Using passive crossovers, Wiring, Lc c c – Rockford Fosgate Mono Amplifier User Manual
Page 7: Speaker impedance

80
4.1mH 1000mF
8.2mH
500mF
16mH
250mF
100
3.1mH
800mF
6.2mH
400mF
12mH
200mF
130
2.4mH
600mF
4.7mH
300mF
10mH
150mF
200
1.6mH
400mF
3.3mH
200mF
6.8mH
100mF
260
1.2mH
300mF
2.4mH
150mF
4.7mH
75mF
400
.8mH
200mF
1.6mH
100mF
3.3mH
50mF
600
.5mH
136mF
1.0mH
68mF
2.0mH
33mF
800
.41mH
100mF
.82mH
50mF
1.6mH
26mF
1000
.31mH
78mF
.62mH
39mF
1.2mH
20mF
1200
.25mH
66mF
.51mH
33mF
1.0mH
16mF
1800
.16mH
44mF
.33mH
22mF
.68mH
10mF
4000
.08mH
20mF
.16mH
10mF
.33mH
5mF
6000
51mH
14mF
.10mH
6.8mF
.20mH
3.3mF
9000
34mH
9.5mF
68mH
4.7mF
.15mH
2.2mF
12000
25mH
6.6mF
51mH
3.3mF 100mH
1.6mF
7
I
NSTALLATION
10. Perform a final check of the completed system wiring to ensure that all connections are
accurate. Check all power and ground connections for frayed wires and loose connections
which could cause problems.
NOTE: Follow the diagrams for proper signal polarity.
CAUTION: These amplifiers are not recommended for impedance loads below 2
Ω.
High
Level
Input
OR
(L+) White
(L–) White/Black
(R+) Gray
(R–) Gray/Black
USING PASSIVE CROSSOVERS
A passive crossover is a circuit that uses
capacitors and/or coils and is placed on
speaker leads between the amplifier
and speaker. The crossover delegates a
specific range of frequencies to the
speaker for optimum driver
performance. A crossover network can
perform one of three functions: High-
Pass (capacitors), Low-Pass (inductors
or coils) and Bandpass (combination of
capacitor and coil).
The most commonly used passive
crossover networks are 6dB/octave
systems. These are easy to construct
and require one component per filter.
Placing this filter in series with the
circuit will reduce power to the speaker
by 6dB/octave above or below the
crossover point depending on whether
it is a high-pass or low-pass filter. More
complex systems such as 12dB/octave
or 18dB/octave can cause impedance
problems if not professionally designed.
Passive crossovers are directly
dependent upon the speaker's
impedance and component value for
accuracy. When passive crossover
components are used in multiple
speaker systems, the crossover's effect
on the overall impedance should be
taken into consideration along with the
speaker's impedance when determining
amplifier loads.
CAUTION: These amplifiers
are not
recommended for
impedance loads
below 2
Ω.
Freq.
Hertz
Speaker Impedance
2 OHMS
8 OHMS
4 OHMS
L
L
L
C
C
C
6dB/Octave Low-Pass
6dB/Octave High-Pass
L
C
L = Low-Pass (Inductor)
C = High-Pass (Capacitor)
For more information, see your Authorized Rockford
Fosgate Dealer.
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