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Proline X PO 8T-S W EPICX8 sealed wedge enclosure, product photos pending. Placeholder graphic reading Photos Coming Soon.

Performance Optimized · Datasheet

AudioControl EPICX8 Triple Box: Sealed 8" Wedge Enclosure Triple 8" Sealed enclosure

Net volume
0.400 cu ft per driver, 1.20 cu ft total, after both dividers and an estimated 0.038 cu ft displacement per driver
Max mounting depth
4.10 in required; 3.93 in clearance above the motor against the raked rear panel
External dimensions
32 in W × 11 in at the seat face H × 13.54 in at the base D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
AudioControl EPICX8Buy at Audio Intensity
  • Best For: Triple AudioControl EPICX8 Trunk-Fit Builds
  • Net Volume: 0.400 cu ft per Driver (1.20 cu ft Net Total)
  • Driver Match: Three AudioControl EPICX8 (Dual 2 Ohm / Dual 4 Ohm), matched
  • Construction: 3 Chambers | 32" Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | 3 Terminal Cups

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Wedge
Compatible DriverAudioControl EPICX8, quantity 3, matched. Direct fit
ConfigurationTriple 8 inch sealed wedge, 3 chambers, 1 driver per chamber
Mounting PositionTrunk floor, raked face against the rear seat back
Firing DirectionRearward into the trunk. Not a down fire design
External Width32 in
External Height11 in at the seat face
External Depth13.54 in at the base, tapering to 9.53 in at the top
Internal Volume, Gross1.38 cu ft total
Internal Volume, Net Acoustic0.400 cu ft per driver, 1.20 cu ft total, after both dividers and an estimated 0.038 cu ft displacement per driver
Driver Mounting Depth4.10 in required; 3.93 in clearance above the motor against the raked rear panel
Alignment Per DriverEPICX8 D2 Qtc 0.791, fc 59.4 Hz, F3 53.7 Hz; EPICX8 D4 Qtc 0.782, fc 60.0 Hz, F3 54.8 Hz anechoic
Woofer Openings3 at 6.900 in
Woofer LayoutOne row across the face
Frame Outer Diameter8.5 in
Fs / Qts / Qes / Qms47.0 Hz / 0.626 / 0.690 / 6.750
Vas / Sd / Xmax6.7 L / 209 cm2 / 9 mm
Driver Power Handling400 W RMS per driver, 1200 W RMS for the set of 3 (thermal rating)
Recommended Amplifier150-210 W RMS per driver, 450-630 W RMS for the full set
Parameter SourceAudioControl published specifications
MaterialLangboard Elite MDF
ConstructionCNC cut, V-groove and dado joinery
Panel Thickness0.75 in
Front Baffle1.5 in double baffle, outer layer machined as a flush recess
Internal BracingTwo full-height 3/4 in dividers
Driver MountingThreaded insert kit and stainless machine screws included; no bolt circle is published
Terminal CupsThree Proline X ABS and carbon fiber composite, on the rear panel, one per chamber, pre wired 12 gauge OFC
Acrylic InsertGloss black acrylic baffle insert standard
DampingLight polyfill wall lining in every chamber, does not alter acoustic volume
CarpetPlush black
Shipping Weight44 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
0.400
cu ft per driver
System Qtc
0.78–0.79
sealed
Half power
53.7–54.8
Hz · F3
Xmax at
197
W RMS per driver · no filter
With 25 Hz subsonic
213
W RMS per driver · +8%
Amplifier, per driver
150–210
W RMS recommended
This enclosure holds 0.400 cu ft net per driver. In it the AudioControl EPICX8 D2 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 per driver, 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 per driver — +16 W, or 8 percent more power for the same 9.25 mm of travel.

00Sizing the amplifier

Every wattage on this panel is per driver. This cabinet holds three, so the amplifier feeds all three at once.

Per driver 150–210 W RMS  ×  3 drivers  =  full set 450–630 W RMS
Look for a mono amplifier rated 450–630 W RMS at the load your coil version wires to. Travel sets the top here, not heat: past 213 W per driver the cone runs beyond Xmax even with the subsonic set, under the driver’s 400 W thermal rating. The top of the range needs the 25 Hz subsonic filter set; without it, keep each driver under 197 W, where the cone reaches Xmax unfiltered. Below the bottom of the range it will play, just with less headroom; above the top you are buying power the drivers cannot use.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 68.1–68.9
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 Dual 2 Ohm 68.1 Dual 4 Ohm 68.9
Dual 2 Ohm · EBP 68.1Dual 4 Ohm · EBP 68.9
At 68.1–68.9 the EPICX8 D2 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

0.400 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
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
Dual 2 Ohm · Qtc 0.79, Fc 59 Hz, F3 53.7 HzDual 4 Ohm · 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. Figures are AudioControl’s published parameters; Qes and Qms reproduce the printed Qts. This cabinet holds three drivers in three separate sealed chambers of 0.400 cubic feet each, the volume plotted here.

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.

PXmax = 197–202 W per driver unfiltered  →  213–219 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 12 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 9.25 mm 197 W reaches Xmax here
Dual 2 Ohm · 197 W, no filterDual 4 Ohm · 202 W, no filterDual 2 Ohm · 213 W with subsonic at 25 Hz, 24 dB/octDual 4 Ohm · 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 per driver, 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 per driver before hitting the same 9.25 mm. That is 8 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs47.00 / 47.60Hzfree-air resonance
Qts0.626 / 0.620Dual 2 Ohm / Dual 4 Ohm
Vas6.74 / 6.68Lequivalent compliance
Sd209.0cm²effective piston area
Xmax9.25mmone-way linear travel
Pe400Wcontinuous RMS
SPL81.9dB1 W / 1 m, derived from T/S

Driver parameters as published by AudioControl EPICX8 D2 / EPICX8 D4 published specifications. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

Start with the size. 0.400 cubic feet per driver puts the EPICX8 at Qtc 0.791, resonance 59.4 Hz, half power 53.7 Hz anechoic. That is the maker's own recommended sealed size for this driver. Butterworth on these figures wants 0.86, which on this platform means 22.6 in deep at the base. It is a small lift near resonance, 0.2 dB above flat. One box serves every coil version: the Dual 2 Ohm at Qtc 0.791, the Dual 4 Ohm at Qtc 0.782.

Measure the base depth, not the top. This cabinet is 13.54 in deep where it meets the floor, 9.53 at the top, 32 wide and 11 tall. In a trunk the 32 has to clear the opening and the wheel wells, the base depth is measured from the seat back with the seat upright and latched, and the 11 has to clear the rear deck.

All three terminal cups are on the rear panel, and the rear panel is the face that goes against the seat back. Wire all three before the box goes in, with enough slack to slide it into place; once the raked face is against the seat you cannot reach them.

Impedance. EPICX8 D2: wire for 3 ohms (coils in parallel, the three in series), the load most monoblocks are built to deliver full power into; 1.33 ohms is the other clean option (coils in series, the three cups in parallel). EPICX8 D4: wire for 2.67 ohms (coils in series, the three cups in parallel), the load most monoblocks are built to deliver full power into; 6 ohms is the other clean option (coils in parallel, the three in series). Work the load out before you buy the amplifier, not after.

Power. Size the amplifier for the set, not one driver: 150 to 210 W RMS per driver is 450 to 630 W RMS across all 3. On this driver travel sets the top, not heat: Xmax arrives at 213 W per driver with a 25 Hz subsonic, under the 400 W rating. Set the 25 Hz subsonic to use the top of that range; without it keep each driver under 197 W.

AudioControl's Qes and Qms reproduce the printed Qts within 3 percent, so the alignment rests on a self-consistent set. AudioControl do not publish driver displacement; we deduct an estimated 0.038 per driver, so true net can sit a few hundredths either way.

Polyfill is in as a wall lining in every chamber. Do not add more: it makes the box act larger and walks Qtc off 0.79.

Before you order

Questions

Does this fit the AudioControl EPICX8, and its coil versions?

Yes. Each opening is cut to 6.900 in for the 8.5 in frame, and the 4.10 in deep motor clears the raked rear panel with 3.93 in to spare. Both coil versions share the frame, cutout and mounting depth; the alignment table lists each.

Run three matched drivers, same model and same coil, so every chamber sees the alignment on this page.

Why 0.400 cubic feet per driver, and what alignment does it target?

On AudioControl's published Fs 47.0 Hz, Qts 0.626 and Vas 6.7 liters, 0.400 cubic feet per driver gives Qtc 0.791, system resonance 59.4 Hz and half power 53.7 Hz.

The cabinet is built to 0.40 cubic feet per driver, the maker's own recommended sealed size for the AudioControl EPICX8. Maximally flat would need 0.86 cubic feet per driver; this size trades a little low end for a compact box and a small lift near resonance, 0.2 dB above flat.

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

AudioControl rates the EPICX8 at 400 watts RMS per driver. Recommended amplifier: 150 to 210 W RMS per driver, 450 to 630 W RMS for the full set of 3. Travel, not heat, sets the top: the cone reaches Xmax at 213 W per driver with a 25 Hz subsonic set, under the 400 W rating. The top of that range needs the 25 Hz subsonic; without it keep each driver under 197 W.

Each EPICX8 D2 has two 2 ohm voice coils, 4 ohms in series or 1 ohm in parallel. With each driver's coils in series and the three cups in parallel, the three present 1.33 ohms to a mono amplifier. With each driver's coils in parallel and the three in series, they present 3 ohms. Three drivers do not reach the round loads a pair does, so check the result against your amplifier's minimum stable impedance before powering up. Each EPICX8 D4 has two 4 ohm voice coils, 8 ohms in series or 2 ohms in parallel. With each driver's coils in series and the three cups in parallel, the three present 2.67 ohms to a mono amplifier. With each driver's coils in parallel and the three in series, they present 6 ohms. Three drivers do not reach the round loads a pair does, so check the result against your amplifier's minimum stable impedance before powering up.

Will it fit my trunk?

It is 32 inches wide, 11 tall and 13.54 deep at the base, tapering to 9.53 at the top. Measure the trunk opening, the floor depth from the seat back, and the height under the rear deck.

The raked face goes against the seat back and the woofers fire rearward into the trunk.

Why are all three terminal cups on the back?

Each driver has its own sealed chamber, and the center chamber has no side wall to take a cup. Putting all three on the rear panel gives a matching set, one cup per chamber.

Wire them at the amplifier end; there is no cross-chamber wiring inside the cabinet.

What is the expected low-frequency extension?

Anechoic F3 is 53.7 Hz per driver with system resonance at 59.4 Hz.

Those figures exclude cabin gain. The cabin adds real output below about 50 Hz, so in-vehicle response runs deeper than the numbers above.

Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining in every chamber, and the quantity is chosen so it does not change the acoustic volume.

Do not add more. Packing a sealed box makes it behave as though it were larger, which moves the alignment away from 0.400 cubic feet per driver.

Are the drivers included?

No. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, three pre-wired terminal cups on the rear panel, the polyfill lining in place, a threaded insert kit and stainless machine screws.

Bring three matched AudioControl EPICX8 drivers. The cabinet is cut direct fit to them, not a general purpose 8 inch box.

Same series, same size

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