Sky High Car Audio FXB-12 D2

12″ subwoofer · dual 2 Ω · 1,500 W RMS

28.8 HzFs, resonance

0.60Qts

0.98 ft³Vas

1.18″Xmax

1,500 WRMS

The Sky High Car Audio FXB-12 D2 is a 12″ subwoofer. With Qts 0.60 and EBP 44 it suits a sealed box: tight bass in a small enclosure; a ported box would need a lot of volume. Long excursion (Xmax 1.18″) — built for loud music and high power.

Source	skyhighcaraudio.com · manufacturer data
Checked against source	October 2026
Thiele/Small parameters	complete
Mounting dimensions	3 of 4 — missing: magnet diameter; the designer will use an estimate

Recommended box

For a sedan, one sub, 1,500 W. It’s the same math as the designer’s step-by-step mode, where you can fit the box to your space, vehicle and amp and get plans, a cut sheet and DXF.

Sealed

smaller, tighter

1.24 ft³ (35 L)

Net volume

Bass character (Qtc)	Tight and punchy · 0.80
Fc	39 Hz
F3 (−3 dB, no cabin gain)	36 Hz
Example box (outside)	14 3/16″ × 14 3/16″ × 15 11/16″

Open sealed box in designer

Ported

deeper, louder

1.31 ft³ (37 L)

Net volume

Tuning (Fb)	32 Hz
Port	slot 1 9/16 × 14 5/16″, 41 3/16″ long
Port velocity at 1,500 W	95 ft/s
F3 (−3 dB, no cabin gain)	28 Hz
Example box (outside)	20 5/16″ × 15 3/4″ × 15 3/16″

At 1,500 W this example’s port will be noisy: air speed 95 ft/s, while the limit is 82 ft/s. It stays quiet up to about 1,100 W. Full power needs a port of at least 26 in², which means a bigger box than this example — size it in the designer.

Open ported box in designer

Deeper: 3.18 ft³ (90 L) tuned to 25 Hz, 31 1/2″ × 15 3/4″ × 23 1/8″ outside — a bigger box with flatter deep bass. Open in the calculator

Where to buy Amazon

Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Size	12″
Voice coils	dual 2 Ω
RMS power	1,500 W
Fs	28.8 Hz
Qts	0.60
Qes	0.66
Qms	6.44
Vas	0.98 ft³

Re (one coil)	1.9 Ω
Sd	81.8 in²
Xmax	1.18″
Vd	96.7 in³ calc.
Mms	434 g calc.
BL	15 T·m calc.
EBP	44 — suits sealed calc.
Sensitivity, 1 W / 1 m	82 dB calc.

Mounting dimensions

Cutout diameter	11 1/8″
Mounting depth	7 15/16″
Overall diameter	12 13/16″

Where it fits in a vehicle

Spots from our vehicle guides where the cutout, mounting depth and recommended box fit. The spot sizes are approximate — measure your own vehicle.

Bronco 4-door — behind the rear seat sealed and ported box
Wrangler 4-door, hard top — behind the rear seat sealed and ported box
Wrangler 4-door, soft top — behind the rear seat sealed and ported box
Silverado / Sierra Crew Cab — under the rear seat sealed and ported box
FJ Cruiser — behind the rear seat sealed and ported box
El Camino 1978–87 — behind the seat sealed and ported box
Cherokee XJ — cargo area, spare moved out sealed and ported box
Excursion — behind the third row sealed and ported box
Mustang 2015–2023 coupe — trunk sealed and ported box
Challenger / Charger — trunk sealed and ported box
Club Car Precedent — under the rear seat sealed and ported box

Cone area (Sd) calculated from Fs, Vas and Mms: 81.8 in².

“≈” means the value isn’t in the spec sheet and a typical value for the size is used; “calc.” means it’s calculated from the published parameters. Check the manufacturer’s spec sheet before you build.

Data sources

skyhighcaraudio.com/sky-high-car-audio-fxb-series-12-subwoofer/

Voice coil versions

The same sub with different voice coils: the parameters are nearly the same — pick by your amp and wiring.

Model	Voice coils	Re	Qes	Vas	Sealed	Ported
Sky High Car Audio FXB-12 D2	dual 2 Ω	1.9 Ω	0.66	0.98 ft³	1.24 ft³	1.31 ft³ · 32 Hz
Sky High Car Audio FXB-12 D4	dual 4 Ω	3.2 Ω	0.76	1.02 ft³	1.87 ft³	1.31 ft³ · 34 Hz

Other Sky High Car Audio 12″ models

Sky High Car Audio BMX-12 D1 12″ · dual 1 Ω
Sky High Car Audio BMX-12 D2 12″ · dual 2 Ω
Sky High Car Audio FE-12 D2 12″ · dual 2 Ω
Sky High Car Audio FE-12 D4 12″ · dual 4 Ω
Sky High Car Audio FEX-12 D2 12″ · dual 2 Ω
Sky High Car Audio FEX-12 D4 12″ · dual 4 Ω
Sky High Car Audio FMX-12 D1 12″ · dual 1 Ω
Sky High Car Audio FMX-12 D2 12″ · dual 2 Ω
Sky High Car Audio FXXL-12 D1 12″ · dual 1 Ω
Sky High Car Audio FXXL-12 D2 12″ · dual 2 Ω

Similar 12″ subwoofers from other brands

Close in Fs, Qts and Vas — a box of similar volume will suit them.

DL Audio Phoenix Black Bass 12 (2+2) 1.24 ft³ sealed · 1.20 ft³ ported
CT Sounds OZONE-12 D2 1.27 ft³ sealed · 1.17 ft³ ported
Vibe Audio BlackAir 12 D2 (BLACKAIR12D2-V7) 0.99 ft³ sealed · 1.17 ft³ ported
Pride HP Lite 12 D1.8 0.99 ft³ sealed · 1.13 ft³ ported
DC Audio Level 2 M3 12 D2 1.34 ft³ sealed · 1.20 ft³ ported
DC Audio Level 2 M3 12 D4 1.34 ft³ sealed · 1.20 ft³ ported

FAQ

What box does the Sky High Car Audio FXB-12 D2 need?

Recommended net volume: 1.24 ft³ sealed, 1.31 ft³ ported tuned to 32 Hz — for one sub in a sedan at 1,500 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the Sky High Car Audio FXB-12 D2 Thiele/Small specs?

Fs 28.8 Hz, Qts 0.60, Vas 0.98 ft³, Xmax 1.18″, Sd 81.8 in².

What is the Sky High Car Audio FXB-12 D2 mounting depth?

Mounting depth is 7 15/16″, cutout diameter 11 1/8″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the Sky High Car Audio FXB-12 D2 handle and how do I wire it?

RMS power rating: 1,500 W. Dual 2 Ω voice coils: series gives 4 Ω, parallel gives 1 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.

Is the Sky High Car Audio FXB-12 D2 better sealed or ported?

EBP 44: a sealed box (1.24 ft³) suits it best — tight bass in a compact enclosure. Ported is possible (1.31 ft³, tuned to 32 Hz) but larger.

What port does the Sky High Car Audio FXB-12 D2 need?

For the 1.31 ft³ ported box tuned to 32 Hz: slot 1 9/16 × 14 5/16″, 41 3/16″ long, area 22.6 in²; or a round port Ø5 3/8″, ≈ 41 3/16″ long. Port air speed at 1,500 W: 95 ft/s.

What box do two Sky High Car Audio FXB-12 D2 subs need?

Two subs need twice the volume: 2.47 ft³ sealed, or 2.61 ft³ ported at the same 32 Hz tuning with twice the port area. One shared chamber or one per sub — whatever fits your vehicle.