Rockford Fosgate punch 250M - Manual (Page 7)

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.
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.
!
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
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.
!