DBX 3031 User Guide

¥ 31 ISO standard center 1/3 octave

constant Q frequency bands

¥ Variable high pass and switchable

low pass 12dB/octave filters

¥ Electronically balanced inputs,

servo balanced outputs

¥ XLR, barrier strip, and TRS con-

nectors
¥ Switchable 6 or 12dB boost/cut
¥ -12/+15dB of input gain

¥ Passive bypass removes equalizer

from signal path when power is off

¥ 8 segment LED headroom bar

graph
¥ Chassis ground lift capability
¥ Toroidal power supply transformer

®

XLR, barrier strip, and 1/4 inch tip-ring-sleeve connectors make the unit easy to integrate into any type
of balanced or unbalanced audio system.

Housed in a rugged 2U EIA standard 19" cold-rolled steel chassis, the 3031 will stand up to years of
abuse, making it a valuable asset for permanent installations or touring companies.

Recording studios, broadcast facilities, sound reinforcement engineers, musicians, and sound contrac­tors alike will find that the straightforward design and versatile signal control options make the 3031 a
powerful audio tool.

dbx uses only the highest quality, low tolerance components, ensuring excellent reliability and uncom­promising sound quality. From permanent installations to sound contracting, critical audio to sound
reinforcement, the dbx 3031 delivers total performance.

The dbx 3031 Graphic Equalizer is a high performance multifunctional unit designed to deliver all the
flexibility and power that professional users demand. Featuring long-throw precision sliders, switch­able high- and low-pass filters, balanced / unbalanced connectors, and ultra low-noise performance, the
3031 is more than equal to any critical audio task requirements. The 3031 offers 31 ISO standard cen­ter, 1/3 octave constant Q frequency bands in a single package. Selectable 6 or 12dB of boost/cut gives
the user superior signal processing control, while the use of low tolerance components yields accurate
frequency centers. Features variable high pass and switchable low pass filters. The unit also includes a
passive bypass system that completely removes the equalizer from the audio path when power is off.
Also included is an active bypass that allows comparison of the equalized signal with the original.

8760 S. Sandy Pkwy.

Sandy, Utah 84070

Phone [phone]

Fax [phone]

IntÕl Fax [phone]

[e-mail]

http://www.dbxpro.com

A Harman International Company

GRAPHIC EQ

1/3 OCTAVE

3031

+6

0

-6

42

Headroom (dB)

125

IN

OUT

HI CUT

OUT

LO CUT

-12

Power

200

Hz

25

LO CUT

20 25 31.5 40 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

+12

3

0

6

0

36

30

24

18

12

+6-6

+12

63

dB

dB

LEVEL

32

-12

IN

IN

OUT

12 dB

6 dB

EQ

RANGE

FOR MORE INFORMATION CONTACT:

dbx Professional Products

8760 S. Sandy Pkwy.

Sandy, Utah 84070

Phone [phone]

Fax [phone]

IntÕl Fax [phone]

[e-mail]

http://www.dbxpro.com

The graphic equalizer shall have one channel, with an audio frequency
response of 20Hz to 20kHz, ±0.1dB, an unbalanced input impedance
of not less than 50k½ and a balanced input impedance of not less than
75k½ with a maximum input level of not less than +22dBu. The unit
shall have rear panel 1/4" TRS phone jacks, barrier strip and XLR jacks
for inputs and outputs, accepting either balanced or unbalanced signals.
The output impedance shall be no more than 100½ balanced, 50½
unbalanced with a maximum output level of not less than +22dBu into
an unbalanced or balanced load with a minimum load impedance of not
more than 600½. Total Harmonic Distortion plus Noise shall not be
more than 0.003% at +4dBu input level and 1kHz, all faders flat. The
unit shall have a Noise level of not more than -92dBu at the ±6dB
boost/cut range setting with all faders flat across a test bandwidth of
22Hz to 22kHz. The unitÕs operating dynamic range shall be not less
than 114dB.

The unit shall have 31 constant Q frequency band filters with center
frequencies on 1/3 octave ISO standard centers ranging from 20Hz to
20kHz; a High Pass filter with a 12dB per octave slope and a selectable
corner frequency with a range from 25Hz to 200Hz; and a Low Pass
filter with a 12dB per octave slope and a corner frequency of 15kHz.
Each of the unitÕs 31 filter bands shall be controlled by front panel,
45mm linear sliders with a maximum boost per frequency band of not
less than +12dB and a maximum cut per band of not more than -12dB.
There shall also be a master attenuator for each channel with a range from -12dB to +15dB. The unit shall have a front
panel Power switch and the following controls: range selector switch for either ±6dB maximum cut and boost or ±12dB
maximum cut and boost per band; EQ In/Out switch; High Cut Filter In/Out switch; Low Cut filter In/Out switch. The
following front panel indicator LEDs shall exist: Power, and Headroom Level (8) at 3, 6, 12, 18, 24, 30, and 36dB. The
unit shall have separate chassis and signal ground lift lugs on the rear panel, a relay bypass and be capable of accepting
the optional installation of certain specified input and output transformers. The power requirements shall be 100, 120,
230, 240VAC, 50/60Hz, at 30 watts via a detachable IEC type AC cable. The 2U high, full rack width graphic equaliz­er shall be a dbx 3031.

dbx engineers are constantly working to improve the quality of our products. Specifications are, therefore subject to
change without notice.

Frequency Response: 20 Hz to 20 kHz, ±0.1

dB (all faders flat)

Control Centers: 31 ISO Standard, 1/3

octave bands per chan­nel from 20 Hz to 20
kHz: 20, 25, 31.5, 40,
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, and
20k.

High Pass Filter (LO CUT): 12 dB/octave, vari-

able from 25 Hz ­200 Hz.

Low pass filter (HI CUT): 12 dB/octave,15

kHz.

Nominal Control Range: ±6 dB or ± 12 dB

cut/boost

Noise Level: <-92 dBu @ ±6 dB

boost/cut range (faders
flat, test bandwidth 22
Hz to 22 kHz)

Input Impedance: 75K ohms balanced,

50K ohms unbalanced

Maximum Input Level: +22 dBu (ref.:0.775

Vrms)

Output Impedance: 100 ohms balanced, 50

ohms unbalanced

Maximum Output Level: +22 dBu (ref.:0.775

Vrms)
Dynamic Range: 114 dB
Headroom Indicator: 3 to 42 dB, 8 seg-

ments.

THD + Noise: <.003% (at 1 kHz, +4

dBu input, test band­width 22 Hz to 22 kHz).

Power Requirements: 100, 120, 230, 240

VAC 50/60 Hz, 30
watts

Dimensions: 7.9" x 3.5" x 19"

(D) (H) (W)

Weight: 8.5 lbs

3031

SINGLE CHANNEL 31 BAND GRAPHIC EQUALIZER

3
6

+7-6

12
18
24
30
36
42

125

Headroom (dB)

Power

GROUND LIFT

RANGE

HI CUT

LO CUT

0

IN

OUT

EQ

12 dB

+15

-12

dB

dB

6 dB

GAIN

IN

63

32

OUT

IN

OUT

25

200

Hz

LO CUT

+12

0

-12
20 25 31.5 40 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

CAUTION:

TO REDUCE
THE RISK OF FIRE REPLACE
ONLY WITH SAME TYPE FUSE.

ATTENTION:

UTILISER
UN FUSIBLE DE RECHANGE DE
MEME TYPE.

ATTENTION:
WARNING:

SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR

TO REDUCE THE RISK OF FIRE OR ELECTRIC

OUTPUT INPUT

®

+6

CONNECTOR POLARITY

OUTPUT

-GND +

PHONE:
TIP
RING
SLEEVE

INPUT

XLR:
PIN 1
PIN 2
PIN 3

-GND +

0

-6

PROFESSIONAL PRODUCTS

A HARMAN INTERNATIONAL COMPANY

INPUTOUTPUT

INPUT

GROUND

LIFT

SALT LAKE CITY, UTAH

MADE IN USA

®

3031

1/3 OCTAVE

GRAPHIC EQ