18s ND3SA 8 Ohm

The ND3SA 1.4 inch exit neodymium high frequency compression driver has been designed for high
level sound systems application. The unit has been developed to fulfill tight geometrical
requirements, thanks to its ultra compact 120mm overall diameter.
The diaphragm assembly is composed by an aluminum dome sandwiched to a proprietary treated
PEN (polyethylene naftalate) suspension. This design maintains low resonance and, when compared
to the titanium version, lowers the minimum crossover point value at 1000 Hz.
The composite diaphragm assembly is made by an aluminum dome strongly joined to the PEN
suspension, in order to assure unmatched transient response. The lower density of the aluminum
and PEN structure permits higher levels of sensitivity, especially in the mid-high frequency range. A
bended former edge-wound aluminum 75mm voice coil completes the diaphragm assembly.
In comparison with a usual straight former joint, the ND3SA moving assembly design assures
extended frequency energy transfer for improved response linearity and unparallel reliability. This
feature facilitates proper motion control of the dome in real working conditions. A proprietary treated
Nomex former is used as Nomex shows a 30% higher value of tensile elongation at a working
operative temperature (200°C) when compared to Kapton. Moreover, this proprietary former material
is also suitable for use in higher moisture content environments.
The diaphragm kit self centering design allows high precision mounting and at the same time makes
very easy the servicing procedure.
Despite of its compact size, the ND3A neodymium magnet assembly has been designed to obtain
20KGauss in the gap for major benefits in transient response. The motor structure, throughout the
precisely coherent metal alloy phase plug with 4 circumferential slots and copper ring on the pole
piece, reduces inductance effect and distortion.
The ability to perform properly under inclement weather conditions is a key point of the Eighteen
Sound philosophy. Hence, a special treatment is applied to the magnet and the top and back plates
of the magnetic structure in order to make the driver more resistant to the corrosive effects of salts
and oxidization. This treatment is more effective than any other coating commonly used.