Monitor Audio PL100 STAND Platinum series, Owner'S Manual

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RDT
®
(Rigid Diaphragm Technology) Mid-range and Bass Drivers
The bass and mid-range driver cones use RDT, a unique technology developed specifically
by Monitor Audio’s engineers for the Platinum series loudspeakers.
Designed to reduce mass and increase cone stiffness, RDT applies ultra-thin skins of C-CAM
to a core of honeycomb Nomex material, creating a structure which is extremely light but
more rigid than a steel plate. At only 40μm thick, the C-CAM skins are half the thickness of
a human hair, yet when bonded to the hexagonal honeycomb core they form an RDT cone,
which is 150 times more rigid than a single layer of 200μm C-CAM alloy, but with a fraction
of the overall mass. These properties allow the cone to operate as a lightening-fast piston
for a clearer more natural sound. The cone’s new concave geometry has been refined by
FEA engineering to provide a smooth frequency response and eradicate break-up.
To optimise the performance of the RDT cone, Monitor Audio has developed motor
systems in which a focused magnetic gap and copper eddy rings work together to
produce a higher level of linearity and lower distortion than was previously possible.
Magnet plates and poles are CNC machined to very precise standards in order to provide
ultimate consistency.
The Platinum mid-range driver utilises an ‘under hung’ voice coil design to further
optimise linearity and reduce distortion. High energy NeFeB rare earth magnets are used to
provide high efficiency and a large 2” (50mm) voice coil is specified to handle high power
input and dynamic impulses. Its RDT cone is directly driven by the voice coil to provide a
seamless mid-range and a natural integration with the bass and high frequency drivers.
The Platinum bass drivers use long-throw voice coil windings to provide large excursions
at high power levels. The 8” (200mm) bass drivers employ dual spider arrangements to
provide stability at high excursions. Their direct-drive RDT cones have no dust cap or joints
to interfere with the driver response over the working band.
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