Proline X PO 12D-S W IDQ sealed wedge, front baffle with gloss black insert and pre-wired leads, 32 by 16 inches.

Proline X

Performance Optimized Wedge Sealed Dual 12" Enclosure | Image Dynamics IDQ 12

Q: Will this enclosure fit two IDQ12 V4, in either coil version?

Yes. Both positions are CNC cut to 10.937 in, which clears the 276 mm (10.866 in) cutout on Image Dynamics' IDQ12 template, the recess takes the 12.48 in frame, and the raked rear panel clears the 5.77 in motor with 5.01 in to spare. The D2 and D4 share the frame, cutout and depth, so either fits.Run a matched pair, both D2 or both D4, so the chambers behave the same and the wiring works out to a usable load.

Q: Why 1.25 cubic feet net per driver, and why is the Qtc above 1.0?

The IDQ12 V4 is a high-Qts driver, 0.68 on the D2 and 0.74 on the D4. A maximally flat 0.707 box would take about 21 cubic feet for the D2, and the D4 cannot reach 0.707 in any sealed volume, so every box a trunk can hold puts it near Qtc 1.0; that is the driver, not the cabinet.At 1.25 cubic feet per chamber the D2 sits at Qtc 1.048 and the D4 at 1.130, with a 1.5 to 2.0 dB rise centred near 70 Hz. The volume matches our dual IDMAX12 wedge and keeps the cabinet to 17.10 inches deep at the base; the single IDQ 12 wedge holds 1.40, which in a dual would have pushed the base past 18 inches.

Q: What amplifier power should I run, and what impedance?

The IDQ12 V4 is rated 375 watts RMS each, so 750 across the pair; target 262 to 375 watts per driver at the final load.A pair of D2 wires to 2 ohms (each driver in series, the pair in parallel) or 8 ohms; paralleling everything gives 0.5 ohm, which almost no amplifier runs. A pair of D4 wires to 1 ohm, which needs an amplifier rated 1 ohm stable, or 4 ohms, the safe answer on any amplifier. Confirm your amplifier's minimum stable impedance first.

Q: How does a wedge enclosure improve the sound in a trunk installation?

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 both drivers fire 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 figures on this page.

Q: Why two separate chambers instead of one shared one?

Two drivers sharing one sealed volume load each other: each driver's compression stroke becomes the pressure the other works against, which blurs the alignment either would have alone. A bonded full-height 3/4 inch divider gives each driver its own 1.25 cubic feet and its own polyfill.It also means a failure in one driver does not unload the other, and the alignment on this page is the alignment in each chamber, not an average across a shared box.

Q: What is the expected low-frequency extension?

Half power lands at 40.4 Hz on the D2 and 40.1 Hz on the D4, anechoic and per chamber, with system resonance at 52.4 and 53.5 Hz. At Qtc 1.05 to 1.13 the response rises 1.5 to 2.0 dB near 70 Hz before rolling off, so half power sits below resonance.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 in both chambers 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 per chamber this cabinet was built to.

Q: 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, one side-mounted pre-wired terminal cup to both positions, the polyfill lining in place, and threaded inserts pre-installed on Image Dynamics' 11.85 in bolt circle with stainless machine screws.Bring your own matched pair of IDQ12 V4, D2 or D4. The cabinet is cut direct fit to that driver, not a general purpose dual 12 box.

SKU: PO 12D-S W IDQ BB

QUICK SPECS

Best For: Dual Image Dynamics IDQ12 V4 Trunk-Fit Builds
Net Volume: 1.25 cu ft per chamber (2.77 cu ft Gross Total)
Driver Match: Pair of Image Dynamics IDQ12 V4 (D2 or D4), matched
Construction: Dual Chamber | Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | 1 Shared Terminal Cup

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.

$ 389.99

Acrylic Insert Color

Add a Woofer?

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Complete Your System

Image Dynamics Image Dynamics IDQ12 V4 12 inch Subwoofer $ 280.99

Divini DCAK4-ANL 4 gauge amplifier kit package, 100% OFC copper

Divini Divini DCAK4-ANL 4 Gauge OFC Amp Kit | 100% Copper Amplifier Wiring Kit $ 119.99

Performance Optimized Wedge Sealed Dual 12" Enclosure | Image Dynamics IDQ 12

Enclosure Type Sealed

External Dimensions 32.00" W x 16" H x 17.10" D at base tapering to 11.28" D at top

Gross Volume 2.77 cu ft

Net Volume 2.50 cu ft

Shipping Weight 59 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

1.25 per chamber, not the single's 1.40: at 1.40 a dual at the 32 inch cap runs 18.35 deep at the base, so this matches the IDMAX12 dual instead. 32.00 wide, 16 tall, 17.10 at the base.

The IDQ12 is a Qtc 1.0 class driver in any sealed box a car holds: D2 lands at 1.05, D4 at 1.13. If a customer asks for flat, the answer is a different driver, not a bigger box.

Cutout is cut to 10.937 like the single; Image Dynamics' template says 276 mm (10.866) and the 317 mm frame covers either. Inserts are pressed on their 301 mm bolt circle.

Wiring: a pair of D2 goes to 2 or 8 ohms, a pair of D4 to 1 or 4. Match the coils across the pair.

Polyfill is already in both chambers as a wall lining. Adding more makes the box act larger and walks the alignment off the volume it was built to.

Product Details

Performance Optimized Wedge | Dual Image Dynamics IDQ12 V4

Dual 12" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design

1.25 ft3 Net per Chamber2.77 ft3 GrossQtc 1.05 to 1.13Two Separate Chambers32.00" x 16" x 11.28/17.10"Built in Tennessee

A Pair of Image Dynamics IDQ12 V4 in a Sealed Wedge

The IDQ12 V4 is the 12 inch of Image Dynamics' IDQ line: 375 watts RMS, 14.5 mm of one-way excursion, 511 square centimeters of cone area and a 5.77 inch mounting depth, sold in dual 2 ohm and dual 4 ohm versions. The two coils share the frame, cutout and depth but not the motor figures, so this page prints an alignment for each. Parameters are the per-coil data for each version; the fit dimensions come from Image Dynamics' own IDQ12 cutout template.

1.25 cubic feet net per chamber. The IDQ12 V4 is a high-Qts driver, 0.68 on the dual 2 ohm coil and 0.74 on the dual 4 ohm, which is the Image Dynamics house character rather than a quirk of this box: a maximally flat sealed alignment would take about 21 cubic feet for the D2, and with Qts above 0.707 the D4 cannot reach it in any sealed volume. In this cabinet the D2 lands at Qtc 1.048 with system resonance at 52.4 Hz and half power at 40.4 Hz, the D4 at Qtc 1.130, 53.5 Hz and 40.1 Hz. Both carry a 1.5 to 2.0 dB rise centred near 70 Hz: a punchy sealed alignment, and this page shows that curve rather than a flat one.

Two Fully Separate Chambers

A bonded full-height 3/4 inch MDF divider splits the cabinet into two sealed chambers of 1.25 cubic feet net each. Two drivers sharing one volume load each other; the divider removes that, and each chamber carries its own polyfill.

The cabinet is pinned at the 32 inch dual width cap, 16 inches tall, 11.28 inches deep at the top and 17.10 at the base, with the depth absorbing the airspace. One shared side-mounted terminal cup feeds both driver positions.

Trunk-Load Wedge Design Explained

The drivers mount on the vertical trunk-lid-side face and fire 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 Woofers

Vertical baffle, cones 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 IDQ12 V4

Half power lands at 40.1 Hz (D4) to 40.4 Hz (D2) anechoic, before any cabin gain. The driver displacement, 0.10 cubic feet per driver, is already taken out of the net figure.

Alignment Numbers (Per Chamber)

Driver (per chamber)	System Qtc	fc	F3
IDQ12 V4, Dual 2 ohm	Qtc 1.048	52.4 Hz	40.4 Hz
IDQ12 V4, Dual 4 ohm	Qtc 1.130	53.5 Hz	40.1 Hz

Mounting Geometry

Vertical baffle CNC cut to 10.937 in at each position. Image Dynamics' template prints a 276 mm (10.866 in) cutout; the cut runs a few hundredths larger, matching our single IDQ 12 wedge, and the 12.48 in (317 mm) frame still covers it with margin. The rear panel rakes 20 degrees, so the cavity deepens from 11.28 in at the top to 17.10 in at the base, and the 5.77 in motor clears it with 5.01 in to spare. Threaded inserts are pressed on Image Dynamics' published 11.85 in (301 mm) bolt circle.

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 divider 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.

Per-Coil Parameters

D2: Fs 34 Hz, Qts 0.68, Qes 0.79, Qms 5.38, Vas 48.6 L. D4: Fs 35 Hz, Qts 0.74, Qes 0.87, Qms 5.01, Vas 47.2 L. Sd 511 cm2 both.

Wiring a Pair of IDQ12 V4 to Your Amplifier

Wire both drivers identically. With the dual 2 ohm version, each driver in series (4 ohms) and the pair in parallel gives 2 ohms, and each driver in series with the pair in series gives 8 ohms. Paralleling everything drops to 0.5 ohm, which almost no amplifier will run. With the dual 4 ohm version, each driver in parallel (2 ohms) and the pair in parallel gives 1 ohm, which needs an amplifier rated 1 ohm stable; each driver in parallel with the pair in series, or each in series with the pair in parallel, gives 4 ohms, the safe load on any amplifier. Confirm the final load against your amplifier's minimum stable impedance before powering the system.

Power handling is 375 watts RMS per driver, 750 across the pair. Aim for roughly 262 to 375 watts per driver 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 shared pre-wired terminal cup, 12 gauge OFC to both driver positions. Polyfill wall lining installed in both chambers. Threaded inserts pre-installed, stainless machine screws included. 1 year limited warranty. Enclosure only, the drivers are purchased separately. Call or text 931-563-5151.

Dual Image Dynamics IDQ12 V4: Built to 1.25 Cubic Feet per Chamber

Qtc 1.05 (D2) to 1.13 (D4), F3 40.1 Hz (D4) to 40.4 Hz (D2), cut direct fit to the IDQ12 V4 and built to order in Tennessee.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	Image Dynamics IDQ12 V4, D2 or D4, quantity 2. Direct fit
Configuration	Dual 12 inch, two separate chambers, 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	32.00 in, the dual width cap
External Height	16 in at the seat face
External Depth	17.10 in at the base, tapering to 11.28 in at the top
Internal Volume, Gross	2.77 cu ft total
Internal Volume, Net Acoustic	1.25 cu ft per chamber, 2.50 total, after the divider and 0.10 cu ft driver displacement per driver
Driver Mounting Depth	5.77 in required (Image Dynamics template); 5.01 in clearance above the motor against the raked rear panel
Alignment per Chamber, D2	Qtc 1.048, fc 52.4 Hz, F3 40.4 Hz anechoic; 1.5 dB rise near 71 Hz
Alignment per Chamber, D4	Qtc 1.130, fc 53.5 Hz, F3 40.1 Hz anechoic; 2.0 dB rise near 69 Hz
Butterworth Volume	D2 about 21 cu ft, not a practical box; D4 none, Qts above 0.707 cannot reach it sealed
Woofer Opening	10.937 in, two; Image Dynamics template prints 276 mm (10.866 in)
Frame Outer Diameter	12.48 in (317 mm), Image Dynamics template
Bolt Circle	11.85 in (301 mm), 8 holes, Image Dynamics template
Driver Displacement	0.10 cu ft per driver
Fs / Qts / Qes / Qms	D2 34 Hz / 0.68 / 0.79 / 5.38; D4 35 Hz / 0.74 / 0.87 / 5.01
Vas	D2 48.6 L; D4 47.2 L
Driver Sd	511 cm2
Xmax	14.5 mm one way
Driver Sensitivity	D2 86.4 dB, D4 86.0 dB at 1 W / 1 m
Driver Power Handling	375 W RMS per driver, 750 W across the pair
Wiring Options	Pair of D2: 2 ohm or 8 ohm. Pair of D4: 1 ohm or 4 ohm. See the wiring section
Parameter Source	Per-coil IDQ12 V4 data (loudspeakerdatabase.com); fit from Image Dynamics' IDQ12 cutout template
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	Full-height 3/4 in divider
Driver Mounting	Threaded inserts pre-installed, stainless machine screws included
Terminal Cups	One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC to both driver positions
Acrylic Insert	Gloss black acrylic baffle insert standard; None variant minus $20
Damping	Light polyfill wall lining in both chambers, does not alter acoustic volume
Carpet	Plush black
Shipping Weight	59 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

1.25

cu ft per chamber

System Qtc

1.05–1.13

sealed

Half power

40.1–40.4

Hz · F3

Xmax at

540

W RMS · no filter

With 25 Hz subsonic

553

W RMS · +3%

Amplifier

375

W RMS recommended

This enclosure holds 1.25 cu ft net per chamber. In it the Image Dynamics IDQ12 V4 runs a system Qtc of 1.05–1.13 with half power at 40.1–40.4 Hz, and the cone reaches its 14.5 mm travel limit at 540 W, above the driver’s 375 W thermal rating, so heat stops you before travel does. A 25 Hz subsonic filter adds little here: 553 W against 540 W, 3 percent. The box already resonates at 52–53 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 = 40.2–43.0

D2 · EBP 43.0D4 · EBP 40.2

EBP under 50 means a motor that wants a sealed load. The IDQ12 V4 sits at 40.2–43.0, 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 48.6 L Vas.

α = Vas ÷ Vb = 1.37 · Fc = Fs√(α+1) = 52–53 Hz · Qtc = 1.05–1.13

D2 · Qtc 1.05, Fc 52 Hz, F3 40.4 HzD4 · Qtc 1.13, Fc 53 Hz, F3 40.1 Hz

The box lifts resonance from 34.0–35.0 Hz free-air to 52–53 Hz and half power lands at 40.1–40.4 Hz, anechoic, before any cabin gain. Figures are the per-coil IDQ12 V4 data, both coils plotted because both are sold. The IDQ12 is a high-Qts driver, 0.68 on the dual 2 ohm and 0.74 on the dual 4 ohm, as most of the Image Dynamics line is: a maximally flat sealed box would take about 21 cubic feet for the D2 and cannot be reached at all by the D4, so every trunk-sized sealed box puts it near Qtc 1.0. At 1.25 cubic feet per chamber it lands at Qtc 1.05 to 1.13 with a 1.5 to 2.0 dB rise near 70 Hz; this page shows that curve, not a flat one. Each chamber of this dual holds 1.25 cubic feet, so every figure here is per driver.

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

P_Xmax = 540–545 W unfiltered → 553 W with a 25 Hz subsonic

D2 · 540 W, no filterD4 · 545 W, no filterD2 · 553 W with subsonic at 25 Hz, 24 dB/octD4 · 553 W with subsonic at 25 Hz, 24 dB/octXmax 14.5 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 14.5 mm. Unfiltered that is 540 W, reached first at 39 Hz. It sits above the 375 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: 553 W against 540 W. At 52–53 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.

Param	Value	Unit	Note
Fs	34.00 / 35.00	Hz	free-air resonance
Qts	0.680 / 0.740		D2 / D4
Vas	48.60 / 47.20	L	equivalent compliance
Sd	511.0	cm²	effective piston area
Xmax	14.5	mm	one-way linear travel
Pe	375	W	continuous RMS
SPL	85.7	dB	1 W / 1 m, derived from T/S

Driver parameters as published by loudspeakerdatabase.com per-coil data; fit from Image Dynamics’ own IDQ12 cutout template. Curves computed against this enclosure’s actual net airspace.

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.