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Performance Optimized · Datasheet

AudioControl Space SPC-12 Box: Sealed 12" Shallow Wedge Enclosure Single 12" Sealed enclosure

Net volume
1.25 cu ft after the brace and the driver displacement
Max mounting depth
3.94 in required; 1.91 in clearance above the motor against the raked rear panel
External dimensions
29.50 in W × 15 in at the seat face H × 12.00 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 Space SPC-12Buy at Audio Intensity
  • Best For: AudioControl Space SPC-12 Trunk-Fit Builds
  • Net Volume: 1.25 cu ft (1.32 cu ft Gross)
  • Driver Match: AudioControl Space SPC-12 (SPC-12S2 (single 2 ohm) and SPC-12S4 (single 4 ohm))
  • Construction: Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Insert Kit

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Wedge
Compatible DriverAudioControl Space SPC-12 (SPC-12S2 (single 2 ohm) and SPC-12S4 (single 4 ohm)), quantity 1. Direct fit
ConfigurationSingle 12 inch, single chamber sealed wedge
Mounting PositionTrunk or cargo area, tall face against the rear seat back
Firing DirectionRearward into the trunk. Not a down fire design, no feet included
External Width29.50 in
External Height15 in at the seat face
External Depth12.00 in at the base, tapering to 6.54 in at the top
Internal Volume, Gross1.32 cu ft
Internal Volume, Net Acoustic1.25 cu ft after the brace and the driver displacement
Driver Mounting Depth3.94 in required; 1.91 in clearance above the motor against the raked rear panel
Alignment, SPC-12S2 (single 2 ohm)Qtc 0.743, fc 49.1 Hz, F3 46.8 Hz anechoic
Alignment, SPC-12S4 (single 4 ohm)Qtc 0.850, fc 52.3 Hz, F3 44.9 Hz anechoic
Woofer Opening11.100 in, cut for AudioControl's frame
Frame Outer Diameter12.370 in
Bolt CircleNot published by AudioControl; threaded insert kit included
Driver Displacement0.0619 cu ft, AudioControl spec
SPC-12S2 (single 2 ohm) Fs / Qts / Qes / Qms / Vas27.843 Hz / 0.4216 / 0.4703 / 4.0762 / 74.5578 L
SPC-12S4 (single 4 ohm) Fs / Qts / Qes / Qms / Vas30.7061 Hz / 0.4996 / 0.5764 / 3.7494 / 67.1494 L
Driver Sd511 cm2, AudioControl spec
Xmax9 mm, one-way, method not stated
Driver Power Handling400 W RMS
Wiring OptionsAudioControl sells the SPC-12 as SPC-12S2 (single 2 ohm) and SPC-12S4 (single 4 ohm): the SPC-12S2 (single 2 ohm) is a single 2 ohm coil, a 2 ohm load; the SPC-12S4 (single 4 ohm) is a single 4 ohm coil, a 4 ohm load. A parallel load at or under 1 ohm needs an amplifier rated for it.
Parameter SourceAudioControl Space Series user manual
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 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
Acrylic InsertGloss black acrylic baffle insert standard
DampingLight polyfill wall lining, does not alter acoustic volume
CarpetPlush black
Shipping Weight47 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
1.25
cu ft
System Qtc
0.74–0.85
sealed
Half power
44.9–46.8
Hz · F3
Xmax at
160
W RMS · no filter
With 25 Hz subsonic
199
W RMS · +24%
Amplifier
400
W RMS recommended
This enclosure holds 1.25 cu ft net . In it the AudioControl SPC-12 runs a system Qtc of 0.74–0.85 with half power at 44.9–46.8 Hz, and the cone reaches its 9.0 mm travel limit at 160 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 199 W — +39 W, or 24 percent more power for the same 9.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 53.3–59.2
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 SPC-12S2 59.2 SPC-12S4 53.3
SPC-12S2 · EBP 59.2SPC-12S4 · EBP 53.3
At 53.3–59.2 the SPC-12 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 74.6 L Vas.

α = Vas ÷ Vb = 2.11  ·  Fc = Fs√(α+1) = 49–52 Hz  ·  Qtc = 0.74–0.85
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
SPC-12S2 · Qtc 0.74, Fc 49 Hz, F3 46.8 HzSPC-12S4 · Qtc 0.85, Fc 52 Hz, F3 44.9 Hz
The box lifts resonance from 27.8–30.7 Hz free-air to 49–52 Hz and half power lands at 44.9–46.8 Hz, anechoic, before any cabin gain. Parameters are AudioControl’s own user manual for each coil plotted. 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 9.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 160–190 W unfiltered  →  199–206 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 9.0 mm 160 W reaches Xmax here
SPC-12S2 · 160 W, no filterSPC-12S4 · 190 W, no filterSPC-12S2 · 199 W with subsonic at 25 Hz, 24 dB/octSPC-12S4 · 206 W with subsonic at 25 Hz, 24 dB/octXmax 9.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 9.0 mm. Unfiltered that is 160 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 199 W before hitting the same 9.0 mm. That is 24 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs27.84 / 30.71Hzfree-air resonance
Qts0.422 / 0.500SPC-12S2 / SPC-12S4
Vas74.56 / 67.15Lequivalent compliance
Sd511.0cm²effective piston area
Xmax9mmone-way, method not stated
Pe400Wcontinuous RMS
SPL87.2dB1 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 0.743 on the SPC-12S2 (single 2 ohm) and Qtc 0.850 on the SPC-12S4 (single 4 ohm), F3 46.8 Hz on the SPC-12S2 (single 2 ohm) and 44.9 Hz on the SPC-12S4 (single 4 ohm).

The 3.94 inch motor clears the raked back with 1.91 to spare; the airspace sets the rest of the cabinet.

AudioControl measures the 2 ohm and 4 ohm SPC-12 as separate drivers and they do not match, so every coil is aligned on its own figures. Their numbers hold together on every check I run.

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.

Before you order

Questions

Does this fit the AudioControl Space SPC-12, and will any other 12 inch fit?

The Space SPC-12, yes, in both coil versions. The baffle is cut to 11.100 in for AudioControl's 12.370 in frame. The 3.94 inch motor clears the cabinet with 1.91 inch to spare.

Any other 12, no. The airspace is engineered around the Space SPC-12'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 SPC-12S2 (single 2 ohm) reads Qtc 0.743 with resonance at 49.1 Hz and half power at 46.8 Hz, and the SPC-12S4 (single 4 ohm) reads Qtc 0.850 with resonance at 52.3 Hz and half power at 44.9 Hz. One cabinet serves both coils. That is AudioControl's own recommended sealed size for this driver, 1.25 cubic feet, between their 0.8 minimum and 1.7 maximum. That is a touch above maximally flat: a small lift near resonance and firm midbass.

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 Space SPC-12 at 400 watts RMS, so target 280 to 400 watts RMS at the final load.

AudioControl sells the SPC-12 as SPC-12S2 (single 2 ohm) and SPC-12S4 (single 4 ohm): the SPC-12S2 (single 2 ohm) is a single 2 ohm coil, a 2 ohm load; the SPC-12S4 (single 4 ohm) is a single 4 ohm coil, a 4 ohm load. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm your amplifier's minimum stable impedance first.

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 46.8 Hz on the SPC-12S2 (single 2 ohm) and 44.9 Hz on the SPC-12S4 (single 4 ohm) on this page.

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 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 12.370 inch frame, so the driver bolts to the inner layer and sits flush with the gloss black acrylic insert.

What is the expected low-frequency extension?

Anechoic F3 is 46.8 Hz on the SPC-12S2 (single 2 ohm) and 44.9 Hz on the SPC-12S4 (single 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 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 SPC-12, so set the driver in its recess, mark its holes, drill and press the inserts. The AudioControl Space SPC-12 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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