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Atlantic Technology Innovations for In-Wall Loudspeakers
Low-Resonance Tweeter (LRT™) and Directional Vector Control (DVC™)
It is obvious that people choose in-walls
because they don’t want to see speaker
boxes in their room. Furthermore, most
people mount in-walls high off the floor—
above the sight line—again, because
people don’t want to see the speakers. The
result of this is that much of the sound is
focused above the listener's head and
distorted in terms of the frequency
response balance of the sound reaching
the listener's ears.
Previous attempts to compensate for this
non-optimal positioning have used some
variant of the “pivoting tweeter” approach.
But pivoting tweeters don’t work
very well.
Here’s why: two-way tweeters cross over
too high in frequency—about 3,500-4,000
Hz—so it is the woofer, not the tweeter,
that plays most of the midrange, and it’s
the midrange that your ear uses to
determine directionality.
Woofers beam badly in the upper
midrange. If the woofer is above ear level,
it’s going to beam the upper midrange like
a flashlight right over the listener’s head.
The so-called “pivoting tweeter” is not
much help, because it doesn’t play the
midrange! And to make matters worse,
when you pivot a tweeter, you introduce a
ledge or shelf that diffracts the tweeter's
output and smears the propagation of the
treble frequencies.
It’s a messy,
inelegant solution
that probably does
more harm than
good.
So here’s what we
did instead: We
modified our
tweeter so it can
play lower
frequencies; far
down into the midrange, about a full octave
lower than a conventional tweeter to
around 2,000 Hz. It’s a very highly-
engineered tweeter system with a vented
backplate, playing into its own sub-
enclosure (complete with internal stuffing!),
and special heat-sinking. We call it the
Low-Resonance Tweeter (LRT™). Now the
woofer doesn’t have to struggle to reach
into the upper midrange, and we get a
much smoother blend of radiation
coverage angles as we transition from the
woofer to the tweeter.
One of the characteristics of speaker
performance is what engineers call
“lobing.” A speaker’s output will lobe up or
down, depending on things like crossover
topology, driver positioning, etc. It can be
very frustrating to develop, say, a new 35-
inch tall floor-standing speaker and find