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Proline X PO 10-S DF GZRW250F sealed down fire enclosure, front panel on 1.75 inch feet, 30 by 7.1 inches.
Proline X PO 10-S DF GZRW250F sealed down fire enclosure, end panel with recessed terminal cup, 15 by 7.1 inches.

Performance Optimized · Datasheet

Performance Optimized Down Fire Sealed 10" Enclosure Ground Zero GZRW 250-D2 FLAT · Single 10" Sealed enclosure

Net volume
1.00 cu ft after the brace and the driver displacement
Max mounting depth
3.35 in required, 3.02 in clearance above the motor
External dimensions
30.00 in W × 7.12 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
Ground Zero GZRW 250-D2 FLATBuy at Audio Intensity
  • Alignment: 1.00 cu ft net, Qtc 0.81, F3 37.4 Hz
  • Driver: Ground Zero GZRW 250-D2 FLAT (dual 2 ohm), 400 W RMS, 22 mm Xmax, 3.35 in mounting depth
  • Standoffs: Included, 1.75 in, shipped uninstalled. Installed height near 8.87 in
  • Cabinet: 30.00"W x 15.00"D x 7.12"H in down fire position, excludes standoffs, square corners

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Down Fire
Compatible DriverGround Zero GZRW 250-D2 FLAT (dual 2 ohm), quantity 1. Direct fit
ConfigurationSingle 10 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 Height7.12 in in the down fire position, excludes standoffs
Installed Height8.87 in including the 1.75 in standoff
Internal Volume, Gross1.05 cu ft
Internal Volume, Net Acoustic1.00 cu ft after the brace and the driver displacement
Height Set ByAirspace; clearance alone would allow a lower cabinet
Driver Mounting Depth3.35 in required, 3.02 in clearance above the motor
Floor Slot0.92 times the cone area at the 1.75 in standoff
Alignment, dual 2 ohmQtc 0.813, fc 42.1 Hz, F3 37.4 Hz anechoic
Woofer Opening9.13 in, Ground Zero's published cutout
Frame Outer Diameter10.87 in
Bolt CircleNot printed by Ground Zero; threaded insert kit included
Driver Displacement0.038 cu ft, estimated; Ground Zero publishes none
dual 2 ohm Fs / Qts / Qes / Qms / Vas28 Hz / 0.54 / 0.6 / 5.53 / 35.8 L
Driver Sd350 cm2, derived from Ground Zero's Vas, Fs and moving mass
Xmax22 mm one way, Ground Zero spec
Driver Power Handling400 W RMS
Wiring OptionsGround Zero sells the GZRW 250-D2 FLAT as dual 2 ohm: the dual 2 ohm is two 2 ohm coils, 4 ohms in series or 1 ohm in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it.
Parameter SourceGround Zero GZRW 250-D2 FLAT owner's manual, specifications and dimension drawing
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 included, NOT pre-installed: Ground Zero prints no bolt circle
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 Weight39 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
1.00
cu ft
System Qtc
0.81
sealed
Half power
37.4
Hz · F3
Xmax at
604
W RMS · no filter
With 25 Hz subsonic
767
W RMS · +27%
Amplifier
400
W RMS recommended
This enclosure holds 1.00 cu ft net . In it the Ground Zero GZRW 250-D2 FLAT runs a system Qtc of 0.81 with half power at 37.4 Hz, and the cone reaches its 22.0 mm travel limit at 604 W, above the driver’s 400 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 767 W — +163 W, or 27 percent more power for the same 22.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 46.7
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D2 46.7
D2 · EBP 46.7
EBP under 50 means a motor that wants a sealed load. The GZRW 250-D2 FLAT sits at 46.7, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

1.00 cu ft against a 35.8 L Vas.

α = Vas ÷ Vb = 1.26  ·  Fc = Fs√(α+1) = 42 Hz  ·  Qtc = 0.81
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D2 · Qtc 0.81, Fc 42 Hz, F3 37.4 Hz
The box lifts resonance from 28.0 Hz free-air to 42 Hz and half power lands at 37.4 Hz, anechoic, before any cabin gain. Parameters are Ground Zero’s own owner’s manual table for the GZRW 250-D2 FLAT (dual 2 ohm). Cone area is not printed and is derived from their Vas, Fs and moving mass. Driver displacement is not published and is estimated.

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 22.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 604 W unfiltered  →  767 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 8 16 24 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 22.0 mm 604 W reaches Xmax here
D2 · 604 W, no filterD2 · 767 W with subsonic at 25 Hz, 24 dB/octXmax 22.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 22.0 mm. Unfiltered that is 604 W, reached first at 21 Hz. It sits above the 400 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 767 W before hitting the same 22.0 mm. That is 27 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs28.00Hzfree-air resonance
Qts0.540D2
Vas35.80Lequivalent compliance
Sd350.3cm²effective piston area
Xmax22mmone-way, as Ground Zero publish it
Pe400Wcontinuous RMS
SPL83.0dB1 W / 1 m, derived from T/S

Driver parameters as published by Ground Zero published T/S table. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

1.00 cubic feet: Qtc 0.813 on the dual 2 ohm, F3 37.4 Hz.

Measure the installed height, not the cabinet height: 7.12 tall on its own, 8.87 with the standoffs on the 30 by 15 footprint.

Floor slot is 0.92 times the cone area at the 1.75 standoff, under the 1.0 I like. For hard use, taller feet or front firing.

Ground Zero's manual is a full Klippel table and it checks out, but it prints no cone area, so that is derived; displacement is estimated.

A flat sealed box for this driver is 1.77 cubic feet, deeper than it is tall for a 10. At 1.0 the extension is within a hertz of that and the box fits a trunk; it just plays a little punchier.

At 3.35 inches of mounting depth this is a true shallow-mount 10: the motor clears the cabinet with room to spare.

Inserts ship in the kit, not pressed: Ground Zero prints no bolt circle. Mark from the driver, drill, press. 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 Ground Zero GZRW 250-D2 FLAT, and will any other 10 inch fit?

The GZRW 250-D2 FLAT, yes, in the dual 2 ohm version. The baffle is cut to 9.13 in, Ground Zero's published cutout, under the 10.87 in frame. The 3.35 inch motor clears the cabinet with 3.02 inch to spare.

Any other 10, no. The airspace is engineered around the GZRW 250-D2 FLAT'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 1.00 cubic feet, and what alignment does it target?

1.00 cubic feet net on Ground Zero's published figures: the dual 2 ohm reads Qtc 0.813 with resonance at 42.1 Hz and half power at 37.4 Hz. Ground Zero publishes no sealed volume for the GZRW 250-D2 FLAT. A maximally flat box would take 1.77 cubic feet, a 10 inch cabinet deeper than it is tall, for barely half a hertz more extension, so this one is built at 1.0 cubic foot: the same reach in a box that fits. 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?

Ground Zero rates the GZRW 250-D2 FLAT at 400 watts RMS, so target 280 to 400 watts RMS at the final load.

Ground Zero sells the GZRW 250-D2 FLAT as dual 2 ohm: the dual 2 ohm is two 2 ohm coils, 4 ohms in series or 1 ohm 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 7.12 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 8.87 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 10 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 Ground Zero's 10.87 inch frame, so the driver bolts to the inner layer.

What is the expected low-frequency extension?

Anechoic F3 is 37.4 Hz. 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 1.00 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 ship loose on purpose: Ground Zero prints no bolt circle for the GZRW 250-D2 FLAT, so you set the driver in the recess, mark its holes, drill and press the inserts. The Ground Zero GZRW 250-D2 FLAT is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 10 inch box.

Same series, same size

Other Performance Optimized models