SPL Dynamics SPL-300D1A

12″ subwoofer · dual 1 Ω · 1,500 W RMS

35.1 HzFs, resonance

0.35Qts

0.65 ft³Vas

0.45″Xmax

1,500 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, 1,500 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

0.81 ft³ (23 L)

Net volume

Bass character (Qtc)	Dry and tight · 0.47
Fc	47 Hz
F3 (−3 dB, no cabin gain)	82 Hz
Example box (outside)	14 9/16″ × 14 9/16″ × 10 9/16″

Open sealed box in designer

Ported

deeper, louder

2.61 ft³ (74 L)

Net volume

Tuning (Fb)	34 Hz
Port	slot 4 1/8 × 14 5/16″, 46 1/16″ long
Port velocity at 1,500 W	63 ft/s
F3 (−3 dB, no cabin gain)	30 Hz
Example box (outside)	31 1/2″ × 15 3/4″ × 19 3/8″

Open ported box in designer

Deeper: 1.70 ft³ (48 L) tuned to 26 Hz, 18 3/4″ × 15 3/4″ × 20 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	dual 1 Ω
RMS power	1,500 W
Fs	35.1 Hz
Qts	0.35
Qes	0.382
Qms	3.82
Vas	0.65 ft³

Re (one coil)	0.9 Ω
Sd	87.7 in²
Xmax	0.45″
Vd	39.7 in³ calc.
Mms	510 g calc.
BL	16.3 T·m calc.
EBP	92 — sealed or ported calc.
Sensitivity, 1 W / 1 m	85.2 dB calc.

Mounting dimensions

Cutout diameter	11 5/16″
Mounting depth	8 1/8″
Overall diameter	12 13/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 87.7 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/20120426224343/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-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
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.

Fi Audio NEO 4.9 12 D1 0.94 ft³ sealed · 2.19 ft³ ported
Fi Audio NEO 4.9 12 D2 0.94 ft³ sealed · 2.19 ft³ ported
Fi Audio MT 12 D1 0.94 ft³ sealed · 2.19 ft³ ported
Fi Audio TEAM 12 D1 1.06 ft³ sealed · 2.19 ft³ ported
Fi Audio TEAM v2 12 D1 0.94 ft³ sealed · 2.19 ft³ ported
Fi Audio MT 12 D2 0.94 ft³ sealed · 2.19 ft³ ported

FAQ

What box does the SPL Dynamics SPL-300D1A need?

Recommended net volume: 0.81 ft³ sealed, 2.61 ft³ ported tuned to 34 Hz — for one sub in a sedan at 1,500 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the SPL Dynamics SPL-300D1A Thiele/Small specs?

Fs 35.1 Hz, Qts 0.35, Vas 0.65 ft³, Xmax 0.45″, Sd 87.7 in².

What is the SPL Dynamics SPL-300D1A mounting depth?

Mounting depth is 8 1/8″, cutout diameter 11 5/16″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the SPL Dynamics SPL-300D1A handle and how do I wire it?

RMS power rating: 1,500 W. Dual 1 Ω voice coils: series gives 2 Ω, parallel gives 0.5 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.