SPL Dynamics V-12S4

12″ subwoofer · 4 Ω · 300 W RMS

23 HzFs, resonance

0.31Qts

4.80 ft³Vas

0.28″Xmax

300 WRMS

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, 300 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

0.81 ft³ (23 L)

Net volume

Bass character (Qtc)	Tight and punchy · 0.80
Fc	60 Hz
F3 (−3 dB, no cabin gain)	58 Hz
Example box (outside)	14 3/16″ × 14 3/16″ × 11 3/16″

Open sealed box in designer

Ported

deeper, louder

2.44 ft³ (69 L)

Net volume

Tuning (Fb)	30 Hz
Port	slot 1 9/16 × 14 5/16″, 23 9/16″ long
Port velocity at 300 W	56 ft/s
F3 (−3 dB, no cabin gain)	31 Hz
Example box (outside)	31 1/2″ × 15 3/4″ × 13 5/16″

Open ported box in designer

Deeper: 2.40 ft³ (68 L) tuned to 31 Hz, 31 1/2″ × 15 3/4″ × 13 1/16″ outside — a bigger box with flatter deep bass. Open in the calculator

Where to buy Amazon

Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Size	12″
Voice coils	4 Ω
RMS power	300 W
Fs	23 Hz
Qts	0.31
Qes	0.32
Qms	6.55
Vas	4.80 ft³

Re	3.6 Ω
Sd	82.1 in²
Xmax	0.28″
Vd	22.6 in³ calc.
Mms	140 g calc.
BL	15.1 T·m calc.
EBP	72 — sealed or ported calc.
Sensitivity, 1 W / 1 m	89.1 dB calc.

Mounting dimensions

Cutout diameter	10 7/8″
Mounting depth	5 5/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 82.1 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

web.archive.org/web/20060718183306/http://www.spldynamics.fi:80/v-sub/v-12s4-e.h

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 SW-300D4 12″ · dual 4 Ω
SPL Dynamics V-12S 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.

Orion XtrPro 12D (2000) 0.88 ft³ sealed · 2.40 ft³ ported
Polk Audio EX12 (EX Series II) 0.74 ft³ sealed · 2.26 ft³ ported
Orion 2NT 12 SVC 0.71 ft³ sealed · 2.30 ft³ ported
Helix W12 Competition (1x4 Ohm) 0.74 ft³ sealed · 2.37 ft³ ported
Dayton Audio SD315A-88 1.13 ft³ sealed · 2.40 ft³ ported
Ground Zero GZHW 12SPL-D2 FLAT (2x2 Ohm) 0.78 ft³ sealed · 2.51 ft³ ported

FAQ

What box does the SPL Dynamics V-12S4 need?

Recommended net volume: 0.81 ft³ sealed, 2.44 ft³ ported tuned to 30 Hz — for one sub in a sedan at 300 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the SPL Dynamics V-12S4 Thiele/Small specs?

Fs 23 Hz, Qts 0.31, Vas 4.80 ft³, Xmax 0.28″, Sd 82.1 in².

What is the SPL Dynamics V-12S4 mounting depth?

Mounting depth is 5 5/16″, cutout diameter 10 7/8″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the SPL Dynamics V-12S4 handle and how do I wire it?

RMS power rating: 300 W. Wiring for several subs and amp power — in the wiring calculator.