Fi Audio Xv5 18 D2
18″ subwoofer · dual 2 Ω · 1,500 W RMS
| Source | ficaraudio.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) | Tight and punchy · 0.80 |
|---|---|
| Fc | 55 Hz |
| F3 (−3 dB, no cabin gain) | 52 Hz |
| Example box (outside) | 20 1/16″ × 20 1/16″ × 12 3/8″ |
Ported
deeper, louder| Tuning (Fb) | 32 Hz |
|---|---|
| Port | slot 2 3/4 × 19 7/16″, 31 5/16″ long |
| Port velocity at 1,500 W | 64 ft/s |
| F3 (−3 dB, no cabin gain) | 32 Hz |
| Example box (outside) | 31 1/2″ × 20 7/8″ × 16 3/4″ |
Deeper: 6.25 ft³ (177 L) tuned to 29 Hz, 31 1/2″ × 20 7/8″ × 25 3/8″ 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 | 18″ |
|---|---|
| Voice coils | dual 2 Ω |
| RMS power | 1,500 W |
| Fs | 29.5 Hz |
| Qts | 0.43 |
| Qes | 0.469 |
| Qms | 5.19 |
| Vas | 4.69 ft³ |
| Re (one coil) | 1.86 Ω |
|---|---|
| Sd | 176.7 in² |
| Xmax | 1.14″ |
| Vd | 201.8 in³ calc. |
| Mms | 404 g calc. |
| BL | 17.2 T·m calc. |
| EBP | 63 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 90.6 dB calc. |
Mounting dimensions
| Cutout diameter | 16 7/8″ |
|---|---|
| Mounting depth | 9 15/16″ |
| Overall diameter | 18 1/2″ |
Judging by its value, the published Re is for both coils in series — converted to per coil.
“≈” 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
Other Fi Audio 18″ models
- Fi Audio BL-NEO 18 D1 18″ · dual 1 Ω
- Fi Audio BL-NEO 18 D2 18″ · dual 2 Ω
- Fi Audio BL18v3 D1 18″ · dual 1 Ω
- Fi Audio BL18v3 D2 18″ · dual 2 Ω
- Fi Audio BL18v3.1 D1 18″ · dual 1 Ω
- Fi Audio BL18v3.1 D2 18″ · dual 2 Ω
- Fi Audio BTL-NEO18 D1 18″ · dual 1 Ω
- Fi Audio BTL-NEO18 D2 18″ · dual 2 Ω
- Fi Audio BTL3 18 D1 18″ · dual 1 Ω
- Fi Audio BTL3 18 D2 18″ · dual 2 Ω
- Fi Audio BTL4 18 D1 18″ · dual 1 Ω
- Fi Audio BTL4 18 D2 18″ · dual 2 Ω
Similar 18″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Sundown Audio Xv3-18 D1 2.01 ft³ sealed · 6.99 ft³ ported
- SPL Dynamics SPL-460D1A 1.92 ft³ sealed · 5.65 ft³ ported
- Sundown Audio Uv1-18 D4 1.80 ft³ sealed · 5.90 ft³ ported
- Audioque HDC318-A D1 1.70 ft³ sealed · 3.07 ft³ ported
- Sundown Audio Xv2-18 D4 2.90 ft³ sealed · 3.88 ft³ ported
- Magnum MEW 18-22DC 2.14 ft³ sealed · 3.14 ft³ ported
FAQ
What box does the Fi Audio Xv5 18 D2 need?
Recommended net volume: 1.92 ft³ sealed, 3.74 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 Fi Audio Xv5 18 D2 Thiele/Small specs?
Fs 29.5 Hz, Qts 0.43, Vas 4.69 ft³, Xmax 1.14″, Sd 176.7 in².
What is the Fi Audio Xv5 18 D2 mounting depth?
Mounting depth is 9 15/16″, cutout diameter 16 7/8″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Fi Audio Xv5 18 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.