It is 44 inches wide, 17 tall and 14.85 deep at the base, tapering to 8.66 at the top. Measure between the rear wheel wells, the floor depth with the seat upright, and the height under your cargo cover.The raked face goes against the seat back and the woofers fire toward the liftgate.

Proline X

Performance Optimized Wedge Wide Sealed Quad 10" Enclosure | Ground Zero GZHW 25

Q: Does this fit the Ground Zero GZHW 25, and its coil versions?

Yes. Each opening is cut to 9.370 in for the 10.79 in frame, and the 7.00 in deep motor clears the raked rear panel with 0.75 in to spare. Coil versions of the Ground Zero GZHW 25 share the frame, cutout and mounting depth, so any of them drops in. The alignment on this page is computed on the GZHW 25 / GZHW 25XSPL D1 parameters.Run four matched drivers, same model and same coil, so every chamber sees the alignment on this page.

Q: Why 0.711 cubic feet per driver, and what alignment does it target?

On Ground Zero's published Fs 40.3 Hz, Qts 0.515 and Vas 9.9 liters, 0.711 cubic feet per driver gives Qtc 0.629, system resonance 49.2 Hz and half power 56.1 Hz.The 7.00 in deep motor sets the shallowest the wedge can be, and that smallest box is still more air than flat wants, so it lands below 0.707: tighter and more damped, trading a little extension for control.

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

Ground Zero rates the GZHW 25 at 1200 watts RMS per driver. Recommended amplifier: 840 to 1200 W RMS per driver, 3,360 to 4,800 W RMS for the full set of 4.Each GZHW 25 / GZHW 25XSPL D1 has two 1 ohm voice coils, 2 ohms in series or 0.5 ohms in parallel. Wire every driver's coils in series. With the two drivers in each chamber in parallel and the two cups in parallel, the four present 0.5 ohms to a mono amplifier. With the two drivers in each chamber in series and the two cups in parallel, they present 2 ohms. Use the lower load only on an amplifier rated stable there.

Q: Why two drivers per chamber instead of four chambers?

Four chambers would need three dividers, and on a 44 inch face that space is needed for the woofers. Two matched drivers in one sealed chamber move together and see the same pressure, so each behaves as if it had half the chamber to itself: 0.711 cubic feet per driver here.It also gives two terminal cups, one per pair, which keeps the wiring to the amplifier simple.

Q: What is the expected low-frequency extension?

Anechoic F3 is 56.1 Hz per driver with system resonance at 49.2 Hz.Those figures exclude cabin gain. An SUV cabin adds real output below about 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 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 0.711 cubic feet per driver.

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, two side-mounted pre-wired terminal cups, the polyfill lining in place, threaded inserts and stainless machine screws.Bring four matched Ground Zero GZHW 25 drivers. The cabinet is cut direct fit to them, not a general purpose 10 inch box.

SKU: PO 10Q-S W GZHW25 BB

QUICK SPECS

Best For: Quad Ground Zero GZHW 25 SUV Cargo-Floor Builds
Net Volume: 0.711 cu ft per Driver (2.84 cu ft Net Total)
Driver Match: Four Ground Zero GZHW 25 (D1), matched
Construction: 2 Chambers | 44" Wide Wedge | V-Groove/Dado | Double 1.5" Baffle | 2 Terminal Cups

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.

$ 489.99

Acrylic Insert Color

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Performance Optimized Wedge Wide Sealed Quad 10" Enclosure | Ground Zero GZHW 25

More enclosures cut for Ground Zero subwoofers: Ground Zero Subwoofer Boxes

Enclosure Type Sealed

External Dimensions 44" W x 17" H x 14.85" D at base tapering to 8.66" D at top

Gross Volume 3.26 cu ft

Net Volume 2.84 cu ft

Shipping Weight 75 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

Start with the size. 0.711 cubic feet per driver puts the GZHW 25 at Qtc 0.629, resonance 49.2 Hz, half power 56.1 Hz anechoic. The 7.00 in deep motor sets the shallowest the wedge can be, and that smallest box is still more air than flat wants, so it lands below 0.707: tighter and more damped, trading a little extension for control.

Measure the base depth, not the top. This cabinet is 14.85 in deep where it meets the floor, 8.66 at the top, 44 wide and 17 tall. In an SUV the 44 has to clear between the rear wheel wells at floor height, the base depth is measured from the seat back with the seat upright and latched, and the 17 has to clear the cargo cover.

The two terminal cups are on the side panels, one per chamber, so they sit close to the wheel wells. Land the speaker wire on both before the box slides into its final spot, with slack to pull it forward again.

Two drivers share each chamber, so they have to match: same model, same coil, wired in phase. One driver reversed in a shared chamber pushes against its partner and the pair cancels instead of adding. Check polarity at each cup with a battery tap before the box goes in. The outer pair sits 3.04 in lower than the inner pair on purpose: that is how four 10.79 in frames fit across 44 in. The frames mount on the face rather than in a recess.

Impedance. GZHW 25 / GZHW 25XSPL D1: wire for 2 ohms (coils in series, each chamber's pair in series, both cups in parallel), the load most monoblocks are built to deliver full power into; 0.5 ohms is the other clean option (coils in series, each chamber's pair in parallel, both cups in parallel). Work the load out before you buy the amplifier, not after.

Power. Size the amplifier for the set, not one driver: 840 to 1200 W RMS per driver is 3,360 to 4,800 W RMS across all 4 at 2 ohms. At 4,800 W the charging system is part of the install: alternator output, the big three, and a battery that holds voltage under load.

Ground Zero's Qes and Qms reproduce the printed Qts within 3 percent, so the alignment rests on a self-consistent set. Ground Zero do not publish driver displacement; we deduct an estimated 0.089 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 0.63.

Product Details

Performance Optimized Wedge Wide | Quad Ground Zero GZHW 25

Quad 10" Sealed Wedge Enclosure | Built for SUV Cargo Floors

0.711 ft3 Net per Driver2.84 ft3 Net TotalQtc 0.632 Sealed Chambers44" x 17" x 8.66/14.85"Built in Tennessee

Four Ground Zero GZHW 25 in a 44 Inch Sealed Wedge

The wide wedge is a fixed SUV platform: 44 inches across and 17 tall, built to span a cargo floor against the rear seat. Depth is the only dimension that moves, and it is solved for the driver. Here it runs 8.66 in at the top to 14.85 in at the base.

0.711 cubic feet net per driver on Ground Zero's published Fs 40.3 Hz, Qts 0.515 and Vas 9.9 liters: Qtc 0.629, system resonance 49.2 Hz, half power 56.1 Hz. The 7.00 in deep motor sets the shallowest the wedge can be, and that smallest box is still more air than flat wants, so it lands below 0.707: tighter and more damped, trading a little extension for control.

Two Chambers, Two Drivers Each

A bonded full-height 3/4 inch MDF divider splits the cabinet into two sealed chambers of 1.422 cubic feet net. Each chamber carries two drivers, so each driver works into 0.711 cubic feet; both drivers in a chamber see the same pressure, which is why they must be a matched pair. Two pre-wired terminal cups, side mounted, one per chamber; each cup feeds the two drivers in its chamber.

Four 10.79 in frames will not sit flat in a row on a 44 inch face, so the woofers are staggered on the height: the outer pair sits 3.04 in below the inner pair, mirrored left to right, and every frame keeps clear of its neighbor and of the cabinet edge.

Cargo-Floor Wedge Design

The woofers mount on the vertical face and fire rearward toward the liftgate. The raked face goes against the rear seat back.

Raked Face Matches the Seat

A 20 degree rear panel follows the lean of a rear seat back.

44 Inches Across

Built to span a cargo floor. Measure between the rear wheel wells.

17 Inches Tall

Check it against your cargo cover and rear glass before you order.

14.85 Inches Deep at the Base

Measure the cargo floor before you order.

Engineered for the Ground Zero GZHW 25

Half power lands at 56.1 Hz anechoic, before cabin gain. Ground Zero does not publish driver displacement, so an estimated 0.089 cubic feet per driver is taken out of the net figure.

Alignment Numbers (Per Driver)

Driver	System Qtc	fc	F3
GZHW 25 / GZHW 25XSPL D1	Qtc 0.629	49.2 Hz	56.1 Hz

Mounting Geometry

Each opening is cut to 9.370 in for the 10.79 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 8.66 in at the top to 14.85 in at the base, and the 7.00 in deep motor clears it with 0.75 in to spare.

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 fold, sides and dividers seated in dados.

Double-Layer 1.5" Front Baffle

Two bonded 3/4 in MDF sheets at the driver face, frames mounted on the face.

Ground Zero's Own Parameters

Fs 40.3 Hz, Qts 0.515, Qes 0.550, Qms 8.154, Vas 9.9 L, Sd 346 cm2, Xmax 22 mm.

Wiring Four Ground Zero GZHW 25 to Your Amplifier

Each GZHW 25 / GZHW 25XSPL D1 has two 1 ohm voice coils, 2 ohms in series or 0.5 ohms in parallel. Wire every driver's coils in series. With the two drivers in each chamber in parallel and the two cups in parallel, the four present 0.5 ohms to a mono amplifier. With the two drivers in each chamber in series and the two cups in parallel, they present 2 ohms. Use the lower load only on an amplifier rated stable there.

Ground Zero rates the driver at 1200 watts RMS each, 4800 across all four. Recommended amplifier: 840 to 1200 W RMS per driver, 3,360 to 4,800 W RMS for the full set of 4.

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, two side-mounted pre-wired terminal cups, 12 gauge OFC. Polyfill wall lining installed in every chamber. Threaded inserts at every mounting location, stainless machine screws in the box. 1 year limited warranty. Enclosure only, the drivers are purchased separately. Call or text 931-563-5151.

Quad Ground Zero GZHW 25: 44 Inch SUV Sealed Wedge

0.711 cubic feet net per driver at Qtc 0.629, F3 56.1 Hz, cut direct fit and built to order in Tennessee.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge Wide
Compatible Driver	Ground Zero GZHW 25, quantity 4, matched. Direct fit
Configuration	Quad 10 inch sealed wedge, 2 chambers, 2 drivers per chamber
Mounting Position	SUV cargo floor, raked face against the rear seat back
Firing Direction	Rearward toward the liftgate. Not a down fire design
External Width	44 in
External Height	17 in at the seat face
External Depth	14.85 in at the base, tapering to 8.66 in at the top
Internal Volume, Gross	3.26 cu ft total
Internal Volume, Net Acoustic	0.711 cu ft per driver, 2.84 cu ft total, after the divider and an estimated 0.089 cu ft displacement per driver
Driver Mounting Depth	7.00 in required; 0.75 in clearance above the motor against the raked rear panel
Alignment Per Driver	GZHW 25 / GZHW 25XSPL D1 Qtc 0.629, fc 49.2 Hz, F3 56.1 Hz anechoic
Woofer Openings	4 at 9.370 in
Woofer Layout	Staggered on the height, outer pair low, inner pair high
Frame Outer Diameter	10.79 in
Fs / Qts / Qes / Qms	40.3 Hz / 0.515 / 0.550 / 8.154
Vas / Sd / Xmax	9.9 L / 346 cm2 / 22 mm
Driver Power Handling	1200 W RMS per driver, 4800 W RMS for the set of 4 (thermal rating)
Recommended Amplifier	840-1200 W RMS per driver, 3,360-4,800 W RMS for the full set, at 2 ohms
Parameter Source	Ground Zero published specifications
Material	Langboard Elite MDF
Construction	CNC cut, V-groove and dado joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in double baffle, frames face mounted
Internal Bracing	One full-height 3/4 in divider
Driver Mounting	Threaded inserts, stainless machine screws included
Terminal Cups	Two Proline X ABS and carbon fiber composite, side mounted, one per chamber, pre wired 12 gauge OFC
Acrylic Insert	Gloss black acrylic baffle insert standard; None variant minus $20
Damping	Light polyfill wall lining in every chamber, does not alter acoustic volume
Carpet	Plush black
Shipping Weight	75 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

0.711

cu ft per driver

System Qtc

0.63

sealed

Half power

56.1

Hz · F3

Xmax at

1513

W RMS per driver · no filter

With 25 Hz subsonic

2164

W RMS per driver · +43%

Amplifier, per driver

840–1200

W RMS recommended

This enclosure holds 0.711 cu ft net per driver. In it the Ground Zero GZHW 25 / GZHW 25XSPL D1 runs a system Qtc of 0.63 with half power at 56.1 Hz, and the cone reaches its 22.5 mm travel limit at 1513 W per driver, above the driver’s 1200 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 2164 W per driver — +651 W, or 43 percent more power for the same 22.5 mm of travel.

00Sizing the amplifier

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

Per driver 840–1200 W RMS × 4 drivers = full set 3,360–4,800 W RMS at 2 ohms

Look for a mono amplifier rated 3,360–4,800 W RMS at 2 ohms, the load the set wires to most easily. The top is the driver’s 1200 W thermal rating; with the 25 Hz subsonic set the cone still has travel to spare there, reaching Xmax only at 2164 W. 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 = 73.3

D1 · EBP 73.3

At 73.3 the GZHW 25 / GZHW 25XSPL D1 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

0.711 cu ft against a 9.9 L Vas.

α = Vas ÷ Vb = 0.49 · Fc = Fs√(α+1) = 49 Hz · Qtc = 0.63

D1 · Qtc 0.63, Fc 49 Hz, F3 56.1 Hz

The box lifts resonance from 40.3 Hz free-air to 49 Hz and half power lands at 56.1 Hz, anechoic, before any cabin gain. Figures are Ground Zero’s published parameters; Qes and Qms reproduce the printed Qts. This cabinet holds four drivers in two sealed chambers of 1.422 cubic feet, two drivers to a chamber, so each driver works into 0.711 cubic feet and that is 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 22.5 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

P_Xmax = 1513 W per driver unfiltered → 2164 W per driver with a 25 Hz subsonic

D1 · 1513 W, no filterD1 · 2164 W with subsonic at 25 Hz, 24 dB/octXmax 22.5 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 22.5 mm. Unfiltered that is 1513 W per driver, reached first at 20 Hz. It sits above the 1200 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: stopping the cone wasting travel below the passband lets it take 2164 W per driver before hitting the same 22.5 mm. That is 43 percent more amplifier for the price of one filter setting.

Param	Value	Unit	Note
Fs	40.30	Hz	free-air resonance
Qts	0.515		D1
Vas	9.91	L	equivalent compliance
Sd	346.4	cm²	effective piston area
Xmax	22.5	mm	one-way linear travel
Pe	1200	W	continuous RMS
SPL	82.6	dB	1 W / 1 m, derived from T/S

Driver parameters as published by Ground Zero GZHW 25 / GZHW 25XSPL D1 published specifications. Curves computed against this enclosure’s actual net airspace.

Customer Installs

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.