5 :
F u n c t i o n s / S e t t i n g s – C 1 S u b
The C1 Sub amplifier control panel is shown in
Figure 2
.
Mounted on the panel are three rotary knobs enabling
adjustment of Level, Low Pass Crossover Frequency and Phase.
Located next to the phase knob is a in/out phase switch.
Overall input sensitivity
of the Subwoofer can be set via the
Level rotary knob and should initially be set towards the centre
of its range (12 o’clock) and only adjusted once the upper filter
cut-off frequency has been set.
Filter Frequency
is controlled via the Frequency rotary knob.
The filter frequency is the fundamental parameter that defines
how the subwoofer integrates with the satellite/main loud-
speakers. The filter frequency should be set at, or just above the
cut-off frequency of the satellite/main loudspeakers. The
recommended initial filter settings for the C1 Sub when used
with ATC satellite/main loudspeakers are shown below:
SCM7 – 60Hz; SCM11 – 55Hz; SCM19 – 55Hz; SCM40 – 50Hz
HTS7/HTS7C – 55Hz; HTS11/HTS11C – 50Hz; HTS40 -50Hz.
Phase
is adjusted using a combination of the Phase rotary knob
and the in/out switch. These controls change the phase of the
acoustic output signal with reference to the input signal. This can
be used to improve the integration of the sub – satellite/main
loudspeakers by correcting for phase problems due to different
distances from listener to sub and satellite/main loudspeakers.
This control can be set by listening to well-known material and
choosing the preferred setting or, by using a test tone. If using
the test tone method, select a tone at, or very close to the sub-
satellite crossover frequency and play it back through the sub
and satellite loudspeakers. Flip the in/out phase setting and
rotate the knob to listen to which gives the highest total output
at the listening position. Alternatively, a sound level meter could
be used to measure the level
L+R Output
provides a line level summed output of the left
and right input signals. This can be used to “Daisy Chain” C1
subwoofers together. There are no limits to the number of C1
Subwoofers that can be connected in this manner. The control
panel settings have no bearing on the output, i.e the output is
unfiltered and as such each Subwoofer in the chain will require
independent setting of Level and Phase.
Standby/Limit.
A single Bi-Colour LED is mounted on the
front panel of the C1 Sub. When the loudspeaker is powered on,
the LED will illuminate Green. The amplifier in the C1 Sub
employs ATC's Active FET momentary gain reduction protection
circuitry which when activated will cause the LED to blink red.
This circuit ensures that when driven to overload the amplifier
will clip in a soft manner, minimising typical limiter related
distortions. If the Power/Limit LED is regularly blinking Red, the
Level is too high and should be reduced, either on the Control
Panel or at source.
ENTRY MANUAL 040919_ENTRY BROCHURE 13.3 10/09/2019 15:19 Page 18