Rockford Fosgate AF/4HD Installation Manual
INSTALLATION MANUAL
AF/4HD ACTIVE FILTER ADJUSTABLE CROSSOVER
PRACTICE SAFE
CONTINUOUS EXPOSURE TO SOUND PRESSURE LEVELS OVER 100dB MAY CAUSE
PERMANENT HEARING LOSS. HIGH-POWERED AUTOSOUND SYSTEMS MAY PRODUCE
SOUND PRESSURE LEVELS WELL OVER 130dB. USE COMMON SENSE AND PRACTICE
SAFE SOUND.
SOUND™
Make your
from
man about Perfect Power alternators power cables, speaker wire
cosmetic
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ibdbdb%?db@ a division of
accessories
and
system complete
fabric.
Rockford
with
installation
Corporation. Ask your
accessories
sales-
connectors
.
TABLE OF CONTENTS
Introduction.. .......................................................................................................................................................
Input and Output Levels .....................................................................................................................................
Power Wiring Instructions ...................................................................................................................................
Fuse Protection ..................................................................................................................................................
Figure 1 Illustration View....................................................................................................................................
Frequency Selection
Band Selection ...................................................................................................................................................
Figure 2 Illustration View
Switching Examples ..........................................................................................................................................
Summing Channel ..............................................................................................................................................
Phase Shift and Cancellation .............................................................................................................................
Extra Features ....................................................................................................................................................
Active vs. Passive Crossovers
Specifications
Warranty Information ..........................................................................................................................................
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1
1
1
1
2
2
4
6
7
9
9
11
11
14
15
INTRODUCTION
The
Design) to provide state-of-the-art flexibility, performance and pleasing aesthetics. Its features
include: four stereo inputs with true fading capability, infinitely adjustable frequency modules,
four user definable high pass, low pass and band pass filters, single channel summing for mono
applications, fully isolated high voltage power supply, low noise circuitry, low distortion, high
load driving capacity 750 mV RMS input level, 750 mV RMS output level.
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Rockford Fosgate AF/4HD is an active electronic crossover that incorporates HD (Hybrid
FADING CAPABILITY
ONE CHANNEL CAN BE SUMMED FOR MONO APPLICATIONS
TWO USER SELECTABLE FILTERS (HIGH PASS OR LOW PASS)
TWO USER ADJUSTABLE BAND PASS FILTERS THAT CAN ALSO
BE SELECTED AS HIGH OR LOW PASS FILTERS
CAPABLE OF UTILIZING ONE TO FOUR INPUTS
GOLD PLATED RCA’S
INTERNAL FUSE FOR PROTECTION
CONCEALED MOUNTING
AUDIO CIRCUIT IS HYBRID DESIGNED
LOW DISTORTION
WIDE RANGE OF FREQUENCY MODULES, OR FASHION YOUR OWN
SMALL, LOW COST
.
HIGH LOAD DRIVING CAPACITY: CAPABLE OF HANDLING UP TO 10
ROCKFORD FOSGATE AMPLIFIERS
.
12dB/OCTAVE CROSSOVER SLOPES
.
CASCADING OF OUTPUT TO INPUT PROVIDES 24dB/OCTAVE SLOPE
INPUT AND OUTPUT LEVELS
The AF4 is designed for preamp-level (750 mVRMS) levels. Speaker-level inputs must be
attenuated to under 1.0 VRMS.
Net gain in the filter passband of the AF4 is unity. (output levels are equal to input levels)
POWER WIRING INSTRUCTIONS
The Black 16-gauge wire should be grounded to the chassis. The White (or white with a red
stripe) 16-gauge wire should be connected to a source of constant 12-Volt power. The Red
gauge wire is the remote turn-on wire. Connect it to the radio “Auto-Antenna” lead, or to some
other point that goes “positive” when the system turns on. See Figure 1.
PROTECTION FUSE
The AF4 has a built-in main power fuse for over current protection. If blown, replace with AGC
1/2
amp fast blow fuse. See Figure 1 for fuse location.
16-
1
AF/4HD WIRING/FUSE/MODULE AND JUMPER LOCATIONS
Inputs
Modules For Band
Switches For Number
Of Inputs And A
Summing Channel
7
Fuse
1/2
Amp
Fast Blow
And Frequency/
-
outputs
Circuit Hybrids
FREQUENCY SELECTION
Custom crossover frequency modules will allow you to create notch filters oroverlapfrequencies
to “equalize” in or out a desired response.
High and Low crossoverfrequencies in the AF4 are selected by inserting frequency modules in
sockets in the internal PC board.
In order to change a frequency module, remove the four machine screws that hold the cover and
remove the cover. Remove the frequency module you wish to change, and insert the new
module in its place.
L
Power LED
FIGURE 1
L
Mounting Holes
&
Locations
See Fig. 2 for module locations.
WARNING! TURN OFF SYSTEM BEFORE REMOVING MODULES!
2
BUILDING A CUSTOM CROSSOVER MODULE
,
If you want a frequency not available in the standard
half-octave intervals from 50 Hertz to 9,000 Hertz), you can, in fact, build your own module.
You will need:
1. An 8-pin DIP component carrier
2. Soldering equipment
I
3. A source of
Determine the resistance value you need for the frequency you want from the formula below.
R=
1 .38 (10
“f"
is the frequency that you want.
1/4-watt
1
-
7
)f
or
OHM’s
FREQUENCY RESISTOR VALUES
The following table was tabulated by using the formula that was given earlier.
Frequency Resistance
50 Hz
70
Hz
100 Hz
150 Hz
200
Hz
275
Hz
400
Hz
550 Hz
750
Hz
150k
Ohms
OOk
Ohms
1
75k Ohms
47k Ohms
36k Ohms
27k Ohms
18k Ohms
13k Ohms
9.7k
Ohms
Rockford
1/8
watt resistors. (Preferably 1% resistors)
modules (which are available at
Frequency Resistance
80 Hz
1k
Hz
1.5k
Hz
2k Hz
3k Hz
4.5k Hz
6.5k Hz
9k Hz
13k Hz
9.1 k Ohms
7.5k
Ohms
4.7k
Ohms
3.6k
Ohms
2.4k
Ohms
1.6k Ohms
1.1k Ohms
820
Ohms
557
Ohms
3
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