14
Initial start-up and functions
1
Power & Protect LEDs
The
Power & Protect LEDs
indicate the operating
mode of the active subwoofer. If the
Power LED
lights green, the active subwoofer is switched on
and ready for operation.
If the
Protect LED
lights up red a malfunction has
occurred. A malfunction may have different causes
as the HELIX U 8A / U 10A is equipped with different
protection circuits. These protections shut off the
active subwoofer in case of overheating, over- and
undervoltage and false connection. Please check
for connecting failures such as short-circuits, wrong
connections, wrong adjustments and over temper-
ature. If the active subwoofer does not turn on it is
defective and has to be send to your local author-
ized dealer for repair service. A detailed description
of the malfunction and the purchase receipt has to
be attached.
2
Phase
This switch is used to toggle the phase between 0°
and 180°. This allows to match the phase of the ac-
tive subwoofer with the other speakers thus avoid-
ing any cancellations in the frequency response due
to phase shifts. If the changeover does not lead to
the desired result, a fine tuning can be done with
control 5 (
Phase Shift
).
3
Auto Remote
The U 8A / U 10A will be turned on automatically if
the
Highlevel Input
is used or if a signal is applied to
the remote input (REM) terminal of the
Power Input
.
The
Auto Remote
switch allows to activate / deacti-
vate the automatic turn-on feature of the
Highlevel
Input
. The feature should be deactivated (Auto Re-
mote = Off) if there are e.g. disturbing noises while
switching on /off the active subwoofer.
Note:
If the automatic turn-on function is deactivat-
ed it is mandatory to use the remote input to power
up the active subwoofer! The highlevel signal will be
ignored in this case.
4
Lowpass
This control is used to adjust the crossover frequen-
cy of the lowpass filter from 50 Hz to 150 Hz. As
a reasonable initial value for adapting the active
subwoofer to the other loudspeaker systems, we
recommend a setting of 100 Hz (center position of
the control).
5
Phase Shift
This control is used to fine tune the phase from 0° to
180° if the phase adjustment with the
Phase
switch
(see item 2) did not lead to the desired result.
Note:
Always use the
Phase
switch first to adjust
the phase.
6
Input Level
This control is used to adapt the input sensitivity to
the output voltage of the connected signal source.
The control range of the RCA /
Line Input
(lowlevel)
is 0.3 - 4 Volts and 1.2 - 20 Volts for the
Highlevel
Input
.
7
Remote Control
This input is used to connect the included cable re-
mote control. The remote control allows you to con-
trol the volume of the active subwoofer.
8
Highlevel Input
2-channel highlevel loudspeaker input to connect
the active subwoofer directly to the loudspeaker
outputs of OEM / aftermarket radios that do not
have any lowlevel line outputs.
If this input is used the remote input (REM) of the
Power Input
does not need to be connected as the
active subwoofer will automatically turn on once a
loudspeaker signal is applied.
Attention:
Solely use the connection cable with the
6-pole connector and flying leads which is included
in delivery!
