Zapco Studio X Series - Manual (Page 6)

The ST-4X
Four channel, compact chassis car amplifier with RCA pre-amp input and
speaker level input
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1. Rear Crossover selector determines high pass, low pass, or full range
for the rear channels
2. Bass Boost allows 6dB or 12dB boost of bass frequencies in the rear
channels
3. Rear Gain: This control balances output of the head unit to the input of
the amp and with the front amp channels
4. Rear RCA IN connectors are to connect the ST-4X to an aftermarket
head unit rear outputs
5. Front RCA IN connectors are to connect the ST-4X to an aftermarket
head unit front outputs
6. Front Crossover selector determines high pass or full range for the front
outputs
7. HPF If you use High Pass crossover, this control determines frequency
80Hz to 3Khz
8. Speaker Level input. The ST-4X has Hi-level input plugs for front and
rear speaker level inputs. *See Install notes of ST-2X
ST-4X Input
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