Fi Audio X10 S2
10″ subwoofer · 2 Ω · 400 W RMS
The Fi Audio X10 S2 is a 10″ subwoofer. With Qts 0.41 and EBP 83 it works both sealed and ported: sealed is tighter and smaller, ported is deeper and louder. Long excursion (Xmax 0.71″) — built for loud music and high power.
| 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, 400 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) | Flat and accurate · 0.68 |
|---|---|
| Fc | 61 Hz |
| F3 (−3 dB, no cabin gain) | 67 Hz |
| Example box (outside) | 12 5/8″ × 12 5/8″ × 8 1/8″ |
Ported
deeper, louder| Tuning (Fb) | 43 Hz |
|---|---|
| Port | 2 round ports Ø2 1/2″, 16 11/16″ long |
| Port velocity at 400 W | 105 ft/s |
| F3 (−3 dB, no cabin gain) | 40 Hz |
| Example box (outside) | 18 9/16″ × 15 3/4″ × 8 1/4″ |
At 400 W this example’s port will be noisy: air speed 105 ft/s, while the limit is 82 ft/s. It stays quiet up to about 240 W. Full power needs a port of at least 12.8 in², which means a bigger box than this example — size it in the designer.
Open ported box in designerDeeper: 0.92 ft³ (26 L) tuned to 37 Hz, 16 5/8″ × 15 3/4″ × 13″ 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 | 10″ |
|---|---|
| Voice coils | 2 Ω |
| RMS power | 400 W |
| Fs | 36.4 Hz |
| Qts | 0.41 |
| Qes | 0.44 |
| Qms | 5.16 |
| Vas | 0.78 ft³ |
| Re | 1.9 Ω |
|---|---|
| Sd | 48.1 in² |
| Xmax | 0.71″ |
| Vd | 34.1 in³ calc. |
| Mms | 118 g calc. |
| BL | 10.8 T·m calc. |
| EBP | 83 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 85.8 dB calc. |
Mounting dimensions
| Cutout diameter | 9 1/4″ |
|---|---|
| Mounting depth | 5 3/4″ |
| Overall diameter | 11″ |
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.
- F-150 SuperCrew — under the rear seat sealed and ported box
- Ram Crew Cab — under the rear seat sealed and ported box
- Tacoma Double Cab — under the rear seat sealed and ported box
- 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
- Spare tire well sealed box
- Polaris RZR / Ranger — under the seat sealed box
- Can-Am — under the seat sealed 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
- Tesla Model 3 — well under the trunk floor sealed and ported box
- Club Car Precedent — under the rear seat sealed and ported box
“≈” 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 |
|---|---|---|---|---|---|---|
| Fi Audio X10 S2 | 2 Ω | 1.9 Ω | 0.44 | 0.78 ft³ | 0.42 ft³ | 0.78 ft³ · 43 Hz |
| Fi Audio X10 S4 | 4 Ω | 2.9 Ω | 0.44 | 0.78 ft³ | 0.42 ft³ | 0.78 ft³ · 43 Hz |
| Fi Audio X10 D2 | dual 2 Ω | 1.4 Ω | 0.48 | 0.69 ft³ | 0.44 ft³ | 0.78 ft³ · 44 Hz |
| Fi Audio X10 D4 | dual 4 Ω | 2.8 Ω | 0.48 | 0.69 ft³ | 0.44 ft³ | 0.78 ft³ · 44 Hz |
Other Fi Audio 10″ models
- Fi Audio Alpha v1 10 S1 10″ · 1 Ω
- Fi Audio Alpha v1 10 S2 10″ · 2 Ω
- Fi Audio Alpha v1 10 S4 10″ · 4 Ω
- Fi Audio Alpha v2 10 S2 10″ · 2 Ω
- Fi Audio Alpha v2 10 S4 10″ · 4 Ω
- Fi Audio Alpha v2.1 10 S2 10″ · 2 Ω
- Fi Audio Alpha v2.1 10 S4 10″ · 4 Ω
- Fi Audio BL-NEO 10 D1 10″ · dual 1 Ω
- Fi Audio BL-NEO 10 D2 10″ · dual 2 Ω
- Fi Audio BL10 D1 10″ · dual 1 Ω
- Fi Audio BL10 D2 10″ · dual 2 Ω
- Fi Audio BL10v3 D1 10″ · dual 1 Ω
Similar 10″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Elemental Designs E10a 0.46 ft³ sealed · 0.81 ft³ ported
- Kicker CompVX 10" 2-Ohm DVC (50CVX102) 0.49 ft³ sealed · 1.66 ft³ ported
- PowerBass 3XL-101D 0.53 ft³ sealed · 1.66 ft³ ported
- AMP MASS 500 10D2 V.2 0.46 ft³ sealed · 0.81 ft³ ported
- Helix IQ W10-DVC2 (2x2 Ohm) 0.53 ft³ sealed · 0.88 ft³ ported
- Dayton Audio SS10-22 0.53 ft³ sealed · 0.85 ft³ ported
FAQ
What box does the Fi Audio X10 S2 need?
Recommended net volume: 0.42 ft³ sealed, 0.78 ft³ ported tuned to 43 Hz — for one sub in a sedan at 400 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the Fi Audio X10 S2 Thiele/Small specs?
Fs 36.4 Hz, Qts 0.41, Vas 0.78 ft³, Xmax 0.71″, Sd 48.1 in².
What is the Fi Audio X10 S2 mounting depth?
Mounting depth is 5 3/4″, cutout diameter 9 1/4″. The inside depth of the box must exceed the mounting depth by at least 1″.
How much power does the Fi Audio X10 S2 handle and how do I wire it?
RMS power rating: 400 W. Wiring for several subs and amp power — in the wiring calculator.
Is the Fi Audio X10 S2 better sealed or ported?
EBP 83: both work — sealed 0.42 ft³ is tighter and smaller, ported 0.78 ft³ tuned to 43 Hz is deeper and louder.
What port does the Fi Audio X10 S2 need?
For the 0.78 ft³ ported box tuned to 43 Hz: 2 round ports Ø2 1/2″, 16 11/16″ long, area 10 in²; or a round port Ø3 9/16″, ≈ 15 15/16″ long. Port air speed at 400 W: 105 ft/s.
What box do two Fi Audio X10 S2 subs need?
Two subs need twice the volume: 0.85 ft³ sealed, or 1.55 ft³ ported at the same 43 Hz tuning with twice the port area. One shared chamber or one per sub — whatever fits your vehicle.