Nexo GEO D - Manual (Page 67)

NEXO NX242 D IGITAL C ONTROLLER FOR GEO D AND GEO SUB Page 67/97
6 NEXO NX242 D
IGITAL
C
ONTROLLER FOR
GEO D
AND
GEO SUB
IMPORTANT
GEO SUB and GEOD10 use latest NEXO proprietary sophisticated DSP algorithm, which
require additional resources from the NX-Tension ES4 Card. All available GEO SUB and
GEO D10 setups require that NX-ES4 card is installed in NX242 TD Controller.
6.1 NX242 Proprietary Functions
The NX242 is much more than a “generic” Digital Signal Processor. It provides all the standard
functions that you expect from this type of unit, but its real value is the interface between you and your
speaker system. The NX242 includes a number of proprietary functions, developed and refined during
NEXO’s 20 years of loudspeaker development experience, to ensure that your PA delivers maximum
performance and reliability.
6.1.1 Upgradable Firmware
NEXO releases regular firmware updates. Each new release is the result of our ongoing R&D program
combined with user feedback from the field. New firmware releases can include new setups for different
combinations of NEXO full range loudspeakers and subwoofers, improvements to existing setups, and
new software functions. The NX242 is thus evolving with each of those releases, profiting from the
latest discoveries of NEXO’s R&D department as well as the experience of NEXO users.
6.1.2 EQ & Filtering
Subsonic and VHF filtering
Low and high-pass filters are used to filter out frequencies that could possibly degrade the performance
of the TDcontroller and amplifiers. The filters are optimised to work in conjunction with overall system
response.
The high pass filters are also extremely important as they help control excursion at very low
frequencies, which is a major feature for system reliability. This is one of the main reasons to avoid
using setups which are not designed for the cabinet you are using.
Equalising acoustical response
NEXO loudspeakers are acoustically designed for maximum efficiency over their operating bandwidth.
The NX242 provides the correction required to obtain a flat system response. 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 can also extend a NEXO
loudspeaker’s frequency response, especially at low frequencies where acoustical performance is
limited by cabinet size.
While many DSP processors can provide this type of EQ, none can include the extensive measurement
facilities and listening tests employed by NEXO R&D when adjusting NX242 setups for a particular
loudspeaker.
Crossover section
Crossover between different bands is tuned for every set-up of every cabinet. The crossover is
designed to ensure the best phase alignment possible throughout the crossover overlap region.
Each crossover is “made to measure” in order that each transducer can fit with its neighbour by
achieving a perfect phase alignment. Unconventional filters are used, ranging from 6dB/octave to near
infinite slopes depending of the type of crossover wanted. Time alignment is also performed in an
unconventional way, by using the crossover filter group delays in combination with allpass and/or
frequency dependent delays.