Directed Audio 350d User manual

model
350d

TABLE OF CONTENTS
CONGRATULATIONS
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© 2003 Directed Electronics, Inc
Limited Two-Year Consumer Warranty . . . . . . . . . . . . . . . . . . . . . . . . .3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Warning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Installation Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Front Panel Connections/Controls . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Rear Panel Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Speaker Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Crossover Settings and Gain Adjustment . . . . . . . . . . . . . . . . . . . . . . .10
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Congratulations for choosing a Directed
Audio power amplifier from Directed
Electronics, the industry leader in high
quality automotive security and audio
equipment since 1990.
Directed Audio power amplifiers
continue to set new standards of perfor-
mance, reliability, and affordability in
the mobile electronics industry.
Featuring high-efficiency MOSFET power
supplies, flexible on-board crossovers,
and state of the art audio design,
Directed Audio power amplifiers will
excite and delight the mobile sound
enthusiast with years of high-quality
audio reproduction.
Directed Audio power amplifiers come
with a two-year limited warranty if
installed by an authorized Directed
dealer. If not installed by an authorized
dealer, Directed Audio power amplifiers
are covered by a one-year, parts-and-
labor limited warranty.
Be sure to retain your original sales
receipt and refer to the warranty section
of this guide for full details about your
coverage.

LIMITED TWO-YEAR CONSUMER WARRANTY
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© 2003 Directed Electronics, Inc
Directed Electronics, Inc. promises to the
original purchaser, to replace this product
should it prove to be defective in workman-
ship or material under normal use, for a
period of two years from the date of
purchase by the dealer as indicated by the
date code marking of the product
PROVIDED the product was installed by an
authorized Directed dealer. During this two-
year period, there will be no charge for this
replacement PROVIDED the unit is returned
to Directed, shipping pre-paid. If the unit is
installed by anyone other than an autho-
rized Directed dealer, the warranty period
will be 1 year from the date of purchase by
the dealer as indicated by the date code
marking of the product. During this 1-year
period there will be no charge for this
replacement PROVIDED the unit is returned
to Directed, shipping pre-paid. This warranty
is non-transferable and does not apply to
any unit that has been modified or used in a
manner contrary to its intended purpose,
and does not cover damage to the unit
caused by installation or removal of the unit.
This warranty is void if the product has been
damaged by accident or unreasonable use,
neglect, improper service or other causes
not arising out of defects in materials or
construction. ALL WARRANTIES INCLUDING
BUT NOT LIMITED TO EXPRESS
WARRANTY, IMPLIED WARRANTY,
WARRANTY OF MERCHANTABILITY,
FITNESS FOR PARTICULAR PURPOSE, AND
WARRANTY OF NON-INFRINGEMENT OF
INTELLECTUAL PROPERTY ARE EXPRESSLY
EXCLUDED TO THE MAXIMUM EXTENT
ALLOWED BY LAW, AND DIRECTED
NEITHER ASSUMES NOR AUTHORIZES
ANY PERSON TO ASSUME FOR IT ANY
LIABILITY IN CONNECTION WITH THE
SALE OF THE PRODUCT. DIRECTED HAS
ABSOLUTELY NO LIABILITY FOR ANY AND
ALL ACTS OF THIRD PARTIES INCLUDING
ITS AUTHORIZED DEALERS OR
INSTALLERS. Unit must be returned to
Directed, postage pre-paid, with: consumer’s
name, telephone number, and address,
authorized dealer’s name and address, and
product description. IN ORDER FOR THIS
WARRANTY TO BE VALID, YOUR UNIT
MUST BE SHIPPED WITH PROOF OF
INSTALLATION BY AN AUTHORIZED
DIRECTED DEALER. ALL UNITS RECEIVED
BY DIRECTED FOR WARRANTY REPAIR
WITHOUT PROOF OF DIRECTED DEALER
INSTALLATION WILL BE COVERED BY THE
LIMITED 1-YEAR PARTS AND LABOR
WARRANTY. Note: This warranty does not
cover labor costs for the removal and rein-
stallation of the unit. BY PURCHASING
THIS PRODUCT, THE CONSUMER AGREES
AND CONSENTS THAT ALL DISPUTES
BETWEEN THE CONSUMER AND Directed
SHALL BE RESOLVED IN ACCORDANCE
WITH CALIFORNIA LAWS IN SAN DIEGO
COUNTY, CALIFORNIA.

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© 2003 Directed Electronics, Inc
High-powered car audio
systems may produce
sound pressure levels that exceed the
threshold at which hearing loss may
result.
They may also impair a driver’s ability to
hear traffic sounds or emergency vehi-
cles. Use common sense and practice
safe listening habits when listening to or
adjusting your audio system.
WARNING
FEATURES
Super-efficient Class D PWM design.
Runs much cooler than conventional
amp designs.
High-speed MOSFET switching
power supply.
High-current N-channel MOSFET
outputs stable into 2 ohm loads.
Thermal, DC offset, reverse polarity
and short circuit protection.
Continuously variable 12 dB/
octave low-pass crossover.
Switchable 8 dB bass EQ function.
Switchable phase invert function.
Optional remote subwoofer level
control feature.
Buffered RCA output jacks for bi-
amp operation.
Variable input sensitivity optimizes
match with different signal sources.
Gold-plated wire terminals and RCA
connectors ensure maximum signal
transfer.
Rugged one-piece extruded heat
sink finished with injection-molded
mounting feet.

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© 2003 Directed Electronics, Inc
INSTALLATION GUIDELINES
1. Please read this owner’s manual
carefully before installing this ampli-
fier.
2. Disconnect the battery ground
terminal prior to making any elec-
trical connections.
3. Check for any hazards or obstruc-
tions such as gas tanks, fuel or
brake lines, and wiring harnesses
before mounting the amplifier.
4. Pick a mounting location that will
provide adequate access and venti-
lation and protect the amplifier
from heat, moisture, and dirt.
5. Avoid sharp metal areas when
routing cables to the amplifier, and
run RCA cables away from the
power cables and other potentially
noisy car harnesses.
6. The amplifier should be grounded
with a short, heavy gauge wire
connected directly to the car at a
bare metal surface, preferably
scraped body sheet metal. Do not
use factory ground locations, seat
bolts, or brackets that are spot
welded.
7. Always fuse your power connection
within 8 to 10 inches of the battery
terminal. Use a fuse or circuit
breaker rated slightly more than the
on-board fuse(s) of the
amplifier(s). The gauge of power
wire used should take into account
the total current draw of the
system, and the length of wire
used. IASCA and other auto sound
competition organizations have
charts available for this; you can
also find a chart in the MECP study
guide. Minimum wire gauge recom-
mendations for the individual ampli-
fiers are listed on the specification
page. Always use the same gauge
wire for the amplifier ground that
you use for the power wire. Be sure
to examine the battery ground
cable of the vehicle, and if neces-
sary, upgrade it by adding an addi-
tional ground wire that is the same
gauge as the amplifier’s power
wire. Remember, the amplifier can
only deliver its rated output when it
is not current limited by the power
and ground supply wires.
8. This amplifier is designed to drive a
speaker load that measures from 2
to 4 ohms. Keep in mind that heat
is the long-term enemy of automo-
tive electronics and the lower your

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© 2003 Directed Electronics, Inc
speaker load, the more heat is
generated. For low impedance
speaker applications or restricted
ventilation installations, an external
cooling fan may be advisable.
9. Battery and ground connections to
the vehicle should be made with
crimped ring terminals of the appro-
priate size (surface area is what
counts); soldering the terminals
after crimping is also recom-
mended.
10. Due to the high-frequency MOSFET
switching power supply, filtering the
power cable is not generally
required (remember that the amp
can’t deliver full output if the power
supply is restricted). Proper
grounding of the signal source is
mandatory for the amplifier to
reach its performance peak. If the
RCA inputs are not grounded
adequately via the signal source,
electrical noise from the vehicle
may be picked up in the system.

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© 2003 Directed Electronics, Inc
1. RRCCAAOOuuttppuuttJJaacckkss- These pass
through RCA jacks can be used to
send a signal to a second amplifier.
2. RRCCAAIInnppuuttJJaacckkss- Accepts line level
outputs from head units or signal
processors at voltages between
150mV and 8 volts.
3. IInnppuuttGGaaiinnAAddjjuussttmmeenntt- Controls
amplifier sensitivity and is used to
match the input level of the ampli-
fier to the output level of the signal
source.
4. PPhhaasseeSSwwiittcchh- Changes the phase
of the subwoofer speaker output by
180 degrees.
5. CCrroossssoovveerrFFrreeqquueennccyyAAddjjuussttmmeenntt-
Adjusts the crossover point for the
on-board active crossover.
6. BBaassssEEQQSSwwiittcchh- Adds an additional
8 db of boost to the subwoofer
output when on.
7. SSttaattuussLLEEDD- Will light GREEN to
indicate the amplifier is on and
operating normally, and will be off
if the amplifier shuts down due to
short circuit, or DC offset. The LED
will remain on and output will
cease if the amplifier overheats.
8. RReemmootteeSSuubbLLeevveellCCoonnttrrooll- Controls
the subwoofer amplifier gain
controls from a remote location for
ease of adjustment during listening.
WWaarrnniinngg::DO NOT connect a level control knob from other
manufacturers to the Remote Sub Level Control of
any Directed amplifier. Even though the connectors
fit properly, the control knob and connector pin
positions may be different and the amplifier will be
damaged.
FRONT PANEL CONNECTIONS/CONTROLS
OUTPUT INPUT
BASS EQ.PHASE
GAIN FREQ
R
LMIN 30MAX 250
OFF0ON180 POWER
FIGURE 1—AMPLIFIER CONNECTIONS 350d FRONT
7
26
4
38
15

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© 2003 Directed Electronics, Inc
REM GND
SUB OUTPUT
BATT
25A
FUSE
FIGURE 2—AMPLIFIER CONNECTIONS 350d REAR
1 2 4
35
1. SSuubbOOuuttTTeerrmmiinnaallss- Connect the
speakers to these terminals. (Refer
to the Speaker Connection section
of this guide.)
2. PPoowweerrFFuussee--This fuse protects the
amplifier against internal electrical
damage and is meant to protect the
amplifier only. All other power
connections should be fused at the
source.
3. ((++))1122VVoollttPPoowweerr- Connect this
terminal through a FUSE or CIRCUIT
BREAKER to the positive terminal of
the vehicle battery or the positive
terminal of an isolated audio
system battery.
WWAARRNNIINNGG::Always protect this power wire by installing a fuse
or circuit breaker of the appropriate size within
12 inches of the battery terminal connection.
4. RReemmootteeTTuurrnnOOnn- This terminal
turns on the amplifier when (+) 12
volt is applied to it. Connect it to
the remote turn on lead of the head
unit or signal source. If a (+) 12
volt remote turn lead is not avail-
able, a Remote Power Adapter
(P/N #55000) can be used to
supply a remote turn on signal. DO
NOT connect this terminal to
constant (+) 12 volt.
5. GGrroouunndd--Connect this terminal
directly to the sheet metal chassis
of the vehicle, using the shortest
wire necessary to make this
connection. Always use wire of the
same gauge or larger than the (+)
12 volt power wire. The chassis
connection point should be scraped
free of paint and dirt. Use only
quality crimped and/or soldered
connectors at both ends of this
wire. DO NOT connect this terminal
directly to the vehicle battery
ground terminal or any other
factory ground points.
REAR PANEL CONNECTIONS

SPEAKER WIRING DIAGRAMS
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© 2003 Directed Electronics, Inc
Single subwoofer connection (top view)
Two subwoofer connection (top view)
NNOOTTEE::The dual + and -- sub-out terminals of the 350d are paralleled internally and the combined load impedance should be taken
into consideration when connecting multiple subwoofers.

CROSSOVER SETTINGS AND GAIN ADJUSTMENT
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© 2003 Directed Electronics, Inc
Your Directed Audio power amplifier needs to be adjusted carefully to achieve
maximum performance. These are some guidelines to follow when fine-tuning the
amplifier.
Because this amplifier is only designed for subwoofer applications, the low-pass
crossover is active at all times. The crossover point is adjustable to allow more
precise system operation.
Try and keep the setting low enough to prevent image smearing (you should not
be able to hear male voices from the subwoofer) but not so low as to create a gap
between the subwoofer and the mid-bass/midrange speakers. It will be to your
advantage to spend some extra time with this adjustment, listening to familiar
music or system set-up discs to achieve the kind of musical reproduction that you
prefer.
The gain adjustment allows you to set proper signal match for clean, quiet ampli-
fier operation. Start by playing some music you are familiar with. With the gain
adjustment on the amplifier in the middle of its rotation, bring up the volume on
your head unit to the 3/4 volume setting or until you start to hear distortion or
clipping. If you hear distortion before you reach the 3/4 volume setting of your
head unit, reduce the gain setting on the amplifier and start to raise the head unit
volume again. When you can listen to the music at or slightly above 3/4 on your
head unit without audible distortion, slowly raise the gain of the amplifier until
distortion is heard, then back off the gain until the distortion is not audible. This
setting will allow you to reach full output with all but the quietest of source mate-
rial, while avoiding excessive noise in the system.
For systems using the Remote Sub Level Adjustment, increase the subwoofer gain
on the amplifier by 25% and set the Remote Sub Level knob to the center position
after making all system gain and filter adjustments. This will give the Remote Sub
Level Control a wider range of adjustment to the subwoofer output.
You should take into consideration the effect that gain adjustment has on system
frequency response and staging. Again, plan on spending some time with music
that you know getting the gain and crossover settings the way you like. Test discs
and analyzers may help with this process, but in the end it's your ears that count
--listen to the music!

SPECIFICATIONS
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© 2003 Directed Electronics, Inc
RMS continuous power driven into 4 ohms
from 20 to 250 Hz with less than 0.4% Total
Harmonic Distortion @ 14.4 VDC
RMS continuous power driven into 2 ohms
from 20 to 250Hz with less than 0.6% Total
Harmonic Distortion @ 14.4 VDC
Dynamic power rating (IHF-202 Standard) at
minimum load
150 watts
350 watts
250 watts
Directed model 350d
Signal-to-Noise Ratio Greater than 80 dB
Frequency Response 20-200 Hz +0, -1 dB
Damping Factor 50 (typical)
Crossover Low-pass 12 dB/ octave
variable from 30 to 250 Hz
Bass Equalization +8 dB, centered at 40Hz
Input Impedance 20K ohms
Input Sensitivity Variable from 150 mV to 8 volt
Output Impedance 2 to 4 ohms
Supply Voltage 10 to 16 VDC
Fusing and Power 25A
Minimum Cable Requirements (AWG) #12
(Per amp, trunk mounted)

The company behind this system is Directed Electronics, Inc.
Since its inception, Directed has had one purpose, to provide customers with the
finest vehicle security, car stereo products, rear seat entertainment, and accessories
available. The recipient of more than 20 patents in the field of advanced electronic
technology, Directed is ISO 9001 registered.
Directed® is committed to delivering world-class quality
products and services that excite and delight our customers.
Directed Electronics, Inc.
Vista, California 92081
www.directed.com
Directed is a proud member of
Quality Directed products are sold and serviced throughout North America and around the world
Call 800 274 0200 for more information about our products and services
© 2003 Directed Electronics, Inc. - All rights reserved - G45011 11/03