Amate Audio NITID N18W, User Manual

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NITID N18W_N218W Oct 2017
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Amate Audio
To get back to the normal operation mode, the input level should be reduced to
below 2 Vrms. After the level reduction, the system needs about 5 seconds to
recover the normal operation mode.
5. CARDIOID SUBWOOFERS
N18W and N218W enable the combination of three or multiple of three subwoofer
cabinets in an array to provide exceptional directivity at low frequencies. High
directivity at low frequencies has two main effects on the sound field: firstly, the low
frequency level behind the subwoofer cabinets is greatly reduced; secondly, in
closed venues the diffuse sound field at low frequencies is reduced so the low
frequency reproduction is much more precise.
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).
Fig. 19. Traditional polar pattern of a subwoofer 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.
This can only be achieved with cabinets that incorporate
independent delay units on their DSP, as N18W and
N218W.
Fig. 20. Cardioid pattern
5.1. The CARDIOID preset
N18W and N218W can generate an uncompromised cardioid behaviour, which
means that there is no need for special cabinets, enabling the use of the system’s full
efficiency with just “one finger”.
n its minimum and standard configuration a Cardioid setup consists of a stack of
three subwoofer cabinets (for N18W) and of a horizontal line of three subwoofer
cabinets (for N218W).
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.