Sunfire Home Theater System - Manual (Page 5)

5
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Your Sunfi re Subwoofer is designed to
give you the best possible low-fre quen cy
sound quality for your Home Theater ex-
pe ri ence. It in cor po rates a tre men dous ly
powerful built-in am pli fi er and a pair of
drivers to produce tight, fl oor-rumbling
bass down to 22 Hz, that you can feel as
well as hear.
The subwoofer has an adjustable high
cut fi lter and a choice of speaker-level
or line-level inputs for easy in cor po ra tion
into existing systems, or as part of a
subwoofer/satellite speaker com bi na tion.
Controls for adjusting the volume,
crossover frequency and phase, allow
the subwoofer to be perfectly matched
to any listening environment and audio
components.
The Drivers
To have lots of bass requires moving
lots of air. Your Sunfi re Subwoofer incor-
porates two drivers that can move back
and forth ap prox i mate ly fi ve times more
than a normal sub woof er. This gives it a
lot of air moving capacity which allows for
majestic bass per for mance.
Two drivers share the acoustic output.
Sometimes one driver appears to be
moving more than the other. They both
move the same amount only when op-
erating at the limit of their ex cur sion and
power output, or when bass requirements
and music re quire ments demand maxi-
mum output from the system. Otherwise,
the power is shared between the two
drivers in a way that depends on the mo-
mentary am pli tude and the mo men tary
musical spectrum. It is normal for one or
the other to move more or less than its
mate during operation.
On the driver to the right of the control
panel there is a slight bump, under which
is a pressure cap. The bump is normal.
The driver on the left is ab so lute ly fl at
and very rugged. The one with the slight
bump is not quite as rugged, and modest
care should be taken with it, though it is
still very strong. During installation, you
should position the driver with the bump
towards a protected side.
The Amplifi er
The large movement range of the driv-
ers creates greater air pressure inside
the box than a con ven tion al woofer.
There fore, the drive am pli fi er must be
much more powerful than an or di nary
woofer amplifi er. In fact, it has to be so
powerful that it is almost hard to believe.
The power amplifi er within your Sunfi re
Subwoofer is capable of de liv er ing over
1,500 watts into a 4.6 ohm resistor (the
voice coil re sis tance of the subwoofer’s
driver). When the same full output is ap-
plied to the driver, however, the enor-
mous back-elec tro mo tive force gen er at ed
as a con se quence of its large motion and
giant magnet causes the current fl ow to
be much less than if it were a 4.6 ohm
resistor. It is this singular property of the
driver that allows the woofer to be ap-
prox i mate ly ten times more effi cient than
a woofer this size would nor mal ly be.
Hence, the actual average input power is
substantially less than 1,500 watts, and is
ap prox i mate ly 120 watts for most musical
material on the loudest pas sag es.
A compressor circuit kicks in au to mat i-
cal ly if the input signal level reaches a
level that would overload the driver. This
maintains a ceiling on the output without
clip ping. If the input signal is driven even
further, a ‘soft clipping’ circuit is enabled.
This allows the woofer to put more sound
into the room to satiate the power hungry
user, but without distortion or damage to
the woofer. Thus, for explosive scenes
in movies, this pro duc es extremely high
sound pressure levels (SPL) in your room
without the woofer banging against its
mechanical stops.
For more details of the subwoofer de-
sign, please call us or view our website:
www.sunfi re.com
Overview