DECWARE IMPERIAL S.O.
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
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.
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
Imperial S.O. Plans
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Decware is a trademark of High Fidelity
Copyright © 1996 1997 1998 1999 2000
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
by Steve Deckert