SDD3 · Setup
Menu
Units mode
Delay mode
Delay can be set in time (miliseconds) or in distance (meters
or feets depending on Units setup). When switching between
time and distance, the delay time is kept and recalculated
to each other. The delay distance depends on the ambient
temperature.
Units
It is possible to switch between metric (meters, °C )
and imperial (feet, °F) units, when switching between each
other, the distance is maintained.
Link AB
It is possible to link channel A and B delay setup, when both
delays are the same. When switching to Link AB, the delay
of both channels is set by channel A.
Subwoofer mode
Cardioid setup
Bass is usually omnidirectional but by using a cardioid
bass array you can reduce bass feedback on stage and also
minimise noise pollution from events. When using cardioid
mode, the front subwoofer is 1/4 wavelength of the tuned
cardioid frequency in front of the rear subwoofer. The front
subwoofer is fed with a 1/4 wavelength delay compared to
the rear sub. This configuration results in a cardioid polar
response ,(because of addition and subtraction of
the subwoofer signals).
SDD3 · S
etup
11
Cardioid polar characteristics
FRONT
SUB
REAR
SUB
Cardioid calculation - example
Subwoofers distance (d) corresponds to 1/4 wavelength
(λ) of the tuned cardioid frequency (f).
Speed of sound (v) varies with temperature, for 20°C
is approx 343m/s.
λ = 1 / 4f
d = v * λ
