Fi Audio SSD NEO 18 D1
18″ subwoofer · dual 1 Ω · 1,500 W RMS
The Fi Audio SSD NEO 18 D1 is a 18″ subwoofer. With Qts 0.53 and EBP 63 it works both sealed and ported: sealed is tighter and smaller, ported is deeper and louder.
| Source | web.archive.org · 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 | 54 Hz |
| F3 (−3 dB, no cabin gain) | 51 Hz |
| Example box (outside) | 31 1/2″ × 20 7/8″ × 13″ |
Ported
deeper, louder| Tuning (Fb) | 34 Hz |
|---|---|
| Port | slot 2 3/4 × 19 7/16″, 27 3/8″ long |
| Port velocity at 1,500 W | 61 ft/s |
| F3 (−3 dB, no cabin gain) | 37 Hz |
| Example box (outside) | 31 1/2″ × 20 7/8″ × 16 3/16″ |
Deeper: 7.27 ft³ (206 L) tuned to 34 Hz, 31 1/2″ × 20 7/8″ × 27 1/8″ 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 1 Ω |
| RMS power | 1,500 W |
| Fs | 35.7 Hz |
| Qts | 0.53 |
| Qes | 0.57 |
| Qms | 7.73 |
| Vas | 4.63 ft³ |
| Re (one coil) | 0.7 Ω |
|---|---|
| Sd | 187.6 in² |
| Xmax | 1.10″ |
| Vd | 206.7 in³ calc. |
| Mms | 315 g calc. |
| BL | 9.3 T·m calc. |
| EBP | 63 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 92.2 dB calc. |
Mounting dimensions
| Cutout diameter | 16 3/4″ |
|---|---|
| Mounting depth | 10 1/2″ |
| Overall diameter | 18 1/2″ |
“≈” 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
- web.archive.org/web/20190920055738/https://ficaraudio.com/product/ssd-neo-ssd10/
- web.archive.org/web/20190821134134/https://ficaraudio.com/product/ssd-neo-12/
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 |
|---|---|---|---|---|---|---|
| Fi Audio SSD NEO 18 D1 | dual 1 Ω | 0.7 Ω | 0.57 | 4.63 ft³ | 3.64 ft³ | 3.71 ft³ · 34 Hz |
| Fi Audio SSD NEO 18 D2 | dual 2 Ω | 1.4 Ω | 0.57 | 4.63 ft³ | 3.64 ft³ | 3.71 ft³ · 34 Hz |
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.
- DC Audio XL-SPL 18 D1 4.03 ft³ sealed · 4.06 ft³ ported
- DC Audio XL-SPL 18 D2 4.03 ft³ sealed · 4.06 ft³ ported
- DC Audio XL-SPL 18 D4 4.03 ft³ sealed · 4.06 ft³ ported
- JBL Selenium 18SWT3000 3.81 ft³ sealed · 3.57 ft³ ported
- Incriminator Audio Death Penalty 18 D1 2.37 ft³ sealed · 3.46 ft³ ported
- Ground Zero GZNW 18XSPL (2x1 Ohm) 4.27 ft³ sealed · 3.96 ft³ ported
FAQ
What box does the Fi Audio SSD NEO 18 D1 need?
Recommended net volume: 3.64 ft³ sealed, 3.71 ft³ ported tuned to 34 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 SSD NEO 18 D1 Thiele/Small specs?
Fs 35.7 Hz, Qts 0.53, Vas 4.63 ft³, Xmax 1.10″, Sd 187.6 in².
What is the Fi Audio SSD NEO 18 D1 mounting depth?
Mounting depth is 10 1/2″, cutout diameter 16 3/4″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Fi Audio SSD NEO 18 D1 handle and how do I wire it?
RMS power rating: 1,500 W. Dual 1 Ω voice coils: series gives 2 Ω, parallel gives 0.5 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.
Is the Fi Audio SSD NEO 18 D1 better sealed or ported?
EBP 63: both work — sealed 3.64 ft³ is tighter and smaller, ported 3.71 ft³ tuned to 34 Hz is deeper and louder.
What port does the Fi Audio SSD NEO 18 D1 need?
For the 3.71 ft³ ported box tuned to 34 Hz: slot 2 3/4 × 19 7/16″, 27 3/8″ long, area 53.6 in²; or a round port Ø8 1/4″, ≈ 27 3/8″ long. Port air speed at 1,500 W: 61 ft/s.
What box do two Fi Audio SSD NEO 18 D1 subs need?
Two subs need twice the volume: 7.27 ft³ sealed, or 7.42 ft³ ported at the same 34 Hz tuning with twice the port area. One shared chamber or one per sub — whatever fits your vehicle.