Using Passive Crossovers - Rockford Fosgate Mono Amplifier Installation & Operation Manual

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 2Ω.
!

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 2Ω.
OR
(R+) Gray
(R–) Gray/Black
(L+) White
(L–) White/Black
Freq.
Hertz
12000
High
Level
Input
L
6dB/Octave Low-Pass
Speaker Impedance
2 OHMS
L C
80 4.1mH 1000mF
100 3.1mH 800mF
130 2.4mH 600mF
200 1.6mH 400mF
260 1.2mH 300mF
400 .8mH 200mF
600 .5mH 136mF
800 .41mH 100mF
1000 .31mH 78mF
1200 .25mH 66mF
1800 .16mH 44mF
4000 .08mH 20mF
6000 51mH 14mF
9000 34mH 9.5mF
25mH 6.6mF
L = Low-Pass (Inductor)
C = High-Pass (Capacitor)
For more information, see your Authorized Rockford
Fosgate Dealer.
I
NSTALLATION
C
6dB/Octave High-Pass
4 OHMS
L C L
8.2mH 500mF 16mH
6.2mH 400mF 12mH
4.7mH 300mF 10mH
3.3mH 200mF 6.8mH
2.4mH 150mF 4.7mH
1.6mH 100mF 3.3mH
1.0mH 68mF 2.0mH
.82mH 50mF 1.6mH
.62mH 39mF 1.2mH
.51mH 33mF 1.0mH
.33mH 22mF .68mH
.16mH 10mF .33mH
.10mH 6.8mF .20mH
68mH 4.7mF .15mH
51mH 3.3mF 100mH
8 OHMS
C
250mF
200mF
150mF
100mF
75mF
50mF
33mF
26mF
20mF
16mF
10mF
5mF
3.3mF
2.2mF
1.6mF
7