Rockford Fosgate RFA-410 - Manual (Page 6)

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U
SING
T
HE
P
UNCH
A
UDIOPHILE
W
OOFERS
Speakers are built in different sizes to optimize their performance in
different frequency bands. Crossovers are used to route the different
frequency bands for each appropriate speaker. There are two opera-
tional types of crossovers, active and passive. An active crossover is
an electronic filter which is placed before the amplifier and separates
the signal fed to different amplifiers in the system. A passive crossover
is positioned after the amplifier and separates the signal fed to each
speaker in the system. Active crossovers offer the accuracy and
flexibility needed for a sophisticated system and are used in complex
multiple amp designs. Passive crossovers (capacitors and inductors)
allow the use of multiple speakers in a simple system which can easily
be expanded over time. We recommend using a 6dB per octave,
100Hz low pass crossover for the Punch Audiophile Woofers when
used with a passive system.
To customize the installation, try adjusting the crossover point one
octave up or down to optimize the system staging.
The Punch Audiophile Woofers are used for the sub-bass region,
those frequencies below 100Hz. This is the foundation for the music
and the frequency range you feel. Before selecting the passive
crossover it is necessary to calculate the load impedance of the
speaker system. In a series circuit the impedance is determined by
the formula:
R
T
= R
1
+ R
2
+ R
3
+ etc.
In a parallel circuit the impedance is determined by the formula:
Where R
T
is the total speaker load and R
1
, R
2
, etc. represent each
speaker in the system.
The crossover is connected in line to the positive terminal of the
speaker system. Crossovers are available from Authorized Rockford
Fosgate Dealers.
1 1 1 1 1
= + + + + etc.
R
T
R
1
R
2
R
3
R
4
C
A L C U L A T I N G
L
O A D
I
M P E D A N C E