Soundstream T4-15

15″ subwoofer · dual 1 Ω · 1,000 W RMS

34 HzFs, resonance

0.40Qts

2.08 ft³Vas

0.55″Xmax

1,000 WRMS

Source	web.archive.org · manufacturer data
Checked against source	October 2026
Thiele/Small parameters	not in the spec sheet: Re, Sd — typical value for the size used
Mounting dimensions	0 of 4 — missing: cutout, mounting depth, frame outer diameter, magnet diameter; the designer will use an estimate

Recommended box

For a sedan, one sub, 1,000 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

1.13 ft³ (32 L)

Net volume

Bass character (Qtc)	Flat and accurate · 0.67
Fc	57 Hz
F3 (−3 dB, no cabin gain)	63 Hz
Example box (outside)	17 5/16″ × 17 5/16″ × 10 5/16″

Open sealed box in designer

Ported

deeper, louder

1.98 ft³ (56 L)

Net volume

Tuning (Fb)	34 Hz
Port	slot 2 3/16 × 16 11/16″, 37 5/16″ long
Port velocity at 1,000 W	61 ft/s
F3 (−3 dB, no cabin gain)	34 Hz
Example box (outside)	31 1/2″ × 18 1/8″ × 12 1/4″

Open ported box in designer

Deeper: 2.37 ft³ (67 L) tuned to 35 Hz, 31 1/2″ × 18 1/8″ × 13 3/16″ 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	15″
Voice coils	dual 1 Ω
RMS power	1,000 W
Fs	34 Hz
Qts	0.40
Qes	0.449
Qms	3.72

Vas	2.08 ft³
Re (one coil)	≈ 0.85 Ω
Sd	≈ 124 in²
Xmax	0.55″
EBP	76 — sealed or ported calc.
Sensitivity, 1 W / 1 m	89.1 dB calc.

Mounting dimensions

Cutout diameter	≈ 14″
Mounting depth	≈ 7 1/16″

“≈” 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/20060911083056/http://www.soundstream.com:80/manuals/2006/sb

Other Soundstream 15″ models

Soundstream PCW-15 15″ · dual 4 Ω
Soundstream PWS-15 15″ · dual 4 Ω
Soundstream PXW-15 15″ · dual 4 Ω
Soundstream PXW-15/2 15″ · dual 2 Ω
Soundstream R1-15 15″ · dual 4 Ω
Soundstream R1-15L 15″ · dual 4 Ω
Soundstream R3.15 15″ · dual 2 Ω
Soundstream RBW-15 15″ · dual 4 Ω
Soundstream SPLX-152 ('07-'08) 15″ · dual 2 Ω
Soundstream SPLX-152 (2006) 15″ · dual 2 Ω
Soundstream SPLX-152HX 15″ · dual 2 Ω
Soundstream SPLX-154 ('07-'08) 15″ · 4 Ω

Similar 15″ subwoofers from other brands

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

Hifonics CX15D2 1.48 ft³ sealed · 3.88 ft³ ported
DD Audio 9915b ESP D2 1.75 ft³ sealed · 3.67 ft³ ported
DD Audio 9915c D1 1.75 ft³ sealed · 3.67 ft³ ported
DD Audio 9915c D2 1.75 ft³ sealed · 3.67 ft³ ported
Fi Audio NEO 3.7 15 D2 1.59 ft³ sealed · 3.71 ft³ ported
ESX VE1522 (2x2 Ohm) 1.48 ft³ sealed · 3.88 ft³ ported

FAQ

What box does the Soundstream T4-15 need?

Recommended net volume: 1.13 ft³ sealed, 1.98 ft³ ported tuned to 34 Hz — for one sub in a sedan at 1,000 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the Soundstream T4-15 Thiele/Small specs?

Fs 34 Hz, Qts 0.40, Vas 2.08 ft³, Xmax 0.55″.

How much power does the Soundstream T4-15 handle and how do I wire it?

RMS power rating: 1,000 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.