Rockford Fosgate 250 - Manual (Page 15)

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U
SING
P
ASSIVE
C
ROSSOVERS
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 (capaci-
tors), 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: The Punch ampli-
fiers are not recommended for impedance loads below 2
Ω
stereo and 4
Ω
bridged (mono) loads.
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