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Performance Optimized · Datasheet

Performance Optimized Down Fire Wide Sealed Dual 12" Enclosure NVX VCW12v3 · Dual 12" Sealed enclosure

Net volume
0.857 cu ft after displacement
External dimensions
41 in W × 9.625 in in the down fire position H × 14 in D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
  • Alignment: 0.857 cu ft net per chamber, 1.714 cu ft total. VCW122v3 (D2): Qtc 0.665, Fc 41.7 Hz, F3 44.4 Hz; VCW124v3 (D4): Qtc 0.665, Fc 41.7 Hz, F3 44.4 Hz per driver
  • Down Fire Wide: 41"W x 14"D x 9.625"H in down fire position, excludes standoffs, square corners
  • Versus the standard 30 x 15: 11.82 in tall and 0.85 cu ft net per chamber there, 9.625 in tall and 0.857 cu ft net here
  • Chambers: Two fully separate sealed chambers, 3/4" MDF full divider, one shared side-mounted terminal cup
  • Drivers: Pair of NVX VCW12v3 (VCW122v3 D2 or VCW124v3 D4), 1200 W RMS each, 23 mm Xmax, 6.85 in mounting depth
  • Standoffs: Included, 1.75 in, shipped uninstalled. Installed height 11.375 in

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Down Fire Wide
Compatible DriverNVX VCW12v3, pair required. Direct fit
Enclosure TypeSealed, dual driver, down fire, floor coupled
Intended FitmentSpaces where height or depth is the limit and 41 in of run is available
Chamber ConfigurationTwo fully separate chambers, full divider, single shared side-mounted terminal cup
External Width41 in
External Depth14 in
External Height9.625 in in the down fire position, excludes standoffs
Installed Height11.375 in including the 1.75 in standoffs
Internal Volume, Gross2.05 cu ft total
Per-Chamber Net Volume0.857 cu ft after displacement
Total Net Volume1.714 cu ft
Height Set ByAirspace; 2.025 in clearance above the motor
Alignment, VCW122v3 (D2) per chamberQtc 0.665, Fc 41.7 Hz, F3 44.4 Hz anechoic
Alignment, VCW124v3 (D4) per chamberQtc 0.665, Fc 41.7 Hz, F3 44.4 Hz anechoic
Comparison, Standard 30 x 1511.82 in tall, 0.85 cu ft net per chamber. Wide format is 9.625 in tall with 0.857 cu ft net per chamber
Woofer Opening11.18 in, two, NVX's published cutout
Frame Outer Diameter12.64 in, NVX published
Bolt Circle11.63 in, NVX published; threaded inserts pre-installed
Driver Displacement0.150 cu ft, NVX published
VCW122v3 (D2) Fs / Qts / Qes / Qms / Vas25.05 Hz / 0.400 / 0.434 / 5.12 / 42.90 L
VCW124v3 (D4) Fs / Qts / Qes / Qms / Vas25.05 Hz / 0.400 / 0.434 / 5.12 / 42.90 L (NVX product page column)
Driver Sd530 cm2, published by NVX
Xmax23 mm one way, NVX spec
Driver Power Handling1200 W RMS per driver, NVX spec
Floor Slot0.75 times the cone area at the 1.75 in standoff
Parameter SourceNVX VCW122v3 / VCW124v3 owner's manual and nvx.com product pages
MaterialLangboard Elite 3/4 in MDF
ConstructionShopSabre CNC, V-groove and dado joinery
Panel Thickness0.75 in
Front Baffle1.5 in double baffle, outer layer machined as a flush recess
Internal BracingFull-height 3/4 in bonded divider
Corner ProfileSquare, Down Fire series standard
Driver MountingThreaded inserts pressed on NVX's published 11.63 inch bolt circle, stainless machine screws included
Terminal CupOne Proline X ABS and carbon fiber composite, side mounted, pre-wired 12 gauge OFC to both driver positions in parallel
StandoffsIncluded, 1.75 in, shipped uninstalled
DampingLight polyfill wall lining in both chambers, does not alter acoustic volume
CarpetPlush Black
Bundle OptionsEnclosure only, bring your own pair of NVX VCW12v3
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
0.857
cu ft per chamber
System Qtc
0.67
sealed
Half power
44.4
Hz · F3
Xmax at
1441
W RMS · no filter
With 25 Hz subsonic
2209
W RMS · +53%
Amplifier
1200
W RMS recommended
This enclosure holds 0.857 cu ft net per chamber. In it the NVX VCW12v3 runs a system Qtc of 0.67 with half power at 44.4 Hz, and the cone reaches its 23.0 mm travel limit at 1441 W, 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 2209 W — +769 W, or 53 percent more power for the same 23.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 57.7
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D2 57.7 D4 57.7
D2 · EBP 57.7D4 · EBP 57.7
At 57.7 the VCW12v3 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

0.857 cu ft against a 42.9 L Vas.

α = Vas ÷ Vb = 1.77  ·  Fc = Fs√(α+1) = 42 Hz  ·  Qtc = 0.67
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D2 · Qtc 0.67, Fc 42 Hz, F3 44.4 HzD4 · Qtc 0.67, Fc 42 Hz, F3 44.4 Hz
The box lifts resonance from 25.1 Hz free-air to 42 Hz and half power lands at 44.4 Hz, anechoic, before any cabin gain. Figures are NVX’s published VCW12v3 parameters from its owner’s manual and product pages, displacement included (0.150 cubic feet). One cabinet serves both coils; both are plotted. Each chamber holds 0.857 cubic feet, so these figures are 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 23.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 1441 W unfiltered  →  2209 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 23.0 mm 1441 W reaches Xmax here
D2 · 1441 W, no filterD4 · 1441 W, no filterD2 · 2209 W with subsonic at 25 Hz, 24 dB/octD4 · 2209 W with subsonic at 25 Hz, 24 dB/octXmax 23.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 23.0 mm. Unfiltered that is 1441 W, 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 2209 W before hitting the same 23.0 mm. That is 53 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs25.05Hzfree-air resonance
Qts0.400 / 0.400D2 / D4
Vas42.90 / 42.90Lequivalent compliance
Sd530.0cm²effective piston area
Xmax23mmone-way linear travel
Pe1200Wcontinuous RMS
SPL83.8dB1 W / 1 m, derived from T/S

Driver parameters as published by NVX VCW12v3 owner’s manual. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

Same pair of VCW12v3 as the standard 30 by 15 box, laid out 41 by 14. One inch shallower, 11 inches longer, and 9.625 inches tall against 11.82. Measure all three dimensions before choosing between them.

Airspace set the height here, 0.857 cubic feet net per chamber, with 2.025 inches clear above the motor.

Alignment: VCW122v3 (D2) at Qtc 0.665, F3 44.4 Hz; VCW124v3 (D4) at Qtc 0.665, F3 44.4 Hz.

Cut is 11.18, NVX's own figure, and the inserts are already pressed on their 11.63 bolt circle. Floor slot is 0.75 times the cone area at the 1.75 standoff; taller feet help if the floor allows. Leave the polyfill as it is and run it at 1200 watts per driver or under.

Before you order

Questions

Why is this cabinet 41 inches wide instead of 30?

Because it trades length for depth and height. The standard dual Down Fire platform is 30 wide by 15 deep; this one is 14 deep, 1 inch shallower, and runs 41 inches long to put the airspace along the length instead.

That lets it stand 9.625 inches tall against 11.82 for the standard box. A 12 inch frame needs about 13 inches of baffle, so 14 is as shallow as a 12 can go. If you have 41 inches of run and height or depth is your limit, this is the shape that works.

How does this compare to the standard 30 x 15 dual VCW12v3 enclosure?

The standard box is 30 by 15 by 11.82 inches and holds 0.85 cubic feet net per chamber. This one is 41 by 14 by 9.625 inches and holds 0.857 cubic feet net per chamber.

Choose the standard box when length is limited. Choose this one when height or depth is the limit and you have 41 inches of run.

What alignment does this enclosure produce?

At 0.857 cubic feet net per chamber the result is VCW122v3 (D2): Qtc 0.665, Fc 41.7 Hz, F3 44.4 Hz; VCW124v3 (D4): Qtc 0.665, Fc 41.7 Hz, F3 44.4 Hz, calculated from the driver's own published Thiele-Small parameters.

That is a little under the 0.707 maximally flat reference, so the rolloff is gentle rather than peaked. The figures are anechoic; in a car, cabin gain adds real output below 50 Hz, so in-vehicle response runs deeper.

How much power should I run, and how do I wire these subwoofers?

NVX rates the VCW12v3 at 1200 watts RMS, 2400 watts RMS combined. A pair of VCW122v3 (D2) drivers can land on 0.5 ohm with all four coils in parallel, 2 ohms as series pairs in parallel, or 8 ohms all in series. A pair of VCW124v3 (D4) drivers can land on 1 ohm with all four coils in parallel, 4 ohms as series pairs in parallel, or 16 ohms all in series. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for; series wiring is the safe default. Confirm the load against your amplifier's minimum stable impedance before powering the system.

How tall is this once the standoffs are on?

The cabinet is 9.625 inches tall measured in the down fire position, excluding standoffs. The standoffs hold 1.75 inches under the baffle, so plan your space around 11.375 inches installed.

The standoffs ship uninstalled, so you can place them to suit your floor, or leave them off and run the cabinet front firing or up firing.

Where is the terminal cup located on a down fire enclosure?

Side mounted, and there is one cup serving both chambers. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup regardless of alignment, whether standard, wedge, or down fire. On this cabinet that keeps the connection accessible with the enclosure installed, since the baffles face the floor. The cup is our Proline X ABS and carbon fiber composite unit with stainless hardware, copper ring terminals, and pre-wired 12 gauge OFC.

How is this enclosure built?

V-groove and dado joinery, CNC cut on ShopSabre routers from Langboard Elite MDF, with square corners as the Down Fire standard. Every panel joint is a machined interlocking groove that locks before adhesive is applied, which keeps the cabinet airtight under sustained pressure cycling.

The 1.5 inch double baffle has its outer layer machined as a flush recess so the driver bolts to the inner layer, and a full-height bonded 3/4 inch divider separates the chambers and ties the walls together across the 41 inch span. Polyfill is installed as a light wall lining; do not add more, since packing a sealed box makes it act larger and moves the alignment. Assembled and inspected in Tullahoma, Tennessee.

Is the pair of NVX VCW12v3 included with this enclosure?

No. This listing is for the enclosure only. Bring your own pair of NVX VCW12v3. The cutout and cabinet height are cut direct fit for both positions. Threaded inserts are pressed on NVX's published 11.63 inch bolt circle and stainless machine screws are included.

Same series, same size

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