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Performance Optimized · Datasheet

Performance Optimized Wedge Sealed 12" Enclosure | Image Dynamics IDMAX12 V.4 Single 12" Sealed enclosure

Net volume
1.25 cu ft
Max mounting depth
8.071 in required
Cutout
11.024 in
External dimensions
21.92 in W × 15 in at the seat face H × 14.97 in at the base D
Front baffle
1.5 in, double baffle
Buy at Audio Intensity
  • Best For: Image Dynamics IDMAX12 V.4 Trunk-Fit Builds
  • Net Volume: 1.25 cu ft (1.40 cu ft Gross)
  • Alignment: Qtc 1.10 (D2) / 1.32 (D4), F3 32.5 to 34.3 Hz
  • Driver Match: IDMAX12 V.4 (D2 or D4)
  • Watch the impedance: a single D2 parallels to 1 ohm
  • Construction: Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Inserts

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Wedge
Compatible DriverImage Dynamics IDMAX12 V.4, quantity 1. Direct fit, either coil version
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 Width21.92 in
External Height15 in at the seat face
External Depth14.97 in at the base, tapering to 9.51 in at the top
Internal Volume, Gross1.40 cu ft
Internal Volume, Net Acoustic1.25 cu ft
AlignmentQtc 1.097 (D2) / 1.323 (D4), fc 45.3 Hz, F3 32.5 to 34.3 Hz anechoic
Driver Cutout11.024 in
Driver Mounting Depth8.071 in required
Power Handling500 watts RMS
Impedance OptionsD2: 4 ohms series, 1 ohm parallel. D4: 8 ohms series, 2 ohms parallel
MaterialLangboard Elite MDF
ConstructionCNC cut, V-groove and dado joinery
Panel Thickness0.75 in
Front Baffle1.5 in, double baffle
Internal BracingWindowed C brace
Driver MountingThreaded inserts at every mounting location, stainless machine screws included
Terminal CupsOne Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
DampingLight polyfill wall lining, does not alter acoustic volume
CarpetPlush black
Weight33.6 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Performance in this enclosure

Net airspace
1.25
cu ft per chamber
System Qtc
1.10–1.32
sealed
Half power
32.5–34.3
Hz · F3
Xmax at
702
W RMS · no filter
With 25 Hz subsonic
723
W RMS · +3%
Amplifier
500
W RMS recommended
This enclosure holds 1.25 cu ft net per chamber. In it the Image Dynamics IDMAX12 V.4 runs a system Qtc of 1.10–1.32 with half power at 32.5–34.3 Hz, and the cone reaches its 19.0 mm travel limit at 702 W, above the driver’s 500 W thermal rating, so heat stops you before travel does. A 25 Hz subsonic filter adds little here: 723 W against 702 W, 3 percent. The box already resonates at 45 Hz, so its own rolloff has removed most of what the filter would have stopped.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 29.2–35.6
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D2 35.6 D4 29.2
D2 · EBP 35.6D4 · EBP 29.2
EBP under 50 means a motor that wants a sealed load. The IDMAX12 sits at 29.2–35.6, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

1.25 cu ft against a 71.9 L Vas.

α = Vas ÷ Vb = 2.03  ·  Fc = Fs√(α+1) = 45 Hz  ·  Qtc = 1.10–1.32
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D2 · Qtc 1.10, Fc 45 Hz, F3 34.3 HzD4 · Qtc 1.32, Fc 45 Hz, F3 32.5 Hz
The box lifts resonance from 26.0 Hz free-air to 45 Hz and half power lands at 32.5–34.3 Hz, anechoic, before any cabin gain. Image Dynamics publishes a different Vas for the D2 and the D4. A cone and suspension are shared across coil variants, so both cannot be right. The figure here is the row whose moving mass reproduces its own free-air resonance, applied to both coils.

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 19.0 mm, and in this alignment a subsonic filter barely moves it.

PXmax = 702–774 W unfiltered  →  723–817 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 12 16 20 24 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 19.0 mm 702 W reaches Xmax here
D2 · 774 W, no filterD4 · 702 W, no filterD2 · 817 W with subsonic at 25 Hz, 24 dB/octD4 · 723 W with subsonic at 25 Hz, 24 dB/octXmax 19.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 19.0 mm. Unfiltered that is 702 W, reached first at 38 Hz. It sits above the 500 W the driver can take thermally, so the voice coil gives up before the suspension does. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct, and they sit almost on top of the solid ones: 723 W against 702 W. At 45 Hz the filter sits well below resonance, where the sealed alignment has already rolled the cone off at 12 dB/oct, so there is little wasted travel left for it to recover. Set it anyway to keep road rumble out of the cone, but do not size the amplifier around it.
ParamValueUnitNote
Fs26.00Hzfree-air resonance
Qts0.630 / 0.760D2 / D4
Vas71.90 / 71.90Lequivalent compliance
Sd547.0cm²effective piston area
Xmax19mmone-way linear travel, bolt-on field-replaceable basket
Pe500Wcontinuous RMS
SPL84.2dB1 W / 1 m, derived from T/S

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

Installer's take

Read the alignment before you read anything else. This is a high-Q sealed box: Qtc 1.10 on the D2 and 1.32 on the D4. That is Image Dynamics' own recommended airspace doing what it does, not a compromise we made. The IDMAX publishes a high Qts, 0.63 and 0.76 on the two coils, and a sealed system Q can never go below the driver's own Qts no matter how big you build.

What that buys you is a rise around 45 Hz and a half power point of 32.5 to 34.3 Hz anechoic, which is lower than a flatter box this size would reach. In a vehicle the cabin does the rest below that. If you want a damped, dry alignment out of an IDMAX, no cabinet that fits a trunk will give it to you.

Check the impedance before you buy the amplifier. A single D2 is 4 ohms in series or 1 ohm in parallel, a D4 is 8 or 2.

Measure the base depth. This cabinet is 14.97 inches deep at the trunk floor, 9.51 at the top, and 21.92 wide. The floor dimension is what decides whether it goes in.

Questions

Will this enclosure fit both the IDMAX12 V.4 D2 and D4?

Yes. Both coil versions share the same frame, the same 11.024 in cutout and the same 8.071 in mounting depth, so the baffle is cut once and fits either. Acoustically they differ more than usual on this driver: Qtc 1.097 on the D2 against 1.323 on the D4, because Image Dynamics publishes a different Vas for each coil.

Why 1.25 cubic feet net?

That is Image Dynamics' published Universal sealed airspace for the IDMAX12 V.4. Gross is 1.40 cu ft before the driver's 0.1398 cu ft displacement. It produces Qtc 1.097 to 1.323, a high-Q sealed alignment rather than a flat one, which is what this driver's own Qts of 0.63 to 0.76 allows.

What amplifier power should I run, and what impedance?

The IDMAX12 V.4 is rated 500 watts RMS each, so 500 across the one driver. On impedance: a D2 gives 4 ohms series, 1 ohm parallel and a D4 gives 8 ohms series, 2 ohms parallel. Aim for roughly 350 to 500 watts at the final wired impedance.

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 and smooths the presentation into the cabin.

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 19 mm of one-way travel and 500 watts on tap, that matters here more than it does on a shallow driver.

What is the expected low-frequency extension?

Anechoic F3 lands between 32.5 and 34.3 Hz depending on coil, at Qtc 1.097 to 1.323. That is a peaked alignment, not a flat one: there is a rise around 45 Hz before the rolloff. Those figures exclude cabin gain, which in most vehicles adds meaningful output below 40 Hz.

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 would push Qtc the wrong way for no gain in extension.

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.

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