DOD SR231Q User manual
GRAPHIC EQUALIZER
SR231
Dual 31-Band Constant Q Equalizer
The DOD SR231Q is a powerful 2 rack space
stereo/dual mono 31-band graphic equalizer of
uncompromising quality, performance, and features.
It allows the user to see a graphic representation of
equalization applied to the audio spectrum of a
sound source, and offers the flexibility to provide
solutions to many EQ problems. The SR231Q offers
up to 12 dB of cut or boost per band, and switch-
able low cut filters for each channel. Electronic fil-
ter switching minimizes transients (loud pops or
clicks when the switch is depressed), and up to
±12 dB of level control is available to compensate
for gain changes due to equalization boost or cut.
Constant Q constant bandwidth from each filter
throughout the full audio spectrum. The SR231Q
can be used as a stereo equalizer or as two inde-
pendent channels of equalization, providing maxi-
mum flexibility for all sound systems. Connections
to the SR231Q may be either impedance balanced
(1/4" tip-ring-sleeve phone plug) or unbalanced
(mono 1/4" phone plug) with XLR connectors avail-
able as a factory option.
Low Cut Filter: 12 dB/octave rolloff, 3 dB down @ 50 Hz,
switchable in or out.
Frequency Response: 20 Hz-20 kHz, ±0/-0.5 dB.
Frequency Center Tolerance: 5%.
Slider Control Range: 12 dB cut/boost.
Input Impedance: 40kΩbalanced, 20kΩunbalanced.
Maximum Input Level: +21 dBu.
Output Impedance: 102Ωbalanced, 51Ωunbalanced.
Maximum Output Level: +21 dBu.
Input Gain Control: ±12 dB.
Harmonic Distortion: 0.004% at 1 kHz typical.
Signal-To-Noise Ratio: Greater than 90 dB.
Note: 0 dBu = 0.775 Vrms.
Input Common Mode Rejection: >75 dB@60Hz
SPECIFICATIONS
• 31 1/3 Octave Standard ISO Center
Frequencies Bands per channel
• Constant Q Filter
• 12dB of Boost/Cut per Band using Low
Noise Potentiometers
• LED Bargraph Level Indicators
• Low Cut and EQ In/Out Switches with
LED Indicators
• Balanced/Unbalanced input and
impedance bal/unbal outputs for each
channel
• Front Panel Power Switch
• 1/4" Phone connectors (XLR Optional)
• 2 Unit Rack Space
• OneYear Limited Warranty
A Harman International Company
8760 South Sandy Parkway, Sandy, Utah 84070 • (801) 566-8800 • Fax (800) 333-7363 • Int'l Fax (603) 672-4246 • Visit DOD on the World Wide Web at www.dod.com
GRAPHIC EQUALIZER
SR231
The graphic equalizer
shall be a two-channel 31-
band type with frequency
centers on standard ISO
one-third octave frequen-
cies with 12 dB of boost
and cut for each slider.
Equalization sliders shall
have a center detent at 0
dB with a protective dust
cover behind the front
panel. Low-noise sliders
shall be utilized having a
travel of 20 mm. Each
channel shall have a slider
input gain control with +/-
12 dB range with center
detent at 0 dB. Bypassing
each EQ channel shall be
accomplished by a front-
panel switch utilizing elec-
tronic FET switching to
avoid transients and shall
have an LED to indicate
that the EQ is in. A front-
panel low-cut filter per
channel at 50 Hz with 12 dB/
octave slope shall incorpo-
rate electronic FET switch-
ing and shall have an LED to
indicate that the filter is
engaged. Output level shall
be monitored on each channel by a four-LED peak-reading bar graph
calibrated to read -10, 0 +10, and +17 dBu.
The input section shall have one input per channel—electronical-
ly balanced/unbalanced 1/4" TRS jacks (optional electronically bal-
anced/unbalanced 1/4" TRS and XLR jacks) The output section shall
have one output per channel—impedance balanced/unbalanced 1/4"
TRS jacks (optional impedance balanced/unbalanced 1/4" TRS and bal-
anced XLR jacks).
A front-panel rocker-type power switch shall provide visual indi-
cation with red marking. The power supply shall be internal with two
thermally-fused transformers mounted in low hum orientations. The
transformers and primary side of the power supply shall be isolated
from the secondary and electronics by means of a steel hum isolation
shield. The power cord shall be detachable from an international stan-
dard IEC 320 power inlet receptacle. Unit shall be constructed to
meet or exceed all applicable international safety and regulatory agen-
cies. Unit shall be powered from 120 VAC 60 Hz (or 100 VAC 50/60
Hz, 230 VAC 50 Hz, 240 VAC 50 Hz). Unit housing shall be of all steel
construction and shall be rack-mountable in an IEC standard 19" rack
and shall occupy a 2U (3.5") rack space. An optional security cover
must be available.
The unit shall be a DOD SR231Q (or SR231QXLR) Graphic
Equalizer.
SR231Q
Notes
ARCHITECT & ENGINEER SPECIFICATIONS
#18-1701-A
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