Sunfire Home Theater System User Manual

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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