Polk Audio
dX Series
dX Series
Premium Performance Loudspeakers
Owner’s Manual
dX8 Subwoofer
dX10 Subwoofer
dX12 Subwoofer
Dynamic Balance®Subwoofers
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dX Series
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dX Series
dX Subwoofers—More Bass, Less Space
The dX Series of subwoofers use the latest technologies and highest quality materials to provide you with the best bass response and greatest reliability possible. The
dX subwoofers have been optimized to give the kind of skull-collapsing performance
one would expect from huge enclosures in boxes that take up a fraction of the trunk
space. Some of their design elements are:
• Polymer and graphite composite cones—the stiffest cones in the
autosound industry are able to withstand the enormous pressures generated
inside small enclosures without breakup and distortion.
• High mass cones—allows awesome low frequency tuning in
small enclosures.
• Thick ABS dustcap—prevents distortion due to the build up of air pressure
behind the cap.
• High durometer rubber surrounds—provides a much tighter and more
durable air seal behind the cone than foam, paper or cloth surrounds, for deep,
tight, quick bass. Also, rubber surrounds do not dry rot like the foam surrounds
used by other manufacturers.
• Extra long, precision wrapped, vented coils—for superior cooling
and high power handling.
• Four layer, 2" voice coil—handles the heat generated when your amp is
really cranking.
• Vented pole piece—lets air circulate over the voice coil to keep it cool
and in control even when the bass is really thumping.
• 8 Ohm and 4 Ohm versions available—allows you to choose the
impedance that suits your personal system design, including exotic isobaric
and push-pull types.
Attach your receipt
here and file for future
reference. It may
be required for
warranty service.
X
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Who Is Going To Build Your Subwoofer Enclosure?
Since the subwoofer enclosure is so critical to getting the best performance from your
dX subs, you should ask yourself the following questions:
1. Do I really enjoy working with my hands?
2. Do I have good woodworking and mechanical skills?
3. Do I have, or have access to, woodworking and electrical tools?
4. Do I have a solid understanding about musical reproduction in an automobile?
3 If you answered NO to any of the above questions, we recommend you choose
one of these two possible alternatives: First, there are pre-built subwoofer enclosures
on the market from manufacturers like Q-Logic and R/T, or enclosure kits from
BassLine and others. The second alternative is to have your authorized Polk Audio
dealer design and build a woofer box for you.
3 If you answered YES to all of the above, let’s review some basics before you begin.
Building Your Own Enclosure
The dX subwoofers have been optimized to give you flat bass response in small sealed
enclosures. Some listeners may want response other than “flat,” or may want to trade-off
depth of response for greater efficiency by using a vented enclosure. There is no way we
could provide all the information for all of the options here. This manual will give you
enough information to build a great sounding, small sealed enclosure. If you are interested
in a greater choice of enclosure designs, your Polk dX Series dealer has extensive experience
designing woofer boxes and will be more than happy to work with you. If you prefer, you
can call our Customer Service Department from 9AM to 6PM, Monday through Friday,
Eastern Time at (800)377-7655.
Acoustic Suspension Enclosures
As the dX subwoofers are optimized for acoustic suspension
enclosures, we suggest you use this type of design. The
acoustic suspension cabinet is a sealed airtight box, and
is the easiest box to build. It also is a very predictable
enclosure with easily calculated parameters, and it has a
smooth natural sound. Properly built acoustic suspension
cabinets have a flat frequency response that begins rolling
off at 12 dB per octave at the frequencies below its cabinet
resonance. This works very well inside a car because of a
natural phenomenon called “room gain” or “transfer function”
that gives you a 12 dB per octave increase in bass frequencies. You can
roughly calculate at what frequency this gain begins by using the equation F= 565 / L.
F is the frequency at which bass gain begins, and L is the longest dimension of your
“room.” If, for example, you measured the longest dimension of your car as 5.65 ft., the
room gain begins at 565 / 5.65 or 100 Hz. If your goal was perfectly flat frequency response
you would design your cabinet for this particular car to have a resonance frequency of 100
Hz. Since most people want more bass than a flat frequency response yields, tuning the
cabinet at a lower frequency, say 50 Hz, would give you a gain of 12 dB per octave between
100 and 50 Hz and flat response from 50 Hz down. The larger the cabinet, the lower the
resonant frequency, and the lower the efficiency. Two identical systems will sound very
different in a Honda vs. a Cadillac. The bigger the car the lower the frequency at which
room gain begins.
Tools You Will Need To Build Your Enclosure
If you have decided to build your own enclosure for your Polk dX subwoofers,
here is a list of the tools you should have available to you.
❏Calculator
❏Assorted Drill bits
❏ Screwdriver bit for drill or manual screwdriver
❏ Circular saw
❏ Tape measure
❏Drill - electric or cordless
❏Jigsaw
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Parts You Will Need To Build Your Enclosure
When building a subwoofer enclosure you will find that there are numerous materials
recommended for construction.
1) Medium density fiberboard (MDF)
2) Marine grade plywood
3) Particle board (the smaller the particles the better)
These materials range in price as well as availability. Particle board is the most common,
least costly, and can be purchased at most hardware stores. MDF and marine grade plywood,
although preferable, are usually much harder to find, and much more costly. Whichever you
choose, we recommend that its minimum thickness be 3/4". This will provide the rigidity
necessary for optimum performance.
If you’ve never built an enclosure before we are going to try to make this as easy and
painless as possible. If you’ve built enclosures before you can skip this section and go right
to the technical sheet to get your parameters.
Complete Parts List:
1) Wood (particle board, MDF, or marine grade plywood) 4' x 8' x 3/4" sheet
2) Wood glue (one 12-16 oz. bottle)
3) 1
1/4
"x #8 wood screws (one lb. box)
4) Caulk gun and silicon caulk (two tubes)
5) Terminal cup (one per speaker) available at electronic parts stores
6) Speaker wire (2-4 ft.)
7) Carpet (optional)
8) Grills to protect your subwoofers (optional)
9) Solderless speaker connectors (available at electronic parts stores)
Designing Your Polk dX Subwoofer Enclosure Step By Step
1.) How much room do you have to work with in your car or truck?
When designing your subwoofer enclosure, the first thing you need to figure out is, just how
large an enclosure will fit in your vehicle. When an enclosure is going in the trunk of a car,
you first need to measure your trunk to find the maximum height, width, and depth you
can use. Pay attention to trunk hinges and tension bars. If your enclosure is going in an
area other than a trunk, make sure you check for similar obstructions. After measuring,
subtract 1.5" from each dimension. This compensates for the thickness of the material
you use (simply double the thickness, i.e.: if you’re using 3/4" material, subtract 1 1/2";
1" material, subtract 2", etc), and will give you your usable (internal) dimensions. Record
these dimensions here for future reference.
Maximum dimensions Usable dimensions
Height:__________ inches (Minus 1.5 inches)=______inches
Width:___________inches (Minus 1.5 inches)=______inches
Depth:___________inches (Minus 1.5 inches)=______inches
Usable volume=________cubic inches
Usable volume=________cubic feet
Multiply your usable Width x Height x Depth. The product will be the usable (internal)
volume of your enclosure in cubic inches. Divide this number by 1728 (the number of
cubic inches in a cubic foot). This will give you the internal volume in cubic feet. Divide
your internal cubic feet by 2 (only if you are using a pair of dX subwoofers). Compare
this number to the chart at the bottom of the technical sheet. Choose the recommended
enclosure which is closest in size or that fits your desired type of enclosure. Now that you
have all of your needed dimensions, you can begin cutting your wood. From the above
chart you can tell how big each piece of wood should be.
Here’s a sample enclosure:
Maximum dimensions
Usable dimensions
Height:__________ inches (Minus 1.5 inches)=______inches
Width:___________inches (Minus 1.5 inches)=______inches
Depth:___________inches (Minus 1.5 inches)=______inches
Usable volume=________cubic inches
Usable volume=________cubic feet
15
1/2
"
14"
Hole diameter
dX8 = 7.26
dX10 = 9.30
dX12 = 11.16
28"
29
1/2
"
9"
10
1/2
"
15.5
29.5
10.5
14
28
9
3528
2.042
wood glue in combination with wood screws for the strongest joint. We also suggest that
you use one screw about every three inches along the seams of your enclosure. Assemble
the enclosure as shown in the above diagram but leave one side off. We suggest that you
leave off the baffle board, this will allow you to seal your enclosure more easily, and an
air-tight seal is crucial! The best way to insure an air tight seal is to seal the inside of your
enclosure with quality silicone caulk. This also includes sealing around your input terminal cup, and if you are using a ported enclosure, around your port. It is not advised to use
silicone around your subwoofer when mounting it to the baffle. Instead, we recommend
using the foam gasket weather stripping supplied with your dX subwoofer. When mounting
your subwoofer to the baffle board, pre-drill your mounting holes. This will make the
mounting of your subwoofer easier and will help prevent damage to your subwoofer from
a slip of the drill. When securing your subwoofer to the enclosure we recommend using
bolts and tee-nuts, but if you prefer, you can use wood screws. Whichever you use make
sure they are at least 1.25" long. This will insure a good grip into the wood.
One last thing you could do to your enclosure before installing it, is stuff it. The
primary reason for stuffing an enclosure is to “trick” the woofer into thinking that the
enclosure is larger than it actually is. You would want to do this if you build your box
smaller than the recommended size. By stuffing the box you can build the box as much
as 10% smaller than recommended, and achieve the same net result as the full size
unstuffed box. The easiest way to do this is to use dacron pillow stuffing. It can be bought
from craft stores fairly inexpensively. The rule of thumb for “stuffing” your enclosure is
1 pound of dacron per cubic foot. When putting the Dacron into your enclosure, do not
pack it in, rather place it evenly around the inside the enclosure. When stuffing a ported
enclosure it is important not to obstruct the port or the vent on the back of the sub
with Dacron.
Although your new dX subwoofers were designed to work in a wide variety of enclosures
and configurations, we have included only the most popular ones. For more enclosures and
configurations, please contact your local authorized Polk Audio dealer. We hope that this
manual has helped to take the mystery out of designing an enclosure for your new Polk
Audio dX Subwoofers.
(Refer to insert for recommended enclosure design)
What If I Need Help?
Good luck to you, and enjoy your new Polk dX Subwoofers. If you need assistance or have
any questions, call 1-800-377-7655 between 9am and 6pm, Monday through Friday Eastern
Standard Time.
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By looking at the chart at the end of the technical sheet, you find that this usable
volume is slightly more than double the recommended volume for a single dX10, in
either a sealed or vented enclosure. Assuming that you will be using a pair of woofers,
this will work out well.
If you are using a single subwoofer, you can cut your width in half. Since we will
be using a pair of dX10 subwoofers, for our sample enclosure, we now need to determine
the center divider displacement. This can be figured out by multiplying the height x depth
x thickness of the divider (in our enclosure the thickness of the divider will be the same
as the rest of our enclosure, 3/4") and subtracting that number from the total usable
cubic inches.
You now have all the dimensions you need to begin cutting out your wood. The
illustration on page 7 shows a diagram of the enclosure with all the panel sizes that
need to be cut.
After you have cut all of the wood, it’s time to start assembling your enclosure. Before
you assemble your enclosure there are a few things we recommend doing. You will need
to cut out the hole for your Dynamic Balance
®
subwoofer and your terminal cup, and
pre-drill the holes for your screws. The terminal cup is a connector that allows you to
plug and unplug the wires from your amplifier into the enclosure. You may want to have
a buddy help you with assembly, since it’s hard to hold the pieces together and assemble
them at the same time. When building your subwoofer enclosure we suggest that you use
Affix foam gasket
sections the back of
the basket rim as
shown.
Gasket must be
applied if install
requires a top-mount
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Premium Performance Loudspeakers 11
dX Series
Dynamic Balance® Series Subwoofer Technical Sheet
THEILE / SMALL PARAMETERS
dX8-4Ω dX8-8Ω dX10-4Ω dX10-8Ω dX12-4Ω dX12-8Ω
Freq. Response 20 - 500Hz 20 - 500Hz 20 - 300 Hz 20 - 300Hz 20 - 200Hz 20 - 200Hz
Sensitivity 84dB 84dB 85dB 85dB 86dB 86dB
Impedance (Nominal) 4Ω 8Ω 4Ω 8Ω 4Ω 8Ω
Impedance (Actual) 3.7 8.6 3.7 8.6 3.7 8.6
Max. Power (RMS) 200 W 200 W 300 W 300 W 400 W 400 W
Max. Power (Peak) 400 W 400 W 600 W 600 W 800 W 800 W
Resonant Freq. (Fo, Fs) 30 Hz 34 Hz 28.7 Hz 31.2 Hz 26.3 Hz 26.7 Hz
Qms 6.52 6.99 6.99 7.65 6.71 7.64
Qes 0.48 0.60 0.53 0.70 0.63 0.79
Qts 0.45 0.55 0.49 0.64 0.58 0.71
Vas 14.29L 13.00L 33.4 32.9 79.3 87.5
.51 ft
3
.46 ft
3
1.18 ft
3
1.16 ft
3
2.80 ft
3
3.1 ft
3
Cms 222.5 µm/N 202.3 µm/N 218.1 µm/N 215.3 µm/N 213.1 µm/N 235.3 µm/N
BL 13.4 TM 17.1 TM 13.4 TM 17.1 TM 13.4 TM 17.1 TM
Sd .0214m2.0214m
2
.0330m
2
..0330m
2
0514m
2
.0514m
2
.230ft
2
.230ft
2
.355ft
2
.355ft
2
.553ft
2
.553ft
2
Winding Width 25.4mm 22.9mm 25.4mm 22.9mm 25.4mm 22.9mm
1.00in. .90in. 1.00in. .90in. 1.00in. .90in.
Xmax (Linear) 8.70mm 7.48mm 8.70mm 7.48mm 8.70mm 7.48mm
.343in. .293in. .343in. .293in. .343in. .293in.
Xmax (Mechanical) 25.4mm 25.4mm 25.4mm 25.4mm 25.4mm 25.4mm
1.0in. 1.0in. 1.0in. 1.0in. 1.0in. 1.0in.
Le 1.5mH 2.5mH 1.5mH 2.5mH 1.5mH 2.5mH
Mms 125.9 g 107.2 g 141.4 g 121.4 g 172.6 g 152.6 g
Driver Weight 3.7kg 3.7kg 3.7kg 3.7kg 3.7kg 3.7kg
8lb.3oz. 8lb.3oz. 8lb.3oz. 8lb.3oz. 8lb.3oz. 8lb.3oz.
Magnet Weight 1.1kg 1.1kg 1.1kg 1.1kg 1.1kg 1.1kg
2.5lb. 2.5lb. 2.5lb. 2.5lb. 2.5lb. 2.5lb.
Vd (Volume of Driver) .022 ft.
3
.022 ft.
3
.042 ft.
3
.042 ft.
3
.062 ft.
3
.062 ft.
3
Driver Cut out Diameter 7.26 7.26 9.30 9.30 11.16 11.16
18.4cm 18.4cm 23.6cm 23.6cm 28.3cm 28.cm
Polk Audio, Inc. warrants the original purchaser only
that this Polk Audio dX Product (the Product) will be
free from defects in materials and workmanship for
a period of (1) one year from the date of original
retail purchase from a Polk Audio Authorized Dealer.
However, this warranty will automatically terminate
prior to the expiration of the (1) one year period if the
original retail purchaser sells or otherwise transfers
the Product to any other party. The original retail
purchaser shall herein after be referred to as “you.”
To allow Polk Audio to offer the best possible warranty
service, please fill out the Product Registration
Card(s) and send them to the Factory at the address
provided in the Registration Card within (10) ten
days of the date of purchase.
Defective Products must be shipped, together with a
proof of purchase, prepaid insured to the Authorized
Polk Audio Dealer from whom you purchased the
Product, or to Polk Audio, 2550 Britannia Blvd.,
Suite D, San Diego,CA 92154. Products must be
shipped in the original shipping container or its
equivalent; in any case the risk of loss or damage
in transit is to be borne by you. If, upon examination
at the Factory or Polk Audio Authorized Dealer it is
determined that the unit was defective in materials
or workmanship at any time during the Warranty
period, Polk Audio or the Polk Audio Dealer will, at its
option, repair or replace this Product at no additional
charge, except as set forth below. All replaced parts
and Products become property of Polk Audio.
Products replaced or repaired under this Warranty
will be returned to you, within a reasonable time,
freight prepaid.
This Warranty does not include service or parts to
repair damage caused by accident, disaster, misuse,
abuse, negligence, inadequate packing or shipping
procedures, commercial use, voltage inputs in excess
of the rated maximum of the unit, cosmetic appearance of the cabinetry not directly attributable to
defects in materials or workmanship, or service,
repair, or modifications of the Product which has
not been authorized or approved by Polk Audio.
This Warranty is in lieu of all other expressed
Warranties. If this Product is defective in materials
and workmanship as warranted above, your sole remedy shall be repair or replacement as provided above.
In no event will Polk Audio, Inc. be liable to you for
any incidental or consequential damages arising out
of the use or inability to use the Product, even if Polk
Audio, Inc. or a Polk Audio Dealer has been advised
of the possibility of such damages, or any other
claim by any other party. Some states do not allow
the exclusion or limitation of consequential damages,
so the above limitation and exclusion may not apply
to you. This Warranty gives you specific legal rights
which may vary from state to state.
This warranty applies only to Products purchased in
the United States of America, its possessions, and U.S.
and NATO armed forces exchanges and audio clubs.
The Warranty terms and conditions applicable to
Products purchased in other countries are available
from the Polk Audio Authorized Distributors in
such countries.
dX Series 1 Year Warranty
5601 Metro Drive • Baltimore, Maryland 21215 • (800) 377-7655
http://www.polkaudio.com
“Polk,” “Polk Audio,” “The Speaker Specialists” and “Dynamic Balance” are registered
trademarks of Polk Investment Corporation used under license by Polk Audio Incorporated.
RM0294-1
CE
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