Sundown Audio SDv3-12 D4
12″ subwoofer · dual 4 Ω · 500 W RMS
The Sundown Audio SDv3-12 D4 is a shallow 12″ sub (5″ mounting depth): it fits behind a truck seat or in a slim box. With Qts 0.49 and EBP 47 it suits a sealed box: tight bass in a small enclosure; a ported box would need a lot of volume.
| 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, 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 | 43 Hz |
| F3 (−3 dB, no cabin gain) | 40 Hz |
| Example box (outside) | 14 3/16″ × 14 3/16″ × 16 13/16″ |
Ported
deeper, louder| Tuning (Fb) | 30 Hz |
|---|---|
| Port | slot 1 9/16 × 14 5/16″, 34 1/16″ long |
| Port velocity at 500 W | 56 ft/s |
| F3 (−3 dB, no cabin gain) | 29 Hz |
| Example box (outside) | 31 1/2″ × 15 3/4″ × 11 3/8″ |
Deeper: 2.58 ft³ (73 L) tuned to 29 Hz, 31 1/2″ × 15 3/4″ × 14 3/4″ 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 | 12″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | 500 W |
| Fs | 26.2 Hz |
| Qts | 0.49 |
| Qes | 0.56 |
| Qms | 3.97 |
| Vas | 2.21 ft³ |
| Re (one coil) | 3.52 Ω |
|---|---|
| Sd | 66.8 in² |
| Xmax | 0.57″ |
| Vd | 38.1 in³ calc. |
| Mms | 155 g calc. |
| BL | 12.7 T·m calc. |
| EBP | 47 — suits sealed calc. |
| Sensitivity, 1 W / 1 m | 85 dB calc. |
Mounting dimensions
| Cutout diameter | 11 1/8″ |
|---|---|
| Mounting depth | 5″ |
| Overall diameter | 12 5/8″ |
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.
- Tacoma Access Cab — behind the front seats sealed 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
- 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 box
Cone area (Sd) calculated from Fs, Vas and Mms: 66.8 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
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 |
|---|---|---|---|---|---|---|
| Sundown Audio SDv3-12 D2 | dual 2 Ω | 1.91 Ω | 0.58 | 2.14 ft³ | 1.45 ft³ | 1.70 ft³ · 30 Hz |
| Sundown Audio SDv3-12 D4 | dual 4 Ω | 3.52 Ω | 0.56 | 2.21 ft³ | 1.34 ft³ | 1.77 ft³ · 30 Hz |
Other Sundown Audio 12″ models
- Sundown Audio Ev2-12 D2 12″ · dual 2 Ω
- Sundown Audio Ev2-12 D4 12″ · dual 4 Ω
- Sundown Audio Ev4-12 D2 12″ · dual 2 Ω
- Sundown Audio Ev4-12 D4 12″ · dual 4 Ω
- Sundown Audio HZ-12 D4 12″ · dual 4 Ω
- Sundown Audio HZS-12 D4 12″ · dual 4 Ω
- Sundown Audio LCSv1-12 D4 12″ · dual 4 Ω
- Sundown Audio LCSv2-12 D4 12″ · dual 4 Ω
- Sundown Audio M12 D1 12″ · dual 1 Ω
- Sundown Audio M12 D2 12″ · dual 2 Ω
- Sundown Audio NSv1-12 D2 12″ · dual 2 Ω
- Sundown Audio NSv2-12 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.
- Infinity Kappa 1200W (SSI 2 ohm) 1.41 ft³ sealed · 1.84 ft³ ported
- Rockford Fosgate Punch P3D2-12 1.24 ft³ sealed · 1.59 ft³ ported
- Soundstream RFW-12 1.17 ft³ sealed · 1.84 ft³ ported
- JL Audio 12W7AE-3 1.34 ft³ sealed · 1.77 ft³ ported
- Audiofrog GB12D4 1.38 ft³ sealed · 1.80 ft³ ported
- Kicx QS-300 (4+4) 1.34 ft³ sealed · 1.62 ft³ ported
FAQ
What box does the Sundown Audio SDv3-12 D4 need?
Recommended net volume: 1.34 ft³ sealed, 1.77 ft³ ported tuned to 30 Hz — for one sub in a sedan at 500 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the Sundown Audio SDv3-12 D4 Thiele/Small specs?
Fs 26.2 Hz, Qts 0.49, Vas 2.21 ft³, Xmax 0.57″, Sd 66.8 in².
What is the Sundown Audio SDv3-12 D4 mounting depth?
Mounting depth is 5″, 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 Sundown Audio SDv3-12 D4 handle and how do I wire it?
RMS power rating: 500 W. Dual 4 Ω voice coils: series gives 8 Ω, parallel gives 2 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.
Is the Sundown Audio SDv3-12 D4 better sealed or ported?
EBP 47: a sealed box (1.34 ft³) suits it best — tight bass in a compact enclosure. Ported is possible (1.77 ft³, tuned to 30 Hz) but larger.
What port does the Sundown Audio SDv3-12 D4 need?
For the 1.77 ft³ ported box tuned to 30 Hz: slot 1 9/16 × 14 5/16″, 34 1/16″ long, area 22.6 in²; or a round port Ø5 3/8″, ≈ 34 1/16″ long. Port air speed at 500 W: 56 ft/s.
What box do two Sundown Audio SDv3-12 D4 subs need?
Two subs need twice the volume: 2.68 ft³ sealed, or 3.53 ft³ ported at the same 30 Hz tuning with twice the port area. One shared chamber or one per sub — whatever fits your vehicle.