Eminent LFT-6, Installation Manual

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Eminent Technology’s Linear Field Transducer, introduced as the
LFT, represents a new approach to the design and construction of a
high-quality loudspeaker*. It builds on the strengths of the above
designs while eliminating many of their drawbacks.
The construction of the LFT -6 begins by laminating a very thin sheet of
aluminum foil to a half-mil-thick sheet of Mylar. A voice grid pattern,
created by means of CAD (Computer-Aided Design) technology, is
silkscreened onto the foil side; the remainder of the aluminum--the part not
covered by ink from the silkscreening--is chemically etched away, in a
manner similar to the etching of traces on a printed-circuit board. The ink
is then washed away, leaving a voice grid of near-perfect uniformity. This
technique results in a diaphragm/voice coil grid that is still less than one mil
in total thickness, and also permits relatively narrow spaces between the
individual traces, so the diaphragm can be evenly driven over its entire
surface.
The magnet/frame structure developed for the LFT-6 is also unique.
Eminent Technology builds its strip magnets into individual steel channels,
the size and shape of which have been carefully designed to help “focus”
the magnetic flux lines and concentrate the strength of the magnetic field
on the appropriate area of the diaphragm/voice grid. These channels are
then welded to steel crossbars (four per drive unit, vertically spaced 6-1/2
inches apart), which in turn are bolted to the aluminum frame that holds the
diaphragm in place.
Interestingly, one of the biggest challenges faced in creating a true push-
pull dynamic speaker was not a design consideration but rather a matter of
construction difficulty: to assemble a perfectly rigid structure with very
powerful permanent magnets at the front and the rear, both sides opposing
each other with tremendous force. It was not until Eminent Technology
developed a special method for this assembly procedure that the Linear
Field Transducer became a reality.
* The design and construction of the LFT is patented.
The Linear Field
Transducer
Diaphragm
Construction
The Magnet/Frame
Structure