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Proline X PO 12-S DF EPICX12 sealed down fire enclosure, front panel on 1.75 inch feet, 30 by 8.6 inches.
Proline X PO 12-S DF EPICX12 sealed down fire enclosure, end panel with recessed terminal cup, 15 by 8.6 inches.

Performance Optimized · Datasheet

AudioControl EPICX12 Box: Sealed 12" Down Fire Enclosure Single 12" Sealed enclosure

Net volume
1.25 cu ft after the brace and the driver displacement
Max mounting depth
6.00 in required, 1.80 in clearance above the motor
External dimensions
30.00 in W × 8.55 in in the down fire position H × 15.00 in D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
AudioControl EPICX12Buy at Audio Intensity
  • Alignment: 1.25 cu ft net, Qtc 0.89 to 0.98, F3 40.7 Hz on the EPICX12 D2 (dual 2 ohm) and 39.6 Hz on the EPICX12 D4 (dual 4 ohm)
  • Driver: AudioControl EPICX12 (EPICX12 D2 (dual 2 ohm) and EPICX12 D4 (dual 4 ohm)), 500 W RMS, 8.5 mm Xmax, 6.00 in mounting depth
  • Standoffs: Included, 1.75 in, shipped uninstalled. Installed height near 10.30 in
  • Cabinet: 30.00"W x 15.00"D x 8.55"H in down fire position, excludes standoffs, square corners

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Down Fire
Compatible DriverAudioControl EPICX12 (EPICX12 D2 (dual 2 ohm) and EPICX12 D4 (dual 4 ohm)), quantity 1. Direct fit
ConfigurationSingle 12 inch, sealed down fire
Mounting PositionTrunk or cargo floor, baffle facing down on standoffs
Firing DirectionDownward. Feet ship uninstalled, so front or up firing is also possible
External Width30.00 in
External Depth15.00 in
External Height8.55 in in the down fire position, excludes standoffs
Installed Height10.30 in including the 1.75 in standoff
Internal Volume, Gross1.35 cu ft
Internal Volume, Net Acoustic1.25 cu ft after the brace and the driver displacement
Height Set ByAirspace; clearance alone would allow a lower cabinet
Driver Mounting Depth6.00 in required, 1.80 in clearance above the motor
Floor Slot0.76 times the cone area at the 1.75 in standoff
Alignment, EPICX12 D2 (dual 2 ohm)Qtc 0.894, fc 48.9 Hz, F3 40.7 Hz anechoic
Alignment, EPICX12 D4 (dual 4 ohm)Qtc 0.976, fc 49.8 Hz, F3 39.6 Hz anechoic
Woofer Opening11.000 in, cut for AudioControl's frame
Frame Outer Diameter12.400 in
Bolt CircleNot published by AudioControl; threaded insert kit included
Driver Displacement0.094 cu ft, estimated; AudioControl publishes none for the EPICX
EPICX12 D2 (dual 2 ohm) Fs / Qts / Qes / Qms / Vas29.9 Hz / 0.547 / 0.595 / 6.83 / 59.2 L
EPICX12 D4 (dual 4 ohm) Fs / Qts / Qes / Qms / Vas30.3 Hz / 0.594 / 0.656 / 6.28 / 60.1 L
Driver Sd515 cm2, AudioControl spec
Xmax8.5 mm, one-way, method not stated
Driver Power Handling500 W RMS
Wiring OptionsAudioControl sells the EPICX12 as EPICX12 D2 (dual 2 ohm) and EPICX12 D4 (dual 4 ohm): the EPICX12 D2 (dual 2 ohm) is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel; the EPICX12 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 SourceAudioControl EPICX12 user manual
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 BracingWindowed brace, dadoed to the shell
Driver MountingThreaded insert kit and stainless machine screws included; inserts set at install, no bolt circle is published
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
Shipping Weight41 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
1.25
cu ft
System Qtc
0.89–0.98
sealed
Half power
39.6–40.7
Hz · F3
Xmax at
159
W RMS · no filter
With 25 Hz subsonic
169
W RMS · +6%
Amplifier
500
W RMS recommended
This enclosure holds 1.25 cu ft net . In it the AudioControl EPICX12 runs a system Qtc of 0.89–0.98 with half power at 39.6–40.7 Hz, and the cone reaches its 8.5 mm travel limit at 159 W, below the driver’s 500 W thermal rating, so travel is what stops you here, not heat. Run a subsonic filter at 25 Hz and that becomes 169 W — +10 W, or 6 percent more power for the same 8.5 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 46.2–50.3
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 EPICX12 D2 50.3 EPICX12 D4 46.2
EPICX12 D2 · EBP 50.3EPICX12 D4 · EBP 46.2
The EPICX12 straddles the boundary at 46.2–50.3 depending on coil — part sealed-band, part transition. Either way it takes a sealed load happily; the coil you run shifts the alignment more than it shifts this verdict.

02What the box does to it

1.25 cu ft against a 59.2 L Vas.

α = Vas ÷ Vb = 1.67  ·  Fc = Fs√(α+1) = 49–50 Hz  ·  Qtc = 0.89–0.98
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
EPICX12 D2 · Qtc 0.89, Fc 49 Hz, F3 40.7 HzEPICX12 D4 · Qtc 0.98, Fc 50 Hz, F3 39.6 Hz
The box lifts resonance from 29.9–30.3 Hz free-air to 49–50 Hz and half power lands at 39.6–40.7 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 8.5 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 159–160 W unfiltered  →  169–173 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 8.5 mm 159 W reaches Xmax here
EPICX12 D2 · 159 W, no filterEPICX12 D4 · 160 W, no filterEPICX12 D2 · 173 W with subsonic at 25 Hz, 24 dB/octEPICX12 D4 · 169 W with subsonic at 25 Hz, 24 dB/octXmax 8.5 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 8.5 mm. Unfiltered that is 159 W, reached first at 30 Hz. It sits under the 500 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 169 W before hitting the same 8.5 mm. That is 6 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs29.90 / 30.30Hzfree-air resonance
Qts0.547 / 0.594EPICX12 D2 / EPICX12 D4
Vas59.20 / 60.10Lequivalent compliance
Sd515.0cm²effective piston area
Xmax8.5mmone-way, method not stated
Pe500Wcontinuous RMS
SPL86.1dB1 W / 1 m, derived from T/S

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

From the shop floor

Installer's take

1.25 cubic feet: Qtc 0.894 on the EPICX12 D2 (dual 2 ohm) and Qtc 0.976 on the EPICX12 D4 (dual 4 ohm), F3 40.7 Hz on the EPICX12 D2 (dual 2 ohm) and 39.6 Hz on the EPICX12 D4 (dual 4 ohm).

Measure the installed height, not the cabinet height: 8.55 tall on its own, 10.30 with the standoffs on the 30 by 15 footprint.

Floor slot is 0.76 times the cone area at the 1.75 standoff, under the 1.0 I like. For hard use, taller feet or front firing.

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 500 watts or under per driver.

Before you order

Questions

Does this fit the AudioControl EPICX12, and will any other 12 inch fit?

The EPICX12, yes, in both coil versions. The baffle is cut to 11.000 in for AudioControl's 12.400 in frame. The 6.00 inch motor clears the cabinet with 1.80 inch to spare.

Any other 12, no. The airspace is engineered around the EPICX12'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.

Why 1.25 cubic feet, and what alignment does it target?

1.25 cubic feet net on AudioControl's published figures: the EPICX12 D2 (dual 2 ohm) reads Qtc 0.894 with resonance at 48.9 Hz and half power at 40.7 Hz, and the EPICX12 D4 (dual 4 ohm) reads Qtc 0.976 with resonance at 49.8 Hz and half power at 39.6 Hz. One cabinet serves both coils. That is AudioControl's own recommended sealed size for this driver, 1.25 cubic feet, between their 1 minimum and 1.5 maximum. That is well above maximally flat: a clear lift near resonance and extra midbass, the way AudioControl voices it in this size.

Cabinet gain in a vehicle lifts the bottom end further, so in the car this reads deeper than the anechoic figures.

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

AudioControl rates the EPICX12 at 500 watts RMS, so target 350 to 500 watts RMS at the final load.

AudioControl sells the EPICX12 as EPICX12 D2 (dual 2 ohm) and EPICX12 D4 (dual 4 ohm): the EPICX12 D2 (dual 2 ohm) is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel; the EPICX12 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.

How tall is this once the standoffs are on?

The cabinet is 8.55 inches tall measured in the down fire position, and that figure excludes the standoffs. The standoffs hold 1.75 inches under the baffle, so plan your space around a finished stack of roughly 10.30 inches.

The footprint is the standard Performance Optimized down fire platform, 30.00 inches wide by 15.00 deep. Height is the only dimension solved to the driver.

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 a 12 inch woofer puts on it at 500 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 12.400 inch frame, so the driver bolts to the inner layer.

What is the expected low-frequency extension?

Anechoic F3 is 40.7 Hz on the EPICX12 D2 (dual 2 ohm) and 39.6 Hz on the EPICX12 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.

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 1.25 cubic feet this cabinet was built to.

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, one side-mounted pre-wired terminal cup, the polyfill lining already in place, the standoffs, and a threaded insert kit with stainless machine screws.

The inserts are not pre-installed: AudioControl publishes no bolt circle for the EPICX12, so set the driver in its recess, mark its holes, drill and press the inserts. The AudioControl EPICX12 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 12 inch box.

Same series, same size

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