SPL Dynamics SW-300D4
12″ subwoofer · dual 4 Ω · 450 W RMS
| Source | web.archive.org · manufacturer data |
|---|---|
| Checked against source | October 2026 |
| Thiele/Small parameters | complete |
| Mounting dimensions | 2 of 4 — missing: frame outer diameter, magnet diameter; the designer will use an estimate |
Recommended box
For a sedan, one sub, 450 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 | 44 Hz |
| F3 (−3 dB, no cabin gain) | 41 Hz |
| Example box (outside) | 14 3/16″ × 14 3/16″ × 20 15/16″ |
Ported
deeper, louder| Tuning (Fb) | 34 Hz |
|---|---|
| Port | slot 1 9/16 × 14 5/16″, 38 5/16″ long |
| Port velocity at 450 W | 50 ft/s |
| F3 (−3 dB, no cabin gain) | 31 Hz |
| Example box (outside) | 20″ × 15 3/4″ × 14 9/16″ |
Deeper: 3.00 ft³ (85 L) tuned to 28 Hz, 31 1/2″ × 15 3/4″ × 16 11/16″ 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 | 12″ |
|---|---|
| Voice coils | dual 4 Ω |
| RMS power | 450 W |
| Fs | 35 Hz |
| Qts | 0.64 |
| Qes | 0.7 |
| Qms | 7.3 |
| Vas | 0.97 ft³ |
| Re (one coil) | 3.6 Ω |
|---|---|
| Sd | 77.9 in² |
| Xmax | 0.51″ |
| Vd | 39.9 in³ calc. |
| Mms | 268 g calc. |
| BL | 17.4 T·m calc. |
| EBP | 50 — sealed or ported calc. |
| Sensitivity, 1 W / 1 m | 84.3 dB calc. |
Mounting dimensions
| Cutout diameter | 11 1/8″ |
|---|---|
| Mounting depth | 7 5/16″ |
Cone area (Sd) calculated from Fs, Vas and Mms: 77.9 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
Other SPL Dynamics 12″ models
- SPL Dynamics PRO-12D2 MK3 12″ · dual 2 Ω
- SPL Dynamics PRO-12D2 MK4 12″ · dual 2 Ω
- SPL Dynamics PRO-12D4 MK3 12″ · dual 4 Ω
- SPL Dynamics PRO-12D4 MK4 12″ · dual 4 Ω
- SPL Dynamics PRO-300D2 12″ · dual 2 Ω
- SPL Dynamics PRO-300D4 12″ · dual 4 Ω
- SPL Dynamics SPL-300D1A 12″ · dual 1 Ω
- SPL Dynamics SPL-300D2 12″ · dual 2 Ω
- SPL Dynamics SW-300D2 12″ · dual 2 Ω
- SPL Dynamics V-12S 12″ · 4 Ω
- SPL Dynamics V-12S4 12″ · 4 Ω
- SPL Dynamics V-300D2 12″ · dual 2 Ω
Similar 12″ subwoofers from other brands
Close in Fs, Qts and Vas — a box of similar volume will suit them.
- Hertz SPL Show SS 12 D2 (DVC 2+2 ohm) 1.48 ft³ sealed · 1.94 ft³ ported
- DD Audio 512e D2 1.73 ft³ sealed · 2.26 ft³ ported
- DD Audio 512e D4 1.73 ft³ sealed · 2.26 ft³ ported
- Diamond CM312D2 1.73 ft³ sealed · 1.20 ft³ ported
- JL Audio 12TW1-2 1.09 ft³ sealed · 1.13 ft³ ported
- Kicker CompQ 12" 4-Ohm DVC (51CWQ124) 1.24 ft³ sealed · 2.51 ft³ ported
FAQ
What box does the SPL Dynamics SW-300D4 need?
Recommended net volume: 1.73 ft³ sealed, 1.24 ft³ ported tuned to 34 Hz — for one sub in a sedan at 450 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.
What are the SPL Dynamics SW-300D4 Thiele/Small specs?
Fs 35 Hz, Qts 0.64, Vas 0.97 ft³, Xmax 0.51″, Sd 77.9 in².
What is the SPL Dynamics SW-300D4 mounting depth?
Mounting depth is 7 5/16″, 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 SPL Dynamics SW-300D4 handle and how do I wire it?
RMS power rating: 450 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.