Professional Series · Datasheet

Professional Series Ported 12" Enclosure Ground Zero GZRW 12XSPL · Single 12" Ported enclosure

Net volume
1.44 Cubic Feet
Tuning
35.5 Hz
Max mounting depth
6.540 Inches (Ground Zero Spec)
Cutout
11.340 Inches (Ground Zero Spec)
External dimensions
32.00 Inches W × 16.00 Inches H × 12.00 Inches D
Front baffle
Three 3/4" MDF layers, 2.25" total | Woofer Flush-Mounted In The Outer Layer
Buy at Audio IntensityFactory-direct, ships from Tullahoma
  • Alignment: 1.44 cu ft net vented at 35.5 Hz. F3 29.5 Hz anechoic, 4.43 dB passband ripple
  • Driver: Ground Zero GZRW 12XSPL SVC, 1000 W RMS, 22.5 mm Xmax, 31.80 Hz Fs
  • Build: Front-firing standard box, 2.25" three-layer baffle with the woofer flush-mounted in the outer layer, Ground Zero logo acrylic, dado joinery, 29.0 sq in front slot port beside the woofer with one bend along the back wall, port and excursion gated at 1200 W
  • Cabinet: 32.00" W x 16.00" H x 12.00" D, 54 lb, threaded insert kit included

Spec of record

Technical specifications

SeriesProline X Professional
Driver-Specific FitmentGround Zero GZRW 12XSPL SVC (SVC)
Enclosure TypePorted | Front-Firing Standard Box
External Width32.00 Inches
External Height16.00 Inches
External Depth12.00 Inches
Internal Volume (Gross)2.30 Cubic Feet
Internal Volume (Net After Displacement)1.44 Cubic Feet
Port TypeVertical Slot Beside The Woofer | Front Exit | One 90 Degree Bend Along The Back Wall
Port Geometry2.00 x 14.50 Inches, 29.0 Square Inches, 34.03 Inches Of Path
Port Area29.0 Square Inches
Port Tuning (Fb)35.5 Hz
Port Mouth1/2 In Roundover On All Four Edges, 46.5 Square Inches At The Face
Port Air Velocity21.8 m/s In The Channel, 13.6 m/s At The Mouth, At 1200 W (17.0 m/s Chuff Threshold)
Design Power Basis1200 W RMS (1.2 x The Driver Rating) For Port Velocity And Excursion
Predicted F329.5 Hz (Anechoic)
Passband Ripple4.43 dB (Anechoic)
Subsonic Filter28 Hz High-Pass, 24 dB/Octave - REQUIRED On A Vented Enclosure
Driver Fs31.80 Hz
Driver Qts0.684
Driver Qes / Qms0.758 / 7.028
Driver Vas27.200 Liters / 0.961 Cubic Feet
Driver Sd521.3 Square Centimeters
Driver BL18.34
Driver Re3.9 Ohm
Driver Xmax22mm (One-Way)
Driver Displacement0.11 Cubic Feet (Published by Ground Zero)
Driver Sensitivity83.0 dB
Driver Power Handling1000 Watts RMS
Driver Overall Diameter12.240 Inches (Ground Zero Spec)
Mounting Depth Required6.540 Inches (Ground Zero Spec)
Cutout Diameter11.340 Inches (Ground Zero Spec)
Flush Mount Recess13.250 Inches In The Outer Layer
MaterialLangboard Elite 3/4" MDF
ConstructionShopSabre CNC / Two Windowed Braces Front To Back Either Side Of The Woofer
JoineryDado Joinery (CNC-Cut), Flat Panels
Front Baffle ConstructionThree 3/4" MDF layers, 2.25" total | Woofer Flush-Mounted In The Outer Layer
Baffle Layers3
AcrylicGlossy Black Ground Zero Logo Insert, Outer Layer, Standard
Mounting HardwareThreaded Insert Kit Included: 8-12 Inserts, Drill Bit, 2.5 In Allen-Head Screws, Allen Key, Gasket Tape
Voice Coil ConfigurationSVC
Terminal CupProline X ABS/Carbon Fiber Composite | Back Panel, Terminal-Cup Side | 12g OFC Pre-Wired
DampingNone - Ships Dry. Polyfill Detunes A Ported Enclosure
Recommended Power700-1000 Watts RMS (Ground Zero Rated: 1000W RMS)
Carpet FinishPlush Black
Weight54 lb
ShippingUPS Ground Parcel, Included In The 48 States
Bundle OptionsEnclosure Only (Bring Your Own Ground Zero GZRW 12XSPL)
Warranty2-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA

Modelled response

Performance in this enclosure

Net airspace
1.44
cu ft
Tuning
35.5
Hz · Fb
Half power
29.5
Hz · F3, anechoic
Xmax at
6010
W RMS · 28 Hz subsonic
With NO filter
1066
W RMS · unfiltered
Port
13.6
m/s at the mouth · 1200 W

01Is this driver right for a ported box?

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

EBP = Fs ÷ Qes = 42.0
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 EBP 42.0
Ground Zero GZRW 12XSPL SVC · EBP 42.0
Under 50 the raw number leans sealed. The Ground Zero GZRW 12XSPL SVC reads 42.0, so this is a ported build against the grain of its own EBP: it works because the alignment is tuned for in-car response rather than for an anechoic curve, and because the cabinet holds port area and volume the driver can actually use.

02What the box does to it

1.44 cu ft net against a 27.2 L Vas, vented at 35.5 Hz.

Fb = 35.5 Hz  ·  F3 = 29.5 Hz  ·  passband ripple 4.43 dB
20 30 50 70 100 150 200 +16 +12 +8 +4 0 −4 −8 −12 −16 −20 −24 −28 FREQUENCY · Hz LEVEL · dB −3 dB Fb 35.5
Ground Zero GZRW 12XSPL SVC · Fb 35.5 Hz, F3 29.5 Hz
Anechoic, before any cabin gain, with the 28 Hz subsonic filter already applied. The vent takes over below 36 Hz and the cone stops doing the work there, which is what holds travel down at the bottom of the passband.

03Ported vs Sealed

No sealed comparison is shown for this driver.

A ported-versus-sealed chart is only worth reading against a sealed box someone would actually build: the one we make for the driver, or the one its maker recommends. Neither exists for the Ground Zero GZRW 12XSPL SVC — we do not build a sealed enclosure for it and Ground Zero publish no sealed volume for it — so rather than compare this cabinet against itself stuffed and sealed, a box no one would build, the comparison is left out.

04The 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 Ground Zero's published 22.5 mm. The two traces are the same cabinet with the subsonic filter switched on and switched off.

PXmax = 6010 W with a 28 Hz subsonic  ·  1066 W with none  →  the filter is worth 5.6×
20 30 50 70 100 150 200 0 8 16 24 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 22.5 mm 6010 W reaches Xmax here
6010 W · subsonic at 28 Hz, 24 dB/oct1066 W · no subsonic filterXmax 22.5 mm one-way, published
Each trace touches the limit and no further, because each is drawn at the exact power that puts the cone on 22.5 mm. With a 28 Hz subsonic that takes 6010 W, reached first at 26 Hz. Take the filter away and the same cabinet reaches 22.5 mm on 1066 W — the filter is worth 5.6× the safe power. A vent unloads the cone below tuning, so there is nothing holding it once the box stops loading: on a sealed build a subsonic filter is an improvement, here it is required equipment. The unfiltered trace is still rising where this chart stops at 20 Hz, so treat 1066 W as a bound rather than a floor. Every wattage on this page is a MECHANICAL limit, not an electrical one. It is the power at which the cone runs out of linear travel in this cabinet, and nothing more. What the voice coil can dissipate as heat is a separate ceiling set by the driver, not by the box — Ground Zero rate this one at 1000 W RMS, and that is the number that binds first here: heat stops you before travel does, so treat 1000 W as the ceiling and the travel figures above as headroom. Final wired impedance, amplifier output and how long you hold the level are all electrical questions this graph does not answer.

From the shop floor

Installer's take

I built this box on Ground Zero's own published Fs, Qts, and Vas for the GZRW 12XSPL: 31.80 Hz, 0.6840, and 27.20 litres, backed by a 0.7580 Qes and a 7.0280 Qms. It lands at 1.445 cubic feet net, vented at 35.5 Hz, and the model gives back F3 at 29.5 Hz with 4.43 dB of ripple. Ground Zero publishes no vented number of their own for this driver, so there is nothing to check the curve against.

Ground Zero publishes no cone area for this driver. The 521.3 square centimetre Sd behind this alignment, the tuning, the port sizing, and the velocity math, is estimated rather than measured or stated by Ground Zero. Ground Zero also publishes no driver displacement; the 0.111 cubic foot figure I used is estimated too, and it only touches the gross volume number, not the tuning or the port.

Ground Zero calls its excursion spec Max. Excursion and never says what it is measured to. For the GZRW 12XSPL the manual gives a peak-to-peak figure, and I halved it to the 22.5 mm one-way number this box is built around. That halving is the reason this model gets a cabinet at all; most of the rest of the Ground Zero line states no basis for its excursion figure and stays off the bench.

Ground Zero publishes no mounting hole locations for this driver, so I am not pressing the threaded inserts before it ships. The insert kit rides loose in the box; set them at install once the driver is in hand.

Wire the single SVC coil to whatever impedance your amplifier is rated for.

Ground Zero publishes no mounting hole locations for the GZRW 12XSPL, so the inserts are not in the baffle when the box arrives. The insert kit is in the box: set the inserts where the woofer's own holes fall, with the drill bit and the 2.5 inch allen-head screws in the kit, and lay the gasket tape before the woofer goes down.

The Performance Optimized wedge is the smaller and cheaper box, and I try it first for every driver. The GZRW 12XSPL does not fit it, so this is the box.

It ships dry. Do not add polyfill to a ported box. Set your subsonic filter at 30 Hz.

Before you order

Questions

Why is this enclosure tuned to 35.5 Hz?

A 0.6840 Qts on 27.20 litres of Vas, backed by a 0.7580 Qes and a 7.0280 Qms, is a compliant motor that wants air, and 35.5 Hz brings F3 to 29.5 Hz on 4.43 dB of ripple. At the driver's rated 1000 W the port runs 13.6 metres per second through the mouth at 1200 W, the reference point the velocity check is measured against. The 521.3 square centimetre Sd behind this solve is not a Ground Zero figure: Ground Zero publishes no cone area for the GZRW 12XSPL, so the number is estimated. Tuning is chosen for in-car response rather than an anechoic curve: a vehicle adds roughly 12 dB per octave below about 45 Hz, and this tuning is where that sum comes out flattest across 25 to 60 Hz.

Why is this a Professional build and not a Performance Optimized box?

Every driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The GZRW 12XSPL did not clear the channel 25.1 m/s over 0.55 x core 44.9 gate there: the nearest wedge that fits is 27.5 by 9.75 by 15.39 inches with a 24.7 square inch port, and no tuning, width or depth inside that envelope passes. The slot on this box reaches 29.0 square inches. An under-ported box does not fail quietly. Air speed at the mouth rises with power; past the chuff line the flow turns turbulent and the port is audible on every note. The turbulence also chokes the port, so the box behaves as if it were tuned higher than it is, loses output near tuning, and lets the cone travel further below tuning than the design allows. This chassis is a full-size front-firing box on a 2.25 inch baffle built from three 3/4 inch layers with the woofer flush-mounted in the outer layer, a Ground Zero logo acrylic, and a port and excursion budget checked at 1200 W. It carries a 2 year warranty against 1.

Threaded inserts or a kit?

Ground Zero does not publish the mounting hole locations for the GZRW 12XSPL, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer; one kit serves one woofer. A dual cabinet ships two kits.

Do I need a subsonic filter?

Yes, at 28 Hz, 24 dB per octave. Below tuning a vented box stops loading the cone and excursion runs away toward DC. With the filter in place this cabinet puts the Ground Zero GZRW 12XSPL at 45 percent of its usable travel at 1200 W.

Would a sealed box be better for me?

Not one we can show you. We do not build a sealed enclosure for the Ground Zero GZRW 12XSPL and Ground Zero publish no sealed volume for it, so the Performance Graphs tab carries no ported-versus-sealed chart: the only sealed box left to plot would be this cabinet stuffed and sealed, which nobody would build, and a comparison against it would tell you nothing you could buy. What a vented box gives up is the region below tuning, where the cone unloads and the 28 Hz subsonic filter takes over; around 35.5 Hz the vent carries the load and cone travel drops to its minimum, which no sealed alignment can do.

How does the front port work?

It is a vertical slot beside the woofer, the full height of the cavity, 2.00 inches wide and 29.0 square inches. It runs 6.25 inches to the back wall and turns once along it for 22.03 inches; the fold costs about 1.5 Hz and the port is cut for it. The channel runs at 21.8 metres per second at 1200 W, 46 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 13.6 metres per second against the 17 metres per second threshold where a slot starts to chuff.

What does the price cover, and how does it ship?

54 lb, 32.00" W x 16.00" H x 12.00" D external. It ships as a UPS parcel; the price includes shipping in the 48 states. Every Professional cabinet is priced the same way, by its size: this one is 3.56 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 54 lb parcel and checkout adds nothing. Do not add polyfill; it ships dry on purpose.

Is the GZRW 12XSPL included?

No. This is an enclosure only, cut for the Ground Zero GZRW 12XSPL specifically: the 11.340 inch cutout, the 6.540 inch mounting depth allowance and the 1.44 cubic foot alignment all come from Ground Zero's published parameters. It fits both coil versions; the alignment published here is the SVC. Bring your own driver.

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