ROCKFORD FOSGATE T1D412 SUBWOOFER AS SEEN IN ISSUE ...

R O C K F O R D F O S G AT E T 1 D 4 1 2 S U B W O O F E R AS SEEN IN ISSUE 12.10

ROCKFORD FOSGATE T1D412
CHECK
THE SPECS
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Rockford Fosgate T1D412 at
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rockfordfosgateT1D412
ROCKFORD FOSGATE
the Rockford customer service rep wasn’t kidding,
this thing hauls the mail! In the vented enclosure
with an 800 watt amplifier I had more output than
the rest of my system could keep up with. Dialing
back the power to the sub a bit allowed me to concentrate
more on how it sounded. This woofer loves
to play low and loud. Songs with very low frequency
information, such as Avril Lavigne’s “Sk8ter Boi” or
Yello’s “Unbelievable” really showed the woofer’s
capability in a vented application, and I immediately
understood why so many people choose it. Even with
the faster roll-off of a vented box, the deep bass had
tremendous authority and realism. Kick drum notes
were clean and well defined, and the bass in general
was natural and warm sounding.
As usual, curiosity got the better of me, and I
changed to a 1.5 cubic foot sealed enclosure. Now, the
deep bass was even deeper than before, and easily
audible down to 20Hz. But what I really appreciated was
how good this big power happy subwoofer could actually
sound. In the sealed enclosure the woofer’s realism
and definition improved notably, and if I were to use this
woofer in my vehicle, I’d choose the sealed enclosure.
WWW.ROCKFORDFOSGATE.COM
But the cool part is, you can have it both ways
with a single woofer, simply by changing the
enclosure. If loud and proud is your thing, the
vented box is the way to go, but if articulate, deep
bass approaching audiophile quality appeals to
you more than rattling windows 2 blocks away, the
sealed method is for you. Either way, the T1D412
will not disappoint.
CONCLUSION
If you think a subwoofer is a subwoofer and
there’s nothing new in the zoo, give your head a
shake and check out the T1 woofers from Rockford
Fosgate. While they certainly incorporate high tech
features and great looks, the thing I liked most
about the T1D412 was that it’s clear the company
has not forgotten what made them famous in the
first place, and is still turning out the kinds of products
that their customers expect. And in the case
of the T1D412, that’s authoritative bass that will
make you the envy of the neighborhood, with
a torture-tested design that ensures reliability and
long lasting performance.

T
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R E P O R T
ROCKFORD FOSGATE
T1D412 TEXT
AND MEASUREMENTS BY GARRY SPRINGGAY
SUBWOOFER REVIEW
n the high performance car audio world, the Rockford Fosgate brand has certainly made a name for itself as the originator
I of such legendary products as the Punch 45, Power 650, Symmetry, and the industry’s first dual voice coil woofers back
in 1989, and they continue to be a leader in product innovation and technology. And while most of us tend to think about
electronics when those terms are used, the company also pushes the technological envelope when it comes to their speakers and
subwoofers. A perfect example of what I’m talking about was delivered to our lab in the form of the Rockford Fosgate Power Series
T1D412 subwoofer.
FEATURES
The Rockford Fosgate T1D412 subwoofer is loaded with trick and
cool innovations that make the woofer easier to install, and improve its
performance. The first thing you notice when you take the woofer out of
the box is that it has an unusually shaped surround. Unlike the popular
wide, fat rolled surrounds, the T1 woofers use a tall, narrower surround.
The reason is to not only maximize the woofer’s excursion capabilities,
but also to maximize the amount of cone area available. After all,
the more air you move, the more bass you’ll have, and Rockford calls
this ingenious (patent pending) surround “VAST”, which is an acronym
for “Vertical Attach Surround Technique”. The idea behind VAST is to
eliminate the large flat area that is usually used to secure the surround
to the cone, thereby increasing cone area, and output. The “cone” that
you see and that actually moves air is actually a large aluminum dustcap,
which provides a smooth concave look, and helps to dissipate heat from
the voice coil assembly. The dustcap/cone assembly is actually driven by
a Kevlar reinforced paper cone which can be seen by looking through the
open areas of the die-cast aluminum basket. In the interest of maximum

heat dissipation, black anodized aluminum is used for the 3-inch
former, on which dual voice coils are wound with copper-clad aluminum
wire. Another trick technology is used to dissipate even
more heat, this one is called “IDHS” which stands for Inductive
Damping Heat Sink.
Attached directly to the top surface of the nearly 8 pound
magnetic motor, the copper heatsink not only is finned to disspate
heat from the magnetic material, but it is also used to
reduce distortion and back EMF (Electro-motive Force) from
the woofer, which leads to better sound and improved reliability.
Rockford Fosgate has gone to great lengths to ensure the
T1 woofers will tolerate the sort of abuse their typical customer
will put the product through. To this end, even the tinsel leads
have received special attention by stitching them to the spider
in multiple points. This allows each tinsel lead to have reduced
mass, and spreads the stress over a much larger area, resulting
in a more robust electrical path to the voice coils.
Those of you who struggle with remembering your series and
parallel wiring methods and formulas will appreciate the really
trick and very handy “SWIFT” terminals. Short for Selectable
Woofer Impedance Fused Termination, the SWIFT terminals
allow almost instant selection of either 2 or 8 ohm wiring,
and best of all you connect both the voice coils with a single
positive and negative wire. The impedance selection is done by
simply rotating a special center plug that’s clearly marked for
the intended impedance. Once in place, the jumper plug also
provides fused protection from severe or accidental overloads.
Wire connections are handled by slickly integrated spring
loaded terminals that will accommodate up to 8 gauge cables.
And to cap the whole thing off, included in the box is a special
trim ring and removable heavy-duty steel mesh grille that
looks terrific and really trims out the woofer.
When it comes to reliability, Rockford Fosgate goes to great
lengths to ensure the products exceed the expectations of even
their most enthusiastic customers. To that end, the T1 woofers
not only meet the stringent CEA-2031 standards, but the
design also has to pass a brutal 24-hour full-power torture test
before it is approved for production.
LISTENING
After the normal break-in procedure, I read through the owner’s
manual and visited the Rockford Fosgate website for direction
regarding the enclosure. I quickly learned that the T1 woofers
can be used in either sealed or vented enclosures, but are
not recommended for infinite baffle applications. A quick call to
the RF tech support line revealed that while the T1 woofer really
leans slightly towards a preference for a sealed enclosure,
most of the customers buying them are after loud bass, and for
that, the vented enclosure rules. So, because most people use
them in the vented application, I decided to try that approach
first. I just happened to have the recommended 1.75 cubic foot
enclosure in my inventory of sub boxes, so I loaded the T1D412
into it, and connected the woofer to my reference system. Man,
For additional tech info and high resolution
performance graphs of the measurements, visit
www.pasmag.com/RockfordFosgateT1D412
Woofer in a 1.75 cubic foot vented enclosure.
Impedance of the woofer – Free-air.
Impedance of the woofer in the 1.75 cubic foot vented enclosure.
This is the impedance curve that the amplifier “sees”.