– 8 –
– 9 –
WIRING DIAGRAM
DANGER:
Use the specified amperage fuse only.
Higher amperage may cause serious damage or even a fire.
ADJUSTMENTS
Turn-on your head-unit keeping your volume at the lowest setting. The POWER status LED
of the ATB120QBA amp-module should light up now. If not, turn-off your head-unit and re-
check all wiring to and from the amplifier for missing or faulty connections.
PROTECTION INDICATOR
This active subwoofer is equipped with an overload protection. In case of internal short
circuit or increased temperature, the overload protection is activated, and the PROTECT
LED indicator comes on. Through this the amplifier is protected against damage. In case of
the thermal protection a certain cooling time must be allowed after which the amp-module
will resume operation.
LOWPASS CROSSOVER FREQUENCY ADJUSTMENT
The lowpass cut-off frequency setting, marked as „LOW PASS“ on the active subwoofer,
depends on the dimension of the vehicle and the mounting location. As a rule of thumb,
settings in a range between 70 to 90 Hz will render best sonic results. For an intermediate
lowpass crossover setting to attempt input gain and phase-shift control adjustments, go for a
VR-pot set to approx. 80 Hz – and after input gain has been adjusted, it is advisable to fine
tune the lowpass crossover frequency for best possible sound quality.
Note:
In general, setting the lowpass crossover frequency too low, will result in a weak
and muddy sounding bass, while setting this crossover frequency too high will result in a
‘booming’ bass sound and reduced low end extension.
INPUT GAIN
The input level control allows the ATB120QBA to be matched to almost any car, to work well
within a wide range of output levels. The following procedure can be applied: Turn on the
head unit and adjust the volume level to an elevated but still sane output. Now increase the
GAIN potentiometer by turning it clockwise (on the ATB120QBA amp panel) until the bass
content is perceived as sufficient and balanced.
BASS BOOST
The bass boost has to be played by ear. With the controller set to “0 dB”, the bass boost
is deactivated, with position “12 dB”, the frequencies around 45 Hz are boosted at most
– which will improve the low-end extension in smaller compact type cars. Note that with
bass boost enabled, the subwoofer will have less max. dB headroom since the very low
frequencies are amplified with a higher gain and thus, woofer and amp module reach their
respective limits earlier.
MAIN
FUSE
Car battery
12 VDC
Headunit
Ground
REM ON/OFF
i.e. Amp remote
q
q
Lowpass
Phase Shift
Bass-Boost 0 – 12 dB
Gain
Fuse (10A)
+12V Power Terminal
REM (Amp Remote) Terminal
GND Power Terminal
High Level Input – (to use just cut the RCA cable)
RCA Input
INPUT
REMOTE
CONTROL
PROTECT
POWER
FUSE
10 A
PHASE
SHIFT
LOW PASS
BASS BOOST
GAIN
0°
180°
0 dB
12 dB
MIN.
MAX.
50 Hz
150 Hz
ATB120QBA
REM OUT
REM IN
GND
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Power/Protect Status LED
Bass Level Remote Control
