NITID S12WP Dec 2022
7 Amate Audio
The typical operating range of a traditional subwoofer tends to be like a monopole,
i.e. tends to radiate with the same energy in all directions. This behaviour implies
that the control of radiation at low frequencies is very difficult because the
wavelengths are very large compared to the size of the source (8.5 m at 40Hz).
To increase the directivity at low frequencies we
must transform the omnidirectional performance
into a cardioid performance. This can only be
achieved by various sources, arranged in a
certain position, to which we apply a specific
phase, filtering and delay. That is, we need to
reproduce two signals with the same frequency
and similar amplitude which will have a difference
in phase of approximately 180º at a certain point
of the sound field. If the phases and delays are
well calculated, the result is a system, in which
we cancel the energy of the back and not the one
of the front.
Fig. 6. Cardioid pattern
4.1. The CARDIOID presets
The S12WP can generate an uncompromised cardioid behaviour when used in
conjunction with an external Amate Audio processor and their correct set-up
parameters. In its minimum and standard configuration a Cardioid setup consists of a
stack of three subwoofer cabinets.
Only one subwoofer is needed to compensate for the energy of the other two
radiating to the front. Then, the cabinet facing to the back (to the stage) should be
located in the centre of the column.
Fig. 7. Cardioid configuration for S12WP subwoofer
