Proline X

Performance Optimized Wedge Sealed 12" Enclosure | PowerBass XL-1244

Q: Will this enclosure fit the XL-1244 exactly?

Yes. The baffle is CNC cut to 11.0625 in for the XL-1244's published cutout and the cabinet clears its 5.7500 in mounting depth. Threaded inserts are pressed in at every mounting location so the driver bolts to metal, not to MDF.

Q: Why 1.25 cubic feet net?

It is PowerBass's published sealed recommendation for the XL-1244. In it the driver runs Qtc 0.714 with fc at 46.6 Hz and F3 at 46.2 Hz. PowerBass publishes Qtc 0.850 and F3 44 Hz for the same airspace, so our numbers and theirs agree.

Q: What amplifier power should I run, and what impedance?

The XL-1244 is rated 400 watts RMS, so 400 across the driver. This is a single 4 ohm voice coil, so one driver is simply a 4 ohm load. There is no series or parallel decision to make. Aim for roughly 280 to 400 watts at the final wired impedance.

Q: How does a wedge enclosure improve the sound in a trunk installation?

The angled seat-side face matches the roughly 20 degree lean of a factory rear seat, so the cabinet sits flat against it instead of leaving a wasted triangle. The vertical trunk-lid-side face carries the driver, firing rearward into the trunk cavity, which acts as an acoustic extension into the cabin.

Q: Why is the front baffle double-layered?

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A subwoofer pushes as hard against its mounting surface as it does against the air, and a single 3/4 inch panel flexes under that load. With 8 mm of one-way travel and 400 watts on tap that matters.

Q: What is the expected low-frequency extension?

F3 lands at 46.2 Hz anechoic, before any cabin gain. Qtc is 0.714, so the rolloff is clean rather than peaked. These figures are anechoic and exclude cabin gain, which in most vehicles adds real output below 40 Hz.

Q: Do I need to add polyfill or damping?

No. Polyfill is already installed 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 on this driver moves Qtc down and F3 up.

Q: Is the driver included?

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

SKU: PO 12-S W XL1244 BB

QUICK SPECS

Best For: PowerBass XL-1244 Trunk-Fit Builds
Net Volume: 1.25 cu ft (1.38 cu ft Gross)
Alignment: Qtc 0.714, fc 46.6 Hz, F3 46.2 Hz
Driver Match: XL-1244
Impedance: single 4 ohm coil
Construction: Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Inserts

Shipping Included No freight charges at checkout. What you see is what you pay.

Built in Tennessee CNC cut from 3/4" Langboard Elite MDF. V-groove and dado joinery.

Advanced Terminal Cup Built in-house. ABS/Carbon Fiber. Stainless steel hardware. Copper ring terminals.

$ 299.99

Acrylic Insert Color

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Performance Optimized Wedge Sealed 12" Enclosure | PowerBass XL-1244

Enclosure Type Sealed

External Dimensions 28.06" W x 15" H x 12.65" D at base tapering to 7.19" D at top

Net Volume 1.25cu ft

Tuning Frequency N/A (Sealed)

Cutout Diameter Direct Fit

Front Panel Thickness 1.5"

Max Mounting Depth Direct Fit

INSTALLER'S TAKE

This one is straightforward. 1.25 cubic feet net is PowerBass's own published sealed airspace for the XL-1244 and we cut to it exactly, which lands at Qtc 0.714. PowerBass publishes 0.850 at the same volume, so there is no argument to have about the alignment.

F3 lands at 46.2 Hz anechoic, before any cabin gain.

On impedance: This is a single 4 ohm voice coil, so one driver is simply a 4 ohm load. There is no series or parallel decision to make.

Measure the base depth. This cabinet is 12.65 inches deep at the trunk floor, 7.19 at the top, and 28.06 wide. The floor dimension is what decides whether it goes in.

Product Details

Performance Optimized Wedge | PowerBass XL-1244

12" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design

1.25 ft3 Net1.38 ft3 GrossQtc 0.71Rear-Firing Wedge28.06" x 15" x 7.19/12.65"Built in Tennessee

The PowerBass XL-1244 in a Sealed Wedge

A 2 inch vented BASV voice coil with Aero-Vent perimeter cooling, a DDC coated non-pressed paper cone, dual stack magnets and a 400 watt RMS rating. The alignment below is computed from PowerBass's own published Thiele-Small parameters.

1.25 cubic feet net is PowerBass's published sealed recommendation for the XL-1244, and this cabinet is cut to it exactly. Gross is 1.38 cu ft before the driver's 0.1210 cu ft displacement.

Trunk-Load Wedge Design Explained

The XL-1244 mounts on the vertical trunk-lid-side face and fires rearward into the trunk cavity.

Seat-Side Face Matches Seat Lean

Angled face matches the roughly 20 degree factory seat lean.

Trunk-Lid-Side Face Fires the Woofer

Vertical baffle, cone firing rearward into the trunk cavity.

Trunk Cavity Loading

The trunk acts as an acoustic extension for a smoother presentation.

Preserves Trunk Cargo Space

The wedge tucks against the seat back and the space in front stays usable.

Engineered for the PowerBass XL-1244

At 1.25 cubic feet net the XL-1244 runs a system Qtc of 0.714, essentially a textbook Butterworth alignment. PowerBass publishes 0.850 for this driver at the same airspace, so the cabinet and the maker agree.

F3 lands at 46.2 Hz anechoic, before any cabin gain.

Alignment Numbers

Qtc 0.714 · fc 46.6 Hz · F3 46.2 Hz anechoic · Qts 0.421, Vas 66.37 L, Fs 27.5 Hz as published

Mounting Geometry

Vertical baffle CNC cut to 11.0625 in. Driver mounting depth 5.7500 in required. Threaded inserts pressed into the baffle backside at every mounting location.

Performance Series Construction, Driver-Specific Tuning

Langboard Elite MDF

Premium 3/4 in MDF throughout.

V-Groove and Dado Joinery

CNC cut V-grooves at every panel intersection, sides seated in dados.

Double-Layer 1.5" Front Baffle

Two bonded 3/4 in MDF sheets at the driver face.

Pre-Wired Terminal Cup

Proline X ABS and carbon fiber composite, 12 gauge OFC pre-wired to the driver position.

Wiring the PowerBass XL-1244 to Your Amplifier

This is a single 4 ohm voice coil, so one driver is simply a 4 ohm load. There is no series or parallel decision to make.

Power handling is 400 watts RMS. Aim for roughly 280 to 400 watts at the final wired impedance.

Built in Tennessee, Backed by Audio Intensity

Cut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet. 1 year limited warranty. Enclosure only, the PowerBass XL-1244 driver is purchased separately. Call or text 931-563-5151.

PowerBass XL-1244: Cut to PowerBass's Own Airspace

1.25 cubic feet net at Qtc 0.71, F3 46.2 Hz, built to order in Tennessee.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	PowerBass XL-1244, quantity 1. Direct fit
Configuration	Single 12 inch, single chamber sealed wedge
Mounting Position	Trunk or cargo area, tall face against the rear seat back
Firing Direction	Rearward into the trunk. Not a down fire design, no feet included
External Width	28.06 in
External Height	15 in at the seat face
External Depth	12.65 in at the base, tapering to 7.19 in at the top
Internal Volume, Gross	1.38 cu ft
Internal Volume, Net Acoustic	1.25 cu ft
Alignment	Qtc 0.714, fc 46.6 Hz, F3 46.2 Hz anechoic
Driver Cutout	11.0625 in
Driver Mounting Depth	5.7500 in required
Power Handling	400 watts RMS
Impedance	Single 4 ohm voice coil
Material	Langboard Elite MDF
Construction	CNC cut, V-groove and dado joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in, double baffle
Internal Bracing	Windowed C brace
Driver Mounting	Threaded inserts at every mounting location, stainless machine screws included
Terminal Cups	One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
Damping	Light polyfill wall lining, does not alter acoustic volume
Carpet	Plush black
Weight	39.4 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

1.25

cu ft per chamber

System Qtc

0.71

sealed

Half power

46.2

Hz · F3

Xmax at

112

W RMS · no filter

With 25 Hz subsonic

150

W RMS · +33%

Amplifier

400

W RMS recommended

This enclosure holds 1.25 cu ft net per chamber. In it the PowerBass XL-1244 runs a system Qtc of 0.71 with half power at 46.2 Hz, and the cone reaches its 8.0 mm travel limit at 112 W, below the driver’s 400 W thermal rating, so travel is what stops you here, not heat. Run a subsonic filter at 25 Hz and that becomes 150 W — +37 W, or 33 percent more power for the same 8.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 59.5

XL-1244 · EBP 59.5

At 59.5 the XL-1244 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

1.25 cu ft against a 66.4 L Vas.

α = Vas ÷ Vb = 1.88 · Fc = Fs√(α+1) = 47 Hz · Qtc = 0.71

XL-1244 · Qtc 0.71, Fc 47 Hz, F3 46.2 Hz

The box lifts resonance from 27.5 Hz free-air to 47 Hz and half power lands at 46.2 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 8.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

P_Xmax = 112 W unfiltered → 150 W with a 25 Hz subsonic

XL-1244 · 112 W, no filterXL-1244 · 150 W with subsonic at 25 Hz, 24 dB/octXmax 8.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 8.0 mm. Unfiltered that is 112 W, reached first at 20 Hz. It sits under the 400 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: stopping the cone wasting travel below the passband lets it take 150 W before hitting the same 8.0 mm. That is 33 percent more amplifier for the price of one filter setting.

Param	Value	Unit	Note
Fs	27.50	Hz	free-air resonance
Qts	0.421		XL-1244
Vas	66.37	L	equivalent compliance
Sd	490.9	cm²	effective piston area
Xmax	8	mm	one-way linear travel
Pe	400	W	continuous RMS
SPL	86.6	dB	1 W / 1 m, derived from T/S

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

Materials

Material

Built From a Spec Sheet, Not a Sales Sheet

Every Proline X Performance Series enclosure is CNC-cut from Langboard Elite MDF, 3/4" (18mm) panels produced to published mill specifications. Most enclosure manufacturers source generic MDF without published data. We can tell you the internal bond rating, the modulus of elasticity, the modulus of rupture, and the face and edge screw holding strength for every panel in this enclosure, because we chose the material based on those numbers, not on price or availability.

Langboard Elite is produced in the United States. The specifications below are pulled directly from Langboard's published mill data and are verifiable. This is the same panel stock used in our full Proline X lineup.

Specifications

Langboard Elite MDF: Published Mill Data

Property	Value	Why It Matters
Panel Stock	Langboard Elite MDF	Named, verifiable panel source, not generic "high-density MDF"
Thickness	3/4" (18mm)	Industry standard for subwoofer enclosures; panels below this flex under pressure
Density	48.5 lbs/ft³	Higher density = less porosity, better screw retention, reduced resonance
Internal Bond	200 psi	Measures resistance to delamination under sustained internal pressure. The most enclosure-relevant spec on this sheet
Modulus of Rupture (MOR)	4,200 psi	Bending strength before the panel breaks, relevant for larger unsupported baffle spans
Modulus of Elasticity (MOE)	410,000 psi	Stiffness under load; higher MOE means less panel flex under bass pressure, less resonance
Face Screw Holding	325 lbs	How firmly the panel surface holds a screw; critical for baffle joint integrity over time
Edge Screw Holding	250 lbs	Panel edge retention, relevant for every joint that isn't face-to-face

Internal Bond

200 psi: The Number That Actually Matters for Enclosures

The internal bond rating measures how well the MDF panel resists delamination under sustained pressure applied perpendicular to the face. In a subwoofer enclosure, every bass transient generates a pressure pulse that pushes outward on every panel simultaneously. A panel that begins to delaminate internally loses stiffness gradually. The symptoms are slow: a box that starts to sound softer, less defined, less punchy over months of use. 200 psi internal bond is the spec that determines how long this enclosure holds its acoustic integrity under daily use at real power levels.

Stiffness

410,000 psi MOE: Less Flex, Less Resonance

The modulus of elasticity measures panel stiffness, its resistance to bending under load. A stiffer panel flexes less under the pressure generated by a high-excursion driver at volume. Panel flex is a source of acoustic coloration: the panel itself begins to radiate sound at its own resonant frequency, adding distortion to the output. 410,000 psi stiffness combined with V-groove and dado joinery means the panels stay rigid and the bracing controls resonance at the structure level, not the panel level. The bass you hear comes from the driver, not the box.

Screw Holding

325 lb Face / 250 lb Edge: Joints That Stay Locked

Screw holding strength determines how firmly the panel grips a fastener at the face and at the edge. This matters most at the baffle joint, where the front panel meets the side panels and where the driver is mounted. A panel with low screw holding strength allows fasteners to loosen over time under vibration, leading to air gaps at the joint and loss of acoustic seal. 325 lb face screw holding strength means the baffle hardware stays put. Combined with dado joinery and adhesive, the front panel on a Proline X Performance Series enclosure is not going anywhere.

Sourcing

Named Panel Stock: Not "Premium MDF"

The phrase "premium MDF" or "high-density MDF" appears on marketing copy for enclosures across every price point, from $40 to $400. It is not a specification. It is a description with no defined standard. Langboard Elite is a named, sourced, mill-documented product with published data. We name it in our copy because naming it holds us accountable to the spec. You can look up Langboard Elite independently, verify the numbers on this page, and confirm you are getting what we say you are getting. That is the point.

Why Proline X?

Most enclosures are built to a price point. Proline X is built to a spec. Every box starts with published-data MDF, gets CNC-cut to exact internal volume, and is assembled by hand in our Tennessee facility. The difference shows up in the measurements, and in how the box holds up two years into daily use.

CNC-Cut to Spec

Panels are machine-cut on ShopSabre CNC routers and joined with V-groove and dado joinery. Consistent geometry, no hand-cut variance, no gaps at the joints.