SPL Dynamics V-300S4

12″ subwoofer · 4 Ω · 350 W RMS

30 HzFs, resonance

0.47Qts

2.52 ft³Vas

0.39″Xmax

350 WRMS

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, 350 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

1.31 ft³ (37 L)

Net volume

Bass character (Qtc)	Tight and punchy · 0.80
Fc	51 Hz
F3 (−3 dB, no cabin gain)	49 Hz
Example box (outside)	13 3/4″ × 13 3/4″ × 17 3/8″

Open sealed box in designer

Ported

deeper, louder

2.01 ft³ (57 L)

Net volume

Tuning (Fb)	33 Hz
Port	slot 1 9/16 × 14 5/16″, 23 5/8″ long
Port velocity at 350 W	54 ft/s
F3 (−3 dB, no cabin gain)	33 Hz
Example box (outside)	31 1/2″ × 15 3/4″ × 11 5/8″

Open ported box in designer

Deeper: 3.07 ft³ (87 L) tuned to 31 Hz, 31 1/2″ × 15 3/4″ × 15 5/8″ 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	350 W
Fs	30 Hz
Qts	0.47
Qes	0.528
Qms	3.94
Vas	2.52 ft³

Re	3.2 Ω
Sd	79.3 in²
Xmax	0.39″
Vd	31.2 in³ calc.
Mms	146 g calc.
BL	12.9 T·m calc.
EBP	57 — sealed or ported calc.
Sensitivity, 1 W / 1 m	87.6 dB calc.

Mounting dimensions

Cutout diameter	10 3/4″
Mounting depth	6″
Overall diameter	12 11/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 79.3 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/20120610175159/http://www.spldynamics.fi:80/products/subwoof

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-12S4 12″ · 4 Ω

Similar 12″ subwoofers from other brands

Close in Fs, Qts and Vas — a box of similar volume will suit them.

Polk Audio db1240DVC 1.24 ft³ sealed · 1.91 ft³ ported
Polk Audio db1240 1.09 ft³ sealed · 2.01 ft³ ported
Polk Audio DXi124 SVC 1.09 ft³ sealed · 2.01 ft³ ported
Black Hydra Gamma-12 1.31 ft³ sealed · 1.87 ft³ ported
Alpine SWA-12S4 (Atom) 1.48 ft³ sealed · 1.91 ft³ ported
Polk Audio DXi1240DVC 1.62 ft³ sealed · 2.15 ft³ ported

FAQ

What box does the SPL Dynamics V-300S4 need?

Recommended net volume: 1.31 ft³ sealed, 2.01 ft³ ported tuned to 33 Hz — for one sub in a sedan at 350 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-300S4 Thiele/Small specs?

Fs 30 Hz, Qts 0.47, Vas 2.52 ft³, Xmax 0.39″, Sd 79.3 in².

What is the SPL Dynamics V-300S4 mounting depth?

Mounting depth is 6″, cutout diameter 10 3/4″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the SPL Dynamics V-300S4 handle and how do I wire it?

RMS power rating: 350 W. Wiring for several subs and amp power — in the wiring calculator.