14
Initial start-up and functions
320 Hz the highpass should be adjusted to 80 Hz
or less (one octave = doubled frequency or halved
frequency).
If a subwoofer is connected we recommend to use
the highpass control (7) as variable low-frequency
highpass filter or turn it counterclockwise to 15 Hz
to get a subsonic filter.
7
HPF
This control is used to adjust the crossover frequency
of the highpass filter from 15 Hz bis 4,000 Hz. This
control is activated if the
X-Over
switch of the spe-
cific channel pair is set to HPF (highpass filter). On
channel pair C/D it is also activated in LPF / Band-
pass and its adjustment is mandatory.
8
Line Input
4-channel pre-amplifier input to connect signal
sourc es such as head units / radios / DSPs.
Important:
It is strictly forbidden to use the
High-
level Input
and pre-amplifier inputs (
Line Input
) at
the same time. This may cause severe damage
to the pre-amplifier outputs of your head unit / car
radio.
9
Input Level
These controls are used to adapt the input sensitiv-
ity of the channel pairs A/B resp. C/D to the output
voltage of the connected signal source.
This is not a volume control, it´s only for adjusting
the amplifier gain. The control range of the RCA /
Line Input
is 1 - 6 Volts and 2.5 - 14 Volts for the
Highlevel Input
.
If the
Highlevel Input
is used with a standard car
radio we recommend an input sensitivity of roughly
9 Volts - turn the control from min position to 1/3
position - 11 o’clock position.
10
Highlevel Input
4-channel highlevel loudspeaker input to connect
the amplifier directly to the loudspeaker outputs
of OEM / aftermarket radios that do not have any
pre-amplifier outputs.
The
Highlevel Input
is equipped with our proprietary
ADEP circuit (Advanced Diagnostics Error Protec-
tion) which ensures that the car radio detects the
amplifier as a speaker and thus neither any function
of the radio (e.g. fader) will be deactivated nor any
error log in the CPU of the car will be created.
If this input is used the remote input (
REM
) does
not need to be connected as the amplifier will
automatically turn on once a loudspeaker signal is
applied.
Attention:
Solely use the pluggable screw-terminal
for the highlevel connector which is included in de-
livery or an optional available cable harness from
the HELIX accessory assortment!
Important:
It is strictly forbidden to use the
High-
level Input
and pre-amplifier inputs (
Line Input
) at
the same time. This may cause severe damage to
the pre-amplifier outputs of your car radio.
11
GND
The ground cable should be connected to a com-
mon ground reference point (this is located where
the negative terminal of the battery is grounded
to the metal body of the vehicle) or to a prepared
metal location on the vehicle chassis i.e. an area
which has been cleaned of all paint residues. Rec-
ommended cross section: min. 16 mm² / AWG 6.
12
REM
The remote lead should be connected to the remote
output / automatic antenna (aerial positive) output
of the head unit / car radio. This is only activated
if the head unit is switched on. Thus the amplifier
is switched on and off together with the head unit.
This input needn’t to be assigned if the
Highlevel
Input
is used.
13
+12 V
Connect the +12 V power cable to the positive ter-
minal of the battery. Recommended cross section:
min. 16 mm² / AWG 6.
14
Fuse
The input fuses are connected in parallel and pro-
vide protection against an internal fault of the de-
vice, therefore the system must be additionally pro-
