Rainbow 271052 Installation Manual - page 32
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Subwoofer Adjustment
iPaul DM2000
Finding the correct adjustment of the volume, separation frequency and the phase position, requires a good deal of
time, patience, and experience as well as a well-known title from your favorite CD. The first step should be
specifying the location for assembly of the subwoofers. Preference to the trunk corners and/or partition near the
trunk floor only insignificantly increases the radiation resistance. Thus the expected increase of efficiency and
improvement of dynamics to around the optimal 3 dB are not fully attainable.
The adjustment of the cut-off frequency, phase position and the volume controls is applicable only for the fixed
installation location. All adjustments should be optimized by the user only while the front and rear systems are in
operation. Operation of the subwoofers exclusively without the front and/or rear system is not meaningful and leads
to the incorrect tuning of level controls, separation frequency, and phase position.
Adjustment of the cut-off Frequency:
The cut-off frequency of the subwoofers must correspond to the cut-off frequency of the front and rear systems. If
the front and/or rear system receives a high-pass signal of 80 Hz, the cut-off frequency of the subwoofers should be
adapted accordingly. The cut-off frequency should not, however, be significantly higher. At a maximum of 80 Hz
- 100 Hz it is impossible to detect the subwoofers and a clean roll-off of 80 Hz -3 dB is given in both cut-off
frequencies, thereby making it optimal.
Adjustment of the Phase Position:
The relative phase position between the subwoofer and the front and/or rear system is to a large extent independent
of the cut-off frequency of the subwoofer. It is recommended as the second step that the correct and/or optimal
phase position from the subwoofer to the front and/or rear system be found. This is a result of the correct
adjustment and correct polarity from the additional sound from the subwoofer and the front and/or rear system and
recognizable by a drier and more voluminous bass. In the event of incorrect polarity of the subwoofers or the front
and/or rear systems a detraction of sound occurs, which is recognizable by a weak and matte bass. The amplifier
iPaul DM2000 possesses a 0° - 180° phase shifter, with which the phase of the subwoofers can be adapted to agree
with the front system.
Adjustment of the Volume Controllers:
As the last step the volume level controller of the subwoofers should be adjusted to the front and/or rear system.
Adjust level controller of the front and/or rear system in such a way that, together with the fader of the car radio, an
optimal volume is ensured. Set front and/or rear system to a middle volume level with a familiar music title from a
favorite CD. Set subwoofer volume at the level controller of the amplifier to a quiet level or to the minimum (not
on radio). Afterwards adjust level controller of the subwoofer slowly during constant music and increase the
volume of the subwoofers until the subwoofer stands out clearly from the overall sound. Afterwards, reduce the
subwoofer volume with the level controller until the subwoofer no longer is emphasized in the overall sound. Do
not further adjust level controller of the subwoofers.
TIP:
Insert the included remote control for „GAIN“ and „PHASE“ in the „REMOTE“ (4) socket and,
from the driver’s seat, adjust „GAIN“ and „PHASE“ until the bass rendition is optimal.