Sky High Car Audio FXB-15 D2
15″ subwoofer · dual 2 Ω · 1,500 W RMS
The Sky High Car Audio FXB-15 D2 is a 15″ subwoofer. With Qts 0.70 and EBP 38 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| Bass character (Qtc) | Boomy, with a bump · 0.96 |
|---|---|
| Fc | 40 Hz |
| F3 (−3 dB, no cabin gain) | 34 Hz |
| Example box (outside) | 31 1/2″ × 17 11/16″ × 12 1/8″ |
Ported
deeper, louder| Tuning (Fb) | 32 Hz |
|---|---|
| Port | slot 2 3/16 × 16 5/16″, 40 7/8″ long |
| Port velocity at 1,500 W | 61 ft/s |
| F3 (−3 dB, no cabin gain) | 31 Hz |
| Example box (outside) | 24 3/4″ × 17 11/16″ × 16 1/8″ |
Deeper: 4.87 ft³ (138 L) tuned to 28 Hz, 31 1/2″ × 17 11/16″ × 24 15/16″ outside — a bigger box with flatter deep bass. Open in the calculator
Projects with this subwoofer
Boxes that users designed and published: plans, cut sheet and response graph.
Thiele/Small parameters
| Size | 15″ |
|---|---|
| Voice coils | dual 2 Ω |
| RMS power | 1,500 W |
| Fs | 29.5 Hz |
| Qts | 0.70 |
| Qes | 0.78 |
| Qms | 7.13 |
| Vas | 2.44 ft³ |
| Re (one coil) | 1.9 Ω |
|---|---|
| Sd | 126.3 in² |
| Xmax | 1.18″ |
| Vd | 149.1 in³ calc. |
| Mms | 395 g calc. |
| BL | 13.4 T·m calc. |
| EBP | 38 — suits sealed calc. |
| Sensitivity, 1 W / 1 m | 85.6 dB calc. |
Mounting dimensions
| Cutout diameter | 13 3/4″ |
|---|---|
| Mounting depth | 9″ |
| Overall diameter | 15 1/2″ |
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.
- Excursion — behind the third row sealed and ported box
Cone area (Sd) calculated from Fs, Vas and Mms: 126.3 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
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-15 D2 | dual 2 Ω | 1.9 Ω | 0.78 | 2.44 ft³ | 2.86 ft³ | 2.01 ft³ · 32 Hz |
| Sky High Car Audio FXB-15 D4 | dual 4 Ω | 3.2 Ω | 0.83 | 2.31 ft³ | 2.86 ft³ | 2.01 ft³ · 32 Hz |
Other Sky High Car Audio 15″ models
- Sky High Car Audio BMX-15 D1 15″ · dual 1 Ω
- Sky High Car Audio BMX-15 D2 15″ · dual 2 Ω
- Sky High Car Audio FE-15 D2 15″ · dual 2 Ω
- Sky High Car Audio FE-15 D4 15″ · dual 4 Ω
- Sky High Car Audio FEX-15 D2 15″ · dual 2 Ω
- Sky High Car Audio FEX-15 D4 15″ · dual 4 Ω
- Sky High Car Audio FMX-15 D1 15″ · dual 1 Ω
- Sky High Car Audio FMX-15 D2 15″ · dual 2 Ω
- Sky High Car Audio FXXL-15 D1 15″ · dual 1 Ω
- Sky High Car Audio FXXL-15 D2 15″ · dual 2 Ω
Similar 15″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Cerwin-Vega Mobile VMAX154 (VMAX 15" DVC 4ohm) 2.83 ft³ sealed · 1.80 ft³ ported
- Memphis Car Audio M71512 (M7 15", 1ohm setting) 3.11 ft³ sealed · 2.30 ft³ ported
- URAL AS-D15.3TD2 (2+2) 2.83 ft³ sealed · 2.22 ft³ ported
- URAL AS-D15.3TD4 (4+4) 2.83 ft³ sealed · 2.22 ft³ ported
- RE Audio SEX15 D4 v2 2.90 ft³ sealed · 2.01 ft³ ported
- Diamond CM315D4 2.79 ft³ sealed · 2.33 ft³ ported
FAQ
What box does the Sky High Car Audio FXB-15 D2 need?
Recommended net volume: 2.86 ft³ sealed, 2.01 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-15 D2 Thiele/Small specs?
Fs 29.5 Hz, Qts 0.70, Vas 2.44 ft³, Xmax 1.18″, Sd 126.3 in².
What is the Sky High Car Audio FXB-15 D2 mounting depth?
Mounting depth is 9″, cutout diameter 13 3/4″. 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-15 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-15 D2 better sealed or ported?
EBP 38: a sealed box (2.86 ft³) suits it best — tight bass in a compact enclosure. Ported is possible (2.01 ft³, tuned to 32 Hz) but larger.
What port does the Sky High Car Audio FXB-15 D2 need?
For the 2.01 ft³ ported box tuned to 32 Hz: slot 2 3/16 × 16 5/16″, 40 7/8″ long, area 35.3 in²; or a round port Ø6 11/16″, ≈ 40 7/8″ long. Port air speed at 1,500 W: 61 ft/s.
What box do two Sky High Car Audio FXB-15 D2 subs need?
Two subs need twice the volume: 5.72 ft³ sealed, or 4.03 ft³ ported at the same 32 Hz tuning with twice the port area. One shared chamber or one per sub — whatever fits your vehicle.