Soundstream EXACT 8

8″ subwoofer · 4 Ω · 200 W RMS

34 HzFs, resonance

0.42Qts

0.59 ft³Vas

0.41″Xmax

200 WRMS

Source	web.archive.org · manufacturer data
Checked against source	October 2026
Thiele/Small parameters	complete
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, 200 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

0.28 ft³ (8 L)

Net volume

Bass character (Qtc)	Flat and accurate · 0.74
Fc	60 Hz
F3 (−3 dB, no cabin gain)	60 Hz
Example box (outside)	10 5/8″ × 10 5/8″ × 7 7/8″

Open sealed box in designer

Ported

deeper, louder

0.53 ft³ (15 L)

Net volume

Tuning (Fb)	45 Hz
Port	round port Ø2 1/2″, 10 9/16″ long
Port velocity at 200 W	126 ft/s
F3 (−3 dB, no cabin gain)	40 Hz
Example box (outside)	15 5/8″ × 15 3/4″ × 6 1/2″

At 200 W this example’s port will be noisy: air speed 126 ft/s, while the limit is 82 ft/s. It stays quiet up to about 85 W. Full power needs a port of at least 7.6 in², which means a bigger box than this example — size it in the designer.

Open ported box in designer

Deeper: 0.74 ft³ (21 L) tuned to 42 Hz, 23 5/16″ × 15 3/4″ × 6 1/2″ 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	8″
Voice coils	4 Ω
RMS power	200 W
Fs	34 Hz
Qts	0.42
Qes	0.45
Qms	7.28
Vas	0.59 ft³

Re	2.91 Ω
Sd	32.6 in²
Xmax	0.41″
Vd	13.3 in³ calc.
Mms	82 g calc.
BL	10.6 T·m calc.
EBP	76 — sealed or ported calc.
Sensitivity, 1 W / 1 m	83.6 dB calc.

Mounting dimensions

Cutout diameter	≈ 7 5/16″
Mounting depth	≈ 3 15/16″

“≈” 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/20060311051407/http://www.soundstream.com/manuals/EXACT%20SU

Other Soundstream 8″ models

Soundstream R3.8 8″ · dual 2 Ω
Soundstream USA8 8″ · dual 4 Ω

Similar 8″ subwoofers from other brands

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

Helix IK W8-DVC2 (2x2 Ohm) 0.32 ft³ sealed · 0.53 ft³ ported
JL Audio 8W1v3-4 0.28 ft³ sealed · 0.49 ft³ ported
Morel Ultimo 802 (SVC 2 ohm) 0.35 ft³ sealed · 0.60 ft³ ported
Audiobahn AW831X 0.32 ft³ sealed · 0.53 ft³ ported
Audio System HX 08 SQ 0.32 ft³ sealed · 0.53 ft³ ported
JBL GTO804 0.32 ft³ sealed · 0.53 ft³ ported

FAQ

What box does the Soundstream EXACT 8 need?

Recommended net volume: 0.28 ft³ sealed, 0.53 ft³ ported tuned to 45 Hz — for one sub in a sedan at 200 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the Soundstream EXACT 8 Thiele/Small specs?

Fs 34 Hz, Qts 0.42, Vas 0.59 ft³, Xmax 0.41″, Sd 32.6 in².

How much power does the Soundstream EXACT 8 handle and how do I wire it?

RMS power rating: 200 W. Wiring for several subs and amp power — in the wiring calculator.