Proline X PO 8-S W EPICX8 sealed wedge, front baffle with gloss black insert and pre-wired leads, 16.6 by 11.8 inches.

Proline X

AudioControl EPICX8 Box: Sealed 8" Wedge Enclosure

Q: Does this fit the AudioControl EPICX8, and will any other 8 inch fit?

The EPICX8, yes, in both coil versions. The baffle is cut to 6.900 in for AudioControl's 8.500 in frame. The 4.10 inch motor clears the cabinet with 0.75 inch to spare.Any other 8, no. The airspace is engineered around the EPICX8's own Qts and Vas, and a different woofer that happened to drop into the hole would not see the alignment printed on this page.

Q: What amplifier power should I run, and how should I wire it?

AudioControl rates the EPICX8 at 400 watts RMS, so target 280 to 400 watts RMS at the final load.AudioControl sells the EPICX8 as EPICX8 D2 (dual 2 ohm) and EPICX8 D4 (dual 4 ohm): the EPICX8 D2 (dual 2 ohm) is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel; the EPICX8 D4 (dual 4 ohm) is two 4 ohm coils, 8 ohms in series or 2 ohms in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm your amplifier's minimum stable impedance first.

Q: Why the wedge angle, and why rear-firing into the trunk?

The seat-side face carries a 20 degree rake that matches the lean of a factory rear seat back, so the cabinet sits flush against it and the cargo space in front stays usable. The baffle is the vertical trunk-lid-side face, so the driver fires rearward into the trunk cavity.The trunk acts as an acoustic extension for the sealed box, and the cabin adds real output below 50 Hz, so in-vehicle response runs deeper than the anechoic 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm) on this page.

Q: Why is the front baffle double-layered?

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A single 3/4 inch panel flexes under the pressure an 8 inch woofer puts on it at 400 watts, which smears output and works the driver loose over time; the second layer stiffens the face and gives the mounting hardware twice the material to bite.The outer layer is machined as a flush recess to AudioControl's 8.500 inch frame, so the driver bolts to the inner layer and sits flush with the gloss black acrylic insert.

Q: What is the expected low-frequency extension?

Anechoic F3 is 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm). Above Qtc 0.707 F3 sits below fc, so the response carries a small lift near resonance before it rolls off.Those figures exclude cabin gain. In a car the cabin's transfer function adds real output below 50 Hz, so in-vehicle response runs deeper than the numbers above.

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 walks the alignment away from the 0.40 cubic feet this cabinet was built to.

Q: Is the driver included, and are the threaded inserts installed?

No driver. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, one side-mounted pre-wired terminal cup, the polyfill lining already in place, and a threaded insert kit with stainless machine screws.The inserts are not pre-installed: AudioControl publishes no bolt circle for the EPICX8, so set the driver in its recess, mark its holes, drill and press the inserts. The AudioControl EPICX8 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 8 inch box.

SKU: PO 8-S W EPICX8 BB

QUICK SPECS

Best For: AudioControl EPICX8 Trunk-Fit Builds
Net Volume: 0.40 cu ft (0.45 cu ft Gross)
Driver Match: AudioControl EPICX8 (EPICX8 D2 (dual 2 ohm) and EPICX8 D4 (dual 4 ohm))
Construction: Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Insert Kit

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.

$ 269.99

Acrylic Insert Color

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

AudioControl EPICX8 Box: Sealed 8" Wedge Enclosure

Enclosure Type Sealed

External Dimensions 16.63" W x 11.75" H x 10.47" D at base tapering to 6.19" D at top

Gross Volume 0.45 cu ft

Net Volume 0.40 cu ft

Shipping Weight 24 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

0.40 cubic feet: Qtc 0.791 on the EPICX8 D2 (dual 2 ohm) and Qtc 0.782 on the EPICX8 D4 (dual 4 ohm), F3 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm).

The 4.10 inch motor clears the raked back with 0.75 to spare; the airspace sets the rest of the cabinet.

AudioControl's EPICX table is consistent between its coils but loose inside each column, and they do not give displacement, so that one is estimated. The alignment is built to their own recommended box.

No bolt circle is published, so the insert kit ships in the box: mark, drill and press at install. Sealed, so leave the polyfill as it is and run it at 400 watts or under per driver.

Product Details

Performance Optimized Wedge | AudioControl EPICX8

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

0.40 ft3 Net0.45 ft3 GrossQtc 0.78 to 0.79Single Chamber Wedge16.63" x 11.75" x 6.19/10.47"Built in Tennessee

The AudioControl EPICX8 in a Sealed Wedge

The EPICX8 is AudioControl's 8 inch EPICX: a non-pressed paper cone, a composite foam surround, a rigid steel basket, a high-temperature lightweight voice coil and a one-piece dust cap, rated 400 watts RMS with 9.25 mm of one-way excursion, 4.10 inches of mounting depth on an 8.50 inch frame. Every Thiele-Small figure comes from AudioControl's own EPICX8 user manual. Both coil columns agree on Vas and resonance, and both reproduce their printed Qts; the D2 column is measured with the coils in series and the D4 in parallel, which is why their Re and Bl differ while their Re over Bl squared does not.

0.40 cubic feet net on AudioControl's published figures: the EPICX8 D2 (dual 2 ohm) reads Qtc 0.791 with resonance at 59.4 Hz and half power at 53.7 Hz, and the EPICX8 D4 (dual 4 ohm) reads Qtc 0.782 with resonance at 60.0 Hz and half power at 54.8 Hz. One cabinet serves both coils. That is AudioControl's own recommended sealed size for this driver, 0.4 cubic feet, between their 0.25 minimum and 0.65 maximum. That is a touch above maximally flat: a small lift near resonance and firm midbass.

Trunk-Load Wedge Design Explained

The driver 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 AudioControl EPICX8

Anechoic half power lands at 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm), before any cabin gain. AudioControl does not publish driver displacement for the EPICX, so an estimated 0.038 cubic feet per driver is taken out of the net figure.

Alignment Numbers

Driver	System Qtc	fc	F3
EPICX8 EPICX8 D2 (dual 2 ohm)	Qtc 0.791	59.4 Hz	53.7 Hz
EPICX8 EPICX8 D4 (dual 4 ohm)	Qtc 0.782	60.0 Hz	54.8 Hz

Mounting Geometry

The baffle is cut to 6.900 in for AudioControl's 8.500 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 6.19 in at the top to 10.47 in at the base, and the 4.10 in motor clears it with 0.75 in to spare. AudioControl prints no bolt circle for the EPICX8, so the baffle ships undrilled with a threaded insert kit and stainless machine screws: set the driver in its recess, mark its holes, drill and press the inserts.

What the Numbers Rest On

Langboard Elite MDF

Premium 3/4 in MDF throughout.

V-Groove and Dado Joinery

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

Double-Layer 1.5" Front Baffle

Two bonded 3/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.

AudioControl's Published Parameters

EPICX8 D2 (dual 2 ohm): Fs 47 Hz, Qts 0.626, Qes 0.69, Qms 6.75, Vas 6.74 L, Mms 93.66 g, Bl 12.79 N/A, Re 3.8 ohm. EPICX8 D4 (dual 4 ohm): Fs 47.6 Hz, Qts 0.62, Qes 0.691, Qms 6.02, Vas 6.68 L, Mms 86.46 g, Bl 8.15 N/A, Re 1.6 ohm. Cone area 209 cm2. Xmax 9.25 mm (one-way, method not stated).

Wiring the AudioControl EPICX8 to Your Amplifier

AudioControl sells the EPICX8 as EPICX8 D2 (dual 2 ohm) and EPICX8 D4 (dual 4 ohm): the EPICX8 D2 (dual 2 ohm) is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel; the EPICX8 D4 (dual 4 ohm) is two 4 ohm coils, 8 ohms in series or 2 ohms in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm the final load against your amplifier's minimum stable impedance before powering the system.

Power handling is 400 watts RMS per driver. Aim for roughly 280 to 400 watts at the impedance you wire.

Built in Tennessee, Backed by Audio Intensity

Cut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one pre-wired terminal cup, 12 gauge OFC to the driver position. Polyfill wall lining installed. Threaded insert kit and stainless machine screws included (AudioControl publishes no bolt circle). 1 year limited warranty. Enclosure only, the driver is purchased separately. Call or text 931-563-5151.

AudioControl EPICX8: Cut for One Driver

0.40 cubic feet net at Qtc 0.78 to 0.79, F3 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm), cut direct fit and built to order in Tennessee.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	AudioControl EPICX8 (EPICX8 D2 (dual 2 ohm) and EPICX8 D4 (dual 4 ohm)), quantity 1. Direct fit
Configuration	Single 8 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	16.63 in
External Height	11.75 in at the seat face
External Depth	10.47 in at the base, tapering to 6.19 in at the top
Internal Volume, Gross	0.45 cu ft
Internal Volume, Net Acoustic	0.40 cu ft after the brace and the driver displacement
Driver Mounting Depth	4.10 in required; 0.75 in clearance above the motor against the raked rear panel
Alignment, EPICX8 D2 (dual 2 ohm)	Qtc 0.791, fc 59.4 Hz, F3 53.7 Hz anechoic
Alignment, EPICX8 D4 (dual 4 ohm)	Qtc 0.782, fc 60.0 Hz, F3 54.8 Hz anechoic
Woofer Opening	6.900 in, cut for AudioControl's frame
Frame Outer Diameter	8.500 in
Bolt Circle	Not published by AudioControl; threaded insert kit included
Driver Displacement	0.038 cu ft, estimated; AudioControl publishes none for the EPICX
EPICX8 D2 (dual 2 ohm) Fs / Qts / Qes / Qms / Vas	47 Hz / 0.626 / 0.69 / 6.75 / 6.74 L
EPICX8 D4 (dual 4 ohm) Fs / Qts / Qes / Qms / Vas	47.6 Hz / 0.62 / 0.691 / 6.02 / 6.68 L
Driver Sd	209 cm2, AudioControl spec
Xmax	9.25 mm, one-way, method not stated
Driver Power Handling	400 W RMS
Wiring Options	AudioControl sells the EPICX8 as EPICX8 D2 (dual 2 ohm) and EPICX8 D4 (dual 4 ohm): the EPICX8 D2 (dual 2 ohm) is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel; the EPICX8 D4 (dual 4 ohm) is two 4 ohm coils, 8 ohms in series or 2 ohms in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it.
Parameter Source	AudioControl EPICX8 user manual
Material	Langboard Elite MDF
Construction	CNC cut, V-groove and dado joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in double baffle, outer layer machined as a flush recess
Internal Bracing	Windowed brace, dadoed to the shell
Driver Mounting	Threaded insert kit and stainless machine screws included; inserts set at install, no bolt circle is published
Terminal Cups	One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
Acrylic Insert	Gloss black acrylic baffle insert standard; None variant minus $20
Damping	Light polyfill wall lining, does not alter acoustic volume
Carpet	Plush black
Shipping Weight	24 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

0.40

cu ft

System Qtc

0.78–0.79

sealed

Half power

53.7–54.8

Hz · F3

Xmax at

197

W RMS · no filter

With 25 Hz subsonic

213

W RMS · +8%

Amplifier

400

W RMS recommended

This enclosure holds 0.40 cu ft net . In it the AudioControl EPICX8 runs a system Qtc of 0.78–0.79 with half power at 53.7–54.8 Hz, and the cone reaches its 9.25 mm travel limit at 197 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 213 W — +16 W, or 8 percent more power for the same 9.25 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 68.1–68.9

EPICX8 D2 · EBP 68.1EPICX8 D4 · EBP 68.9

At 68.1–68.9 the EPICX8 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

0.40 cu ft against a 6.7 L Vas.

α = Vas ÷ Vb = 0.60 · Fc = Fs√(α+1) = 59–60 Hz · Qtc = 0.78–0.79

EPICX8 D2 · Qtc 0.79, Fc 59 Hz, F3 53.7 HzEPICX8 D4 · Qtc 0.78, Fc 60 Hz, F3 54.8 Hz

The box lifts resonance from 47.0–47.6 Hz free-air to 59–60 Hz and half power lands at 53.7–54.8 Hz, anechoic, before any cabin gain. Parameters are AudioControl’s own user manual for each coil plotted; driver displacement is not published for the EPICX and is estimated. Only the coils this listing carries are plotted; the other version falls outside a well-behaved sealed alignment in this cabinet.

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 9.25 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

P_Xmax = 197–202 W unfiltered → 213–219 W with a 25 Hz subsonic

EPICX8 D2 · 197 W, no filterEPICX8 D4 · 202 W, no filterEPICX8 D2 · 213 W with subsonic at 25 Hz, 24 dB/octEPICX8 D4 · 219 W with subsonic at 25 Hz, 24 dB/octXmax 9.25 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 9.25 mm. Unfiltered that is 197 W, reached first at 27 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 213 W before hitting the same 9.25 mm. That is 8 percent more amplifier for the price of one filter setting.

Param	Value	Unit	Note
Fs	47.00 / 47.60	Hz	free-air resonance
Qts	0.626 / 0.620		EPICX8 D2 / EPICX8 D4
Vas	6.74 / 6.68	L	equivalent compliance
Sd	209.0	cm²	effective piston area
Xmax	9.25	mm	one-way, method not stated
Pe	400	W	continuous RMS
SPL	81.9	dB	1 W / 1 m, derived from T/S

Driver parameters as published by AudioControl user manual. Curves computed against this enclosure’s actual net airspace.

Customer Installs

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.