Equalising Wideband Acoustical Response (3); User Set - Up , Array Eq (4); Equalising Single Component Response And Nxstream Processing (5); Crossover Section (6) - Yamaha Nexo NXAMP4X4 User Manual

BLOCK DIAGRAM DESCRIPTION
The high pass filters are also extremely important as they optimise excursion at very low
frequency which is a very important safety factor. (Therefore do not use set-ups which are
not designed for the cabinet you are using).

Equalising wideband acoustical response (3)

This wideband equaliser section achieves the correction required to obtain a flat system
response, as the cabinets are acoustically designed for maximum efficiency on the whole
frequency range. Active rather than passive attenuation allows the lowering of amplifier
voltages for a given output SPL and therefore increases the maximum SPL achievable with
the same amplifier. Active equalisation also extends system band pass especially at low
frequencies where acoustical performance is limited by cabinet size.
(4)
User set-up, Array EQ
For each channel, an Array EQ is currently implemented in the NXAMP. The cut off
frequency of a low-shelving filter is factory tuned for each cabinet set-up. The user has
access to the gain of this filter. The array EQ is tuned in order to reproduce the effect of the
bass coupling, allowing the user to increase or diminish the effect of the stacking (see
further about the Array EQ menu, or Array EQ setting from ESmonitor).

Equalising single component response and NXSTREAM processing (5)

This equaliser set allows acting on a specific driver after the crossover, rather than on the
wideband section. This allows to EQ one driver without affecting the others (cleaning out of
band response, fine tuning in a crossover...). All the parameters are factory set.
Last generation of NXSTREAM algorithm are also implemented in this section. This process
uses sophisticated DSP program to go beyond the limits of the conventional EQ filtering, to
manipulate for example the phase of the audio signal independently of the amplitude and
so on.

Crossover section (6)

Crossover between different bands is tuned for every set-up of every cabinet. Each
crossover is customized so that each transducer will fit with its neighbor by achieving a
perfect phase alignment. Unconventional, crossover-defined filters are applied, ranging
from 6dB/octave to near infinite slopes according to the type of crossover desired. Time
alignment is also unconventionally achieved, by combining crossover filter group delays
with all-pass and/or frequency dependent delays.

Post protection EQ and low pass (27) (28)

After the Protection block (using VCEQ and VCAs, see bellow), another set of EQ / low pass
filtering is applied to remove some artefacts due to protection algorithm on some speaker
setups.

Gain section (29)

In this section the digital gain is applied to the corresponding channel. This digital gain is
computed by the CPU and depends on the user gain, the setup gain for the channel, and
the optimization of the gain ranging done by the CPU.
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