Rockford Fosgate PUNCH 501XP, Installation & Operation Manual

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

stereo and 4

Ω

bridged.

10

O

PERATION

I

NSTALLATION

80

4.1mH 1000µF

8.2mH

500µF

16mH

250µF

100

3.1mH

800µF

6.2mH

400µF

12mH

200µF

130

2.4mH

600µF

4.7mH

300µF

10mH

150µF

200

1.6mH

400µF

3.3mH

200µF

6.8mH

100µF

260

1.2mH

300µF

2.4mH

150µF

4.7mH

75µF

400

.8mH

200µF

1.6mH

100µF

3.3mH

50µF

600

.5mH

136µF

1.0mH

68µF

2.0mH

33µF

800

.41mH

100µF

.82mH

50µF

1.6mH

26µF

1000

.31mH

78µF

.62mH

39µF

1.2mH

20µF

1200

.25mH

66µF

.51mH

33µF

1.0mH

16µF

1800

.16mH

44µF

.33mH

22µF

.68mH

10µF

4000

.08mH

20µF

.16mH

10µF

.33mH

5µF

6000

51mH

14µF

.10mH

6.8µF

.20mH

3.3µF

9000

34mH

9.5µF

68mH

4.7µF

.15mH

2.2µF

12000

25mH

6.6µF

51mH

3.3µF 100mH

1.6µF

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.

!

ADJUSTING GAIN

Do the following individually for each channel.

To adjust the gain setting, turn the amplifier gains all the way down. Turn the source unit volume up
until distortion is audible and then turn it down a bit until the distortion is inaudible. This will be
about two thirds all the way up on most source units. Next, turn the amplifier gain setting until once
again distortion is audible and then back it down until the distortion is inaudible. Rockford Fosgate
source units do not distort, so the volume can be used at maximum setting.

NOTE

: For a more in depth setting procedure, contact Rockford Technical Support.