DECWARE
IMPERIAL S.O.
(sub-only)
One of things an
Imperial always did better
than every other speaker was low bass.
Unlike our implementation
of the original Imperial, Steve
Deckert designed this one specifically as
a sub-woofer. It
uses a radical new concept in horn theory to
accomplish an end result
that's nothing short of spectacular!
How does it work?
The Imperial horn
flare was designed to bend waves up to 600
cycles making it very
efficient up to that frequency. When
used as a sub-woofer, even
with a 24dB per octave active crossover, you
can still hear vocals down
in the horn flare. Not a problem in a
large commercial venue, but
in a private listening room the close
proximity to the listener makes
it possible for this low level information to
be heard thus polluting
part of the sound of your main speakers.
To eliminate this and
other problems, the
design of the horn has been completely changed
so that the horn flare
resonates at low frequencies with no high
frequencies ever getting down
inside the throat. Rather than
rear-loading the woofer as in the
original Imperial, the Imperial S.O. has the
woofer running in a sealed
cavity and the front of the driver is rather
esoterically loaded to
bias it's output towards the throat. The
throat is exposed to the
room taking the shape of a narrow slot and
achieves a resonance just
like a beer bottle would with wind blowing
past it's top only at a much
lower frequency.
It is possible with
the right driver to run
these cabinets full range with no crossover
giving a nice blend into a
high efficiency full range speaker. Even
when running the driver
full range, you can crawl into the mouth of
the horn and still hear no
mid bass, mid-range or treble. This
results in really clean bass
and ensures nice black backgrounds with any
type of music.
Another advantage of
this design is that it
will function better in a small room.
Having the driver in a
sealed box and pre-loaded against a variable
rate slot also protects
the it from getting loaded up from
the room. This
concept in part came from Decware's car audio
enclosures such as the
Deathbox, where results became predictable
from car to car.
Another benefit of
the design is that it also
significantly reduces sympathetic resonance's.
Shown below is the
Decware implementation of the original
Imperials configured as subs.
As you can see, with woofers exposed to
the room and the flare of
the horn, they are bound to resonate with any
low frequency sounds in
the room. When I listened to speakers
placed in front of
it, I seldom hooked an amplifier up to it
because it made plenty
of bass all by itself.
With the new
Imperial S.O. design, this
problem has been practically eliminated,
allowing you to hear what a
given pair of speakers placed in this room
might actually sound like on
there own. Compared to the picture
above, the S.O. design is a
far cleaner sounding bass with a noticeably
lower hit. You can
find tons of tech-talk about this design in
our support forum.
support
forum
The
plan above is available as a
large hi-res gray-scale image that can be
viewed online or
downloaded and printed.
PLANS CAN BE
DOWNLOADED FOR $19.95
Decware
Imperial S.O. Plans
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trademark of High Fidelity
Engineering Co.
Copyright
© 1996 1997 1998 1999 2000
2001 2002 2003 2004 2005 2006 2007 2008
2009 2010
by Steve Deckert
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