I Subwoofers and the PN90 Crossover Network
Adding subwoofers to speaker systems like the one shown in the diagram can provide extended frequency range and
superior overall sound quality. After dividing the line-level audio from the preamplifier or mixing console into sepa-
rate frequency bands via the PN90 crossover network, the separate frequency bands are sent to separate power ampli-
fiers.
TWO-CHANNEL
MIXING
GRAPHIC
CONSOLE
EQUALIZER
L
R
Precautions for operating the PN90
• Do not connect the PN90 between the power amplifier and speakers. The high voltage levels produced can damage
the PN90.
• Use the PN90 with a load impedance of between 7.5k
• The polarity of the LOW signal is inverted at the crossover point between the LOW and HIGH signals. Compen-
sate for this by reversing the polarity when connecting the power amplifier output jacks to a subwoofer. Note that
you must reverse the polarity between the power amplifier and subwoofers rather than between the PN90 and
power amplifier to prevent damage to the connected device.
• The PN90's connectors are unbalanced phone jacks. Use shielded audio cable with phone plugs to connect to the
PN90. Do not use speaker cable.
• Adjust the level of the LOW and HIGH signals using the power amplifier volume controls.
PN90
LEFT
HIGH
RIGHT
L
LEFT
TO POWER
INPUTS
AMP INPUTS
RIGHT
R
LEFT
LOW
RIGHT
TWO-CHANNEL
POWER AMPLIFIER
L
L
INPUT
OUTPUT
R
R
L
L
INPUT
OUTPUT
R
R
TWO-CHANNEL
POWER AMPLIFIER
Ω
Ω
and 30k
. (Rated load impedance is 15k
SPEAKER
SYSTEM
SUBWOOFER
SPEAKER
SYSTEM
SUBWOOFER
Ω
)
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