Subwoofer connection
The GTA 270 DSP features three diff erent options of con-
necting a subwoofer:
– An active subwoofer or an additional amplifi er are con-
nected with a cinch (RCA) cable to the two SUBWOOFER
OUTPUT sockets (see Fig. 7). The setting options of the
integrated DSP (Digital Sound Processor) can be used
in this case.
– A passive subwoofer is connected to the bridged loud-
speaker output (see the section "Bridged loudspeaker
connections"). To be able to use the setting options of the
integrated DSP (Digital Sound Processor), the two INPUT
sockets must additionally be connected with a commer-
cially available cinch (RCA) cable with the two SUBWOOFER
OUTPUT sockets (see Fig. 8).
– A passive subwoofer is connected to the bridged loud-
speaker output (see the section "Bridged loudspeaker
connections"). The setting options of the integrated DSP
(Digital Sound Processor) cannot be used in this case.
DSP sound settings (FRONT)
A variety of options is available to optimise the sound of the
connected loudspeakers:
– GAIN control (FRONT)
The GAIN control is used to adjust the input sensitivity
of the power amplifi er to the output voltage of your car
sound system preamplifi er output. The adjustment range
is from 0.2 V to 5 V. If a car sound system of a third party
manufacturer is connected, the input sensitivity must be
adjusted corresponding to the manufacturer data.
A few important explanations in this context:
By turning the GAIN control clockwise, the input sensitivity
of the amplifi er and, therefore, also the volume increases.
However, this is not a volume control. In the end position,
it is not possible to achieve a higher amplifi er output, even
if it sounds like that at fi rst. The system merely increases
the volume faster if the volume control of the car sound
system is turned up.
– FULL/HI/LOW switch and X-OVER control (FRONT)
For the GTA 270 DSP, the type of frequency crossover
("Low-Pass" or "High-Pass") and the desired cut-off fre-
quency can be adjusted for the connected loudspeakers.
Select the cut-off frequency up to which lower frequencies
(high-pass) or higher frequencies (low-pass) should be
blocked. Only frequencies above the cut-off frequency
(high-pass) or below the cut-off frequency (low-pass) are
passed on to the loudspeakers.
The cut-off frequency is dependent upon the frequency
range of the loudspeakers (see recommended frequency
range of the loudspeakers).
"High-Pass" (switch setting: HI)
With a setting of 80 Hz, the amplifi er has a frequency range
from 80 Hz to 30,000 Hz.
"Low-Pass" (switch setting: LOW)
This control is active if the switch is in the LOW position,
and allows for setting the desired entry frequency.
Example:
At a setting of 80 Hz, the amplifi er has a frequency range
of 10 Hz to 80 Hz.
GTA_270_DSP_13LG.indd 7
GTA_270_DSP_13LG.indd 7
"Full Range" (switch setting: FULL)
In this switch setting, the frequency control is deactivated
and the entire frequency spectrum is being amplifi ed.
– SUBSONIC control (FRONT)
To avoid interferences from extremely low frequencies,
you can use the subsonic fi lter to limit the low-frequency
response of the device. The setting of the subsonic fi lter
suppresses all frequencies below the defi ned frequency.
Example:
At a setting of 40 Hz, the frequency range from 0 Hz to
40 Hz is being suppressed.
DSP sound settings (SUBWOOFER)
The following options are available to optimise the sound
for the use of a subwoofer:
– X-OVER control (SUBWOOFER)
For the GTA 270 DSP, the type of frequency crossover
("Low-Pass") can be adjusted. Select the cut-off frequency
up to which higher frequencies should be blocked. Only
frequencies that are below the cut-off frequency are
passed on to the loudspeakers.
Example:
At a setting of 80 Hz, the amplifi er has a frequency range
of 10 Hz to 80 Hz.
– SUBSONIC control (SUBWOOFER)
To avoid interferences from extremely low frequencies,
you can use the subsonic fi lter to limit the low-frequency
response of the device. The setting of the subsonic fi lter
suppresses all frequencies below the defi ned frequency.
Example:
At a setting of 40 Hz, the frequency range from 0 Hz to
40 Hz is being suppressed.
– PHASE control (SUBWOOFER)
This control allows the stepless change of the phase posi-
tion of the subwoofer from 0° to 180°. It is used for the
fi ne tuning with the other connected loudspeakers and if
set correctly, it can prevent any possibly occurring mutual
cancellation of low frequencies within the audio system.
FRONT COMPRESSOR and SUB COMPRESSOR
switches
This function is used to protect the connected loudspeakers
and subwoofer. If the switch is in the ON position, the out-
put volume is reduced by 10 dB. The GTA 270 DSP features
separate switches for the connected loudspeakers (FRONT
COMPRESSOR) and subwoofer (SUB COMPRESSOR).
FRONT dB/Oct and SUBWOOFER dB/Oct
switches
These switches are used to set the attenuation of the in-
stalled filter separately for the connected loudspeakers
and subwoofer. A high value ensures a steep fi lter slope,
which translates to a strict separation between blocked and
forwarded frequencies. A low value ensures a soft separa-
tion, which translates to a gradual transition from blocked
to forwarded frequencies. The settings 18, 24 or 48 dB per
octave are available for attenuation.
Caution:
If the FRONT switch is set to FULL, the FRONT dB/Oct
switch is without function.
GTA 270 DSP
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