Legacy Audio Signature SE - Manual (Page 24)

LEGACY Audio has been benefiting from low mass ribbon and leaf drivers since 1984. I have a col-
lection of ribbon tweeters from the world over and always loved the way good ribbons reproduced
the swishing sound of brushes on a snare- and the simple honesty in the reproduction of strings
without imparting an edgy ringing effect found in most tweeters. There’s just something right about
the sound – like a C12 mic capsule. If one could increase the dynamics to natural levels and extend
the range of ribbons without beaming undesirably, the benefit would be considerable musically.
I have always been a proponent of low mass, high acceleration drive elements. The acceleration
capability of the drivers ultimately determines the transient or waveform tracing capability of the
loudspeaker. To build a better speaker, one MUST first acknowledge that loudspeakers are dread-
fully slow by nature. Their responsiveness lags the electrical waveforms settling time
by orders of
magnitude (Logically so, if one contrasts the mass of an electron to the mass of a speaker dia-
phragm.).
Typical of transducers (devices that convert one form of energy to another), speakers are also
ex-
tremely inefficient -wasting more than 98% of their input power in the form of heat and out of
phase motion.
For these two reasons I have been working with speaker driver motors with magnetic field strengths
as high as 2 Tesla (60,000 times the field strength of our planet Earth) to overcome these limita-
tions. With such field strength, greater levels of articulation are possible at the lower limits of a
transducer. For example, the reproduction of a simple strike of a heavy anvil will reveal tones that
are richer, darker and more complex than otherwise possible.
In 2006 Legacy Audio introduced our first air motion transducer; a modernized version of the AMT
tweeter developed by Oskar Heil in the 1970s. Legacy’s first version utilizes a folded Kapton (not
mylar) diaphragm and R45 neodymium wafers instead of ceramic magnets. The result was higher
efficiency and greater power handling. This translated to significant gains in dynamic range and
reduced distortion. We soon adapted an existing 4” planar ribbon (the one with the round faceplate)
to work in conjunction with this tweeter to facilitate the voicing of the hand-off to our 7” driver.
Continuing the Pursuit of Perfection
(Legacy Air Motion Ribbons)
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