HELIX DSP PRO Manual page 18

Installation
Connection of HELIX DSP PRO to the head unit
(radio):
Caution: Carrying out the following steps will re-
quire special tools and technical knowledge. In or-
der to avoid connection mistakes and / or damage,
ask your dealer for assistance if you have any ques-
tions and follow all instructions in this manual (see
page 13).
It is recommended that this unit will be installed by
an authorized HELIX dealer.
1. Connecting the pre-amplifier inputs
Use the correct cable (RCA / cinch cable) to con-
nect these inputs to the pre-amplifier / lowlev el /
cinch outputs of your car radio.
Each input can be assigned to any output using
the DSP PC-Tool software. The automatic turn-
on circuit does not work when using the pre-
amplifier inputs. In this case the „Remote Input"
has to be connected to activate the HELIX DSP
PRO.
Important: It is strictly forbidden to use the
highlevel input and pre-amplifier inputs at the
same time. This may cause severe damage to
the pre-amplifier outputs of your car radio.
2. Connecting the highlevel speaker inputs
The highlevel loudspeaker inputs can be con-
nected directly to the loudspeaker outputs of
an OEM or aftermarket radio using appropriate
cables (loudspeaker cables with 1mm² / AWG18
max.). It is not mandatory to use all speaker in-
puts.
Make sure that the polarity is correct. If one or
more connections have reversed polarity this
may affect the performance of the processor. If
this input is used the remote input has not to be
used as the processor will automatically turn on
once a loudspeaker signal is received.
3. Adjustment of the input sensitivity
If you want to change the input sensitivity you
have to open the device at first. Remove the
four Philipps head screws of the side pan el (in-
put side) and pull out the bottom plate. Now you
have access to the eight trim potentiometers
that allow adjusting each channel individually.
The assignment of the trim pots to the respec-
18
tive channels is shown in the figure 1 on page
17.
Please note: The settings of the trim potentio-
meters affects both the lowlevel inputs and the
highlevel inputs!
The sensitivity range of the highlevel inputs can
be modified by inserting the jumper into the op-
posite position (see figure 2 / page 17).
The sensitivity range of the two lowlevel inputs
G and H can be changed by inserting the other
jumper into the opposite position (see figure 3 /
page 17). Thus it is possible to connect even
mobile devices with significantly lower output
voltage (like smartphones) to the HELIX DSP
PRO.
Follow the subsequent steps if you like to per-
fectly adapt the processors input sensitivity to
your audio source by using the internal trim po-
tentiometers:
1. Don't connect any amplifier to the outputs of
the processor during this setup.
2. Adjust the volume of your radio to approx.
90 % of the max. volume and playback a
1 kHz full scale test tone (0 dB) via CD
drive.
3. The adjustment will be easier when you
connect and adjust one input channel after
the other.
4. If the Clipping LED already lights up, you
have to reduce the input sensitivity via the
respective trim potentiometer until the LED
goes out.
If the pot is already set to right stop position
then it will be necessary to change the sen-
sitivity range by repositioning the jumper
(see figure 2 / page 17). Note that this will
only have an effect on the highlevel inputs!
5. Increase the input sensitivity by turning the
respective pot counterclockwise until the
LED lights up. Now turn the potentiometer
clockwise until the Clipping LED goes out
again.
6. Repeat this process for each channel you
are using.
4. Connecting a digital signal source
If you have a signal source with optical or coa-
xial digital output you can connect it to the pro-
cessor using the appropriate input.