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Proline X PO 10D-S DFW XLT sealed down-fire wide enclosure for two PowerBass XL-1040T, 41 inches wide by 5.5625 inches tall, feet add 1.75 inches of height.
Proline X PO 10D-S DFW XLT sealed down-fire wide enclosure, end panel with side-mounted terminal cup, 5.5625 inches tall by 12 inches deep.

Performance Optimized · Datasheet

Performance Optimized Down Fire Wide Sealed Dual 10" Enclosure PowerBass XL-1040T · Dual 10" Sealed enclosure

Net volume
0.606 cu ft total, 0.303 per driver after 0.0771 displacement each
Max mounting depth
3.4 in required, shallow mount
External dimensions
41 in W × 5.5625 in in the down fire position H × 12 in D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
PowerBass XL-1040TBuy at Audio Intensity
  • Alignment: 0.303 cu ft net per driver. Qtc 0.905, Fc 65.0 Hz, F3 53.8 Hz
  • Down Fire Wide: 41"W x 12"D x 5.5625"H, 3" shallower than the standard 30 x 15 cabinet, for under rear seats
  • Driver: PowerBass XL-1040T, 350 W RMS, 7.5 mm Xmax, 3.4 in mounting depth, single 4 ohm
  • Rear Venting: Vented rear motor, pole vent may be fully obstructed
  • Standoffs: Included, 1.75 in, uninstalled. Installed height 7.3125 in

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Down Fire Wide
Compatible DriverPowerBass XL-1040T, quantity 2. Direct fit
ConfigurationDual 10 inch shallow mount, sealed down fire wide, dual chamber
Mounting PositionUnder a rear seat or on a narrow cargo floor where depth is limited, baffle facing down on standoffs
Firing DirectionDownward. Feet ship uninstalled, so front or up firing is also possible
External Width41 in
External Depth12 in
External Height5.5625 in in the down fire position, excludes standoffs
Installed Height7.3125 in including the 1.75 in standoff
Internal Volume, Gross0.775 cu ft total
Internal Volume, Net Acoustic0.606 cu ft total, 0.303 per driver after 0.0771 displacement each
PowerBass Published Target0.30 cu ft optimum, 0.25 to 0.75 acceptable. Their figures are GROSS and include driver displacement
AlignmentQtc 0.905, Fc 65.0 Hz, F3 53.8 Hz anechoic
Comparison, Standard Down Fire30 x 15 x 5.86 in, 0.30 cu ft net per driver. Same airspace, deeper footprint
Woofer Opening9.3125 in (237 mm) direct fit, both positions
Driver Mounting Depth3.4 in required, shallow mount
Driver MotorRear vented, pole vent may be fully obstructed. 1.41 in clearance above the motor
Driver Power Handling350 W RMS, 700 W peak each
Driver Voice CoilSingle 4 ohm, 2 in
Wiring2 ohms parallel or 8 ohms series
MaterialLangboard Elite MDF
ConstructionCNC cut, V-groove and dado joinery, square corners
Panel Thickness0.75 in
Front Baffle1.5 in double baffle, outer layer machined as a flush recess
Internal BracingFull chamber divider
Driver MountingThreaded inserts, stainless machine screws included
Terminal CupsOne Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
StandoffsIncluded, 1.75 in, shipped uninstalled
DampingLight polyfill wall lining, does not alter acoustic volume
CarpetPlush black
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
0.303
cu ft per chamber
System Qtc
0.90
sealed
Half power
53.8
Hz · F3
Xmax at
294
W RMS · no filter
With 25 Hz subsonic
299
W RMS · +2%
Amplifier
350
W RMS recommended
This enclosure holds 0.303 cu ft net per chamber. In it the PowerBass XL-1040T runs a system Qtc of 0.90 with half power at 53.8 Hz, and the cone reaches its 7.5 mm travel limit at 294 W, below the driver’s 350 W thermal rating, so travel is what stops you here, not heat. A 25 Hz subsonic filter adds little here: 299 W against 294 W, 2 percent. The box already resonates at 65 Hz, so its own rolloff has removed most of what the filter would have stopped.

01Is it a sealed driver?

Efficiency bandwidth product places the motor before anything else is decided.

EBP = Fs ÷ Qes = 60.7
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 XL-1040T 60.7
XL-1040T · EBP 60.7
At 60.7 the XL-1040T sits in the transition band, not the sealed band. That is not a mismatch: a transition motor works in either alignment, and sealed buys a smaller box and a gentler roll-off at the cost of some low-end output. Stage 02 shows what this airspace actually does with it.

02What the box does to it

0.303 cu ft against a 21.0 L Vas.

α = Vas ÷ Vb = 2.45  ·  Fc = Fs√(α+1) = 65 Hz  ·  Qtc = 0.90
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
XL-1040T · Qtc 0.90, Fc 65 Hz, F3 53.8 Hz
The box lifts resonance from 35.0 Hz free-air to 65 Hz and half power lands at 53.8 Hz, anechoic, before any cabin gain.

03The watts that reach Xmax (in this enclosure)

Travel scales with the square root of power, so there is one wattage that puts the cone exactly on 7.5 mm, and in this alignment a subsonic filter barely moves it.

PXmax = 294 W unfiltered  →  299 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 7.5 mm 294 W reaches Xmax here
XL-1040T · 294 W, no filterXL-1040T · 299 W with subsonic at 25 Hz, 24 dB/octXmax 7.5 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 7.5 mm. Unfiltered that is 294 W, reached first at 40 Hz. It sits under the 350 W the driver can take thermally, so the enclosure sets the ceiling, not the voice coil. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct, and they sit almost on top of the solid ones: 299 W against 294 W. At 65 Hz the filter sits well below resonance, where the sealed alignment has already rolled the cone off at 12 dB/oct, so there is little wasted travel left for it to recover. Set it anyway to keep road rumble out of the cone, but do not size the amplifier around it.
ParamValueUnitNote
Fs35.00Hzfree-air resonance
Qts0.487XL-1040T
Vas21.02Lequivalent compliance
Sd346.4cm²effective piston area
Xmax7.5mmone-way linear travel
Pe350Wcontinuous RMS
SPL83.8dB1 W / 1 m, derived from T/S

Driver parameters as published by powerbassusa.com. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

Watch the volume convention on this brand. PowerBass quotes 0.30 and that is GROSS, displacement included. This cabinet is 0.303 NET per driver. If a customer says the box looks big against the sheet, that is why, and it is inside their 0.25 to 0.75 acceptable range.

This is the dual for 12 inches of depth under a rear bench. Airspace set the height, 5.5625 inches, the same air per driver as the standard 30 by 15 dual. The motors clear the lid by 1.41, and the vent can be blocked anyway.

Measure the installed height, not the cabinet height. 5.5625 tall plus 1.75 of standoff puts you at 7.3125 inches of stack. Footprint is 41 by 12.

Single 4 ohm coil. A pair gives 2 ohms parallel or 8 ohms series. Nothing to get wrong.

Qtc 0.905, Fc 65.0 Hz, F3 53.8 Hz at 0.303 net. This is a shallow driver in a small box and it reads that way: tight rather than deep. Set the expectation before the sale.

Before you order

Questions

Why is this dual cabinet 41 inches wide instead of 30?

Because it is only 12 inches deep. Our standard Performance Optimized Down Fire cabinet for this driver is 30 wide by 15 deep, and this one is built for spaces three inches shallower than that, typically under the rear seat of a truck or SUV or on a narrow cargo floor.

Airspace has to come from somewhere. Losing depth means recovering it along the length, so the cabinet runs 41 inches long and stands 5.5625 inches tall, and still keeps each driver in a properly sized separate chamber. If your space is wide and shallow rather than deep, this is the shape that works.

How does this compare to the standard 30 x 15 PowerBass XL-1040T enclosure?

Same driver, different shape. The standard cabinet is 30 by 15 by 5.86 inches and holds 0.30 cubic feet net per driver. This cabinet is 41 by 12 by 5.5625 inches and holds 0.303 cubic feet net per driver.

That is effectively the same airspace, so acoustically the two are interchangeable. Choose on the space: with 15 inches of depth the standard cabinet is the pick; if depth stops at 12 inches and you have 41 inches of run, this one fits.

Will this enclosure fit any 10 inch subwoofer?

No. The baffle is cut direct fit at 237 mm for the PowerBass XL-1040T and the airspace is built to that driver; a conventional 10 needs both a deeper cabinet and more air.

Even where another driver dropped into the hole, it would be loading into an airspace engineered around a Qts of 0.487, and the alignment printed on this page would no longer describe what you own.

PowerBass says 0.30 cubic feet. How does this cabinet compare?

PowerBass quotes 0.30 as internal airspace that INCLUDES the driver's displacement, so their figure is gross. We publish net everywhere, meaning the air the cone actually loads against after the driver's 0.0771 cubic feet is taken out.

Each chamber here holds 0.303 cubic feet net, slightly on the larger side of their optimum and comfortably inside the 0.25 to 0.75 range they list as acceptable. That gives Qtc 0.905, Fc 65.0 Hz, F3 53.8 Hz anechoic per driver.

What amplifier power and impedance?

The XL-1040T is rated 350 watts RMS and 700 peak, with a single 4 ohm voice coil. A matched pair gives 2 ohms in parallel or 8 ohms in series, so there is no low impedance trap to fall into on this driver.

Target 700 watts RMS across the pair and set gains properly rather than to a number.

Does the pole vent need clearance under the cabinet?

No. The XL-T uses a vented rear motor, so the pole vent can be obstructed without harming the driver, and this cabinet still clears 1.41 inches above the motor.

The standoffs are there to give the cone room to breathe in front of the baffle, which faces the floor, not to relieve the pole vent. Installed on the 1.75 inch standoffs the finished stack is 7.3125 inches.

Do I need to add polyfill or damping?

No. Polyfill is already installed in both chambers as a light wall lining to control internal reflections, and the quantity is chosen so it does not change the acoustic volume. Do not add more. Packing a sealed box with fill makes it behave as though it were larger, which walks the alignment away from the 0.303 cubic feet per chamber this cabinet was built to. PowerBass also warns against letting fill reach the vented pole piece.

Are the PowerBass XL-1040T included?

No. This is an enclosure only: you receive the cabinet finished in plush black carpet, with threaded inserts at both driver positions, stainless machine screws, one side-mounted pre-wired terminal cup, the standoffs and the polyfill lining already in place.

The drivers are purchased separately. We do not stock PowerBass drivers.

Same series, same size

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