5
TECHNICAL DESCRIPTION
The Eminent Technology Linear Field Transducer (LFT) is a full-range, push-
pull, dynamic planar loudspeaker. In a sense, it is the magnetic equivalent of a
push-pull electrostatic loudspeaker, differing in that it requires no step-up
transformer or bias voltage, and that the audio signal is applied directly to its
diaphragm.
THE LFT-12
A REVIEW OF PREVIOUS LOUDSPEAKER TECHNOLOGY
To fully understand the strengths of the LFT design, one must first consider the
design and operation of this speaker's three most notable antecedents: the push-pull
electrostatic loudspeaker (ESL); the traditional, single-ended planar magnetic
loudspeaker, and the ribbon loudspeaker.
THE ELECTROSTATIC LOUDSPEAKER
The electrostatic loudspeaker is constructed with a very thin (half mil or less) diaphragm
made of Mylar or a similar material, to which a light coating of mildly conductive substance such as
graphite has been applied. This diaphragm is suspended on a rigid frame and sandwiched between
two stationary conductive grids (usually perforated metal plates) called stators.
FRAME
REAR STATOR
RESISTOR
TRANSFORMER
+
--
TO
AMPLIFIER
TO BIAS
VOLTAGE
SUPPLY
[PERFORATED
METAL PLATE]
FRONT
STATOR
CONDUCTIVE
DIAPHRAM
ELECTROSTATIC LOUDSPEAKER
[TOP VIEW CROSS SECTION]
