are secure, the connector
may be plugged into the

PPI-EQ31

.

T/O

B+

5

1. Input

Connect RCA cables from your head unit here.

2. -12 dB

Push this switch in to accept high level RCA inputs
(up to 8 volts) or direct speaker lead inputs from common
grounded (not high powered) headunits.

3. Mono

Push this switch IN to send left input to both channels
of the EQ-31 for Mono operation. Leave the switch out
for stereo operation.

4. Defeat

Push this switch IN to bypass the EQ-31

5. Output

Connect RCA cables to your Preamp, Crossover or
Amplifier here.

6. Power/Remote

After connecting Ground, Remote, and Power wires plug
in the

PowerLock

connector here.

2 3 4

5

61

The

PPI-EQ-31

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.

NOTE:

If you are using a Real Time Analyzer (RTA), Start Here.
If not, go to step 7.

1) 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.

2) 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.

3) 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.

6

4) 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.

5) Beginning at either the lowest or the highest frequency, adjust

the control on the

PPI-EQ-31

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 Input Endplate of the control panel. This allows
you to compare your original starting point to the present
state of equalization in the system.

6) Play your favorite music. If the sound isn’t what you’re looking
for, go back to the pink noise and smoothly adjust your
curve for more bass, less midrange or whatever you think will
correct the sound. Remember that this is your system don’t
let someone else tell you how it should sound! When the
sound is close to what you want, move to step 8.

7) Play several different music tracks. If you hear an instrument
or voice, or other sound that is too loud, find the sound on
the chart on page 9. This will give you clues as to what
frequencies need to be adjusted on the

PPI-EQ-31

. (If you
have already tuned using an RTA, this step is icing on the
cake.)

7

electric guitar

acoustic guitar

violin

cello

double bass

trumpet

french horn

trombone

tuba

soprano sax

tenor sax

clarinet

oboe

flute

piano

synthesizer

female vocal range

male vocal range

tympani

kick drum

tom drum

snare drum

cymbals

electric bass

FUNDAMENTAL NOTE

HARMONIC OR OVERTONE

25 50

100

200 400 800 1.6 3.2 6.4 12.8 20K

8

9

80Hz

63Hz

40Hz

31.5Hz

320Hz

156Hz

635Hz

250Hz

126Hz

500Hz

50Hz

25Hz

200Hz 100Hz

400Hz

10KHz

8KHz

1.27Hz 2.5KHz

5KHz

2KHz

1KHz

4KHz

20KHz

16KHz

6.4KHz

800Hz

1.6KHz

3.2KHz

12.8KHz

GND

REM

+12V

OUTPUT
L

R

INPUT

L R

-12db
MONO

DEFEAT

PPI•E Q31

1/3 octave crossover

10

11

DIF

-12dB INPUT ATTENUATION

RCA

Right Input

RCA

Left Input

Stereo / Mono

Switch

Right Output

DIF

30 BAND EQUALIZER

30 BAND EQUALIZER

Left Output

EQ / Bypass

Switch

This warranty gives you specific legal rights, and you may also have other rights which vary from
state to state. PrecisionPower, Inc. (PPI) warrants its products to be free from defects in materials
and workmanship under normal use and service for a period of three (3) years from the date of
original purchase when the unit is installed by an Authorized Dealer. Non-Authorized Dealer installed
products carry a one (1) year parts and ninety (90) days labor limited warranty. The extent and con­ditions of Limited Warranty are as follows:

1. Authorized Dealer Installed Products: PPI will either repair or replace at no charge, to the
original purchaser, any unit which PPI’s examination discloses to be defective and under warranty,
provided the defect occurs within three (3) years from the date of original purchase when the unit is
installed by an Authorized Dealer and the product is returned immediately to PPI. This warranty is
not transferable.

2. Non-Authorized Dealer Installed Products: PPI will either repair or replace at no charge, to the
original purchaser, any unit which PPI’s examination discloses to be defective and under warranty,
provided the defect occurs within ninety (90) days from the date of purchase and the product is
returned immediately to PPI. Warranty claims beyond ninety (90) days for Non-Authorized Dealer
Installed Products will be for parts only and will extend for one (1) year from the date of purchase.
This warranty is not transferable.

3. The date of purchase and proof of Authorized Dealer Installation of a PPI product must be
established by an original sales receipt which must accompany the article being returned for
warranty work.

4. This warranty shall NOT apply to any PPI product found to have the original factory serial
number removed or defaced. All products received (by PPI) for in warranty or out of warranty repair,
with their original serial numbers removed or defaced, will NOT be repaired and will be returned
to sender, freight collect. Refer to original packaging for the serial number of your component speak­ers.

5. The provisions of this warranty shall not apply to any PPI product used for a purpose for which it
is not designed, which has been repaired or altered in any way, or which has been connected,
installed, or adjusted other than in accordance with the instructions furnished in PPI’s owner’s
manual. Nor shall this warranty apply to any part which has been subject to misuse, neglect, or acci­dent.

6. PPI does not authorize any other persons to assume any other liability in connection with its prod­ucts. THIS WARRANTY IS THE ONLY EXPRESS WARRANTY MADE BY PRECISIONPOWER
APPLICABLE TO ITS PRODUCTS. ANY IMPLIED WARRANTY OR MERCHANTABILITY OR
FITNESS FOR APARTICULAR PURPOSE APPLICABLE TO PRECISIONPOWER PRODUCTS IS
LIMITED IN DURATION TO THE DURATION OF THIS LIMITED WARRANTY. PRECISIONPOW­ER SHALLNOT BE LIABLE FOR THE INCIDENTAL, CONSEQUENTIAL, OR COMMERCIALDAM­AGES RESULTING FROM THE BREACH OF THIS WRITTEN WARRANTY. Some states or
provinces do not allow the exclusion or limitation of incidental or consequential damages or limita­tions on how long an implied warranty lasts; so the above limitations or exclusions may not apply to
you.

7. Your product will be serviced on an in-warranty basis within the warranty period for the
correction of warranted defects. If improper operation of your PPI product should occur, contact your
Authorized Dealer for assistance with the return and factory repair of your PPI product. If an
Authorized Dealer is not available, return the unit including your name, telephone number, return
address, a copy of your sales receipt, and a description of the problem to:

Precision

Power

, Inc.

Service Department
4829 S. 38th Street

Phoenix, AZ 85040-2964

TO RETURN PPI PRODUCTS OUT OF WARRANTY: Return the unit, postage
prepaid, in the original protective carton. Please include a description of the
problem and, if desired, a request for an estimate of repair costs. Unless a
request for an estimate is included, the unit will be repaired as necessary.
Please contact PPI Customer Service at 1-800-62-POWER for questions
concerning out of warranty repair charges. Repaired unit will be returned with
an itemized statement, C.O.D.