Gain Controls; Bass Boost Control; High-Pass/Low-Pass Filter Controls; Frequency (Hz) Controls - Audiopipe APMR-1504 Owner's Manual

English
The Input Connections are platinum-plated RCA Jacks and are labeled as FRONT RIGHT,
FRONT LEFT, REAR RIGHT and REAR LEFT. The Gain Controls provide a wide adjustment
range to accommodate output levels from any brand of source unit.

Gain Controls

Separate Front and Rear Gain Controls allow you to set the nominal operating level of the
marine amplifier. The marine amplifier's range, 250mV to 2.5V for RCA inputs or 500mV
to 5V for speaker level inputs, can accommodate input levels from virtually any brand of
source unit.

Bass Boost Control

The marine amplifier also features a "high-Q" (i.e. narrow frequency band) Bass Boost
circuit.
It acts much like an equalizer, with adjustable gain (from 0 to ~18dB) fixed at 45Hz. Use
this feature to tune low-frequency audio response to compensate for a less than ideal
subwoofer enclosure design. The added boost produces rich, full bass tones that are
normally difficult to reproduce in the car audio environment.
NOTE: If Bass Boost is undesired, set Bass Boost to 0dB.

High-pass/Low-pass Filter Controls

Frequency (Hz) Controls

The front crossover frequency is fully adjustable between 55Hz and 550Hz. The rear
crossover frequency is fully adjustable between 55Hz and 5500Hz (via the Rear Crossover
Frequency Multiplier) for a wider range of crossover points. Use this feature, along with
your speaker manufacturer's recommended crossover frequencies, to quickly design a
more advanced system (see Applications on page 6). NOTE: If either of the X-Over Mode
Switches is set to OFF, varying the Freq (Hz) Control will produce no effect.
Rear X-Over Frequency Multiplier Switch
When engaged, this switch increases the crossover frequency of the rear channels by a
factor of 10. Example: If the Freq (Hz) dial is set for 240Hz, pushing in the Multiplier Switch
changes the setting to 2400Hz.
X-Over Mode Switches
These switches are equipped with 12dB per octave electronic filters for precise frequency
attenuation with minimal phase distortion. The steep crossover slopes keep midrange
tones out of the sub-woofer and thereby eliminating an unnatural "nasal" tone quality in
the audio system. Each filter is activated by sliding the X-Over Mode Switch to either LP
or HP.
Input Mode Switches
These switches allow you to set the input mode for front and rear channels. Stereo input
allows full left and right stereo operation. Right (bridged) input allows a single channel
input for bridged operation. This is especially useful in high powered systems when using
the APMR-1504 as a bridged 2-channel marine amplifier. L ~ R (sum mono) allows a
stereo input to be summed into a mono output.
Rear Channel Input Select
This switch allows you to use a 2 channel input to drive all 4 channels of this marine
amplifier.
Speaker Level Inputs
These provide connections for a high-level stereo source. In addition, these connections
are provided for installations when the source unit's RCA outputs are unavailable.
WARNING: When using the speaker (high-level) inputs, the Black wire must be grounded
at the Radio. Failure to do this will result in noise and improper operation.
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