Sundown Audio NSv2-18 D2

18″ subwoofer · dual 2 Ω · 2,000 W RMS

32.8 HzFs, resonance

0.49Qts

3.28 ft³Vas

2,000 WRMS

Source	web.archive.org · manufacturer data
Checked against source	October 2026
Thiele/Small parameters	not in the spec sheet: Xmax — typical value for the size used
Mounting dimensions	3 of 4 — missing: magnet diameter; the designer will use an estimate

Recommended box

For a sedan, one sub, 2,000 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

2.19 ft³ (62 L)

Net volume

Bass character (Qtc)	Flat and accurate · 0.78
Fc	52 Hz
F3 (−3 dB, no cabin gain)	50 Hz
Example box (outside)	20 1/16″ × 20 1/16″ × 13 11/16″

Open sealed box in designer

Ported

deeper, louder

2.90 ft³ (82 L)

Net volume

Tuning (Fb)	34 Hz
Port	2 round ports Ø3″, 9 1/16″ long
Port velocity at 2,000 W	261 ft/s
F3 (−3 dB, no cabin gain)	34 Hz
Example box (outside)	25 1/16″ × 20 7/8″ × 13 3/4″

At 2,000 W this example’s port will be noisy: air speed 261 ft/s, while the limit is 82 ft/s. It stays quiet up to about 190 W. Full power needs a port of at least 44.7 in², which means a bigger box than this example — size it in the designer.

Open ported box in designer

Deeper: 6.39 ft³ (181 L) tuned to 29 Hz, 31 1/2″ × 20 7/8″ × 27 11/16″ 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	18″
Voice coils	dual 2 Ω
RMS power	2,000 W
Fs	32.8 Hz
Qts	0.49
Qes	0.51
Qms	13.69
Vas	3.28 ft³

Re (one coil)	2.09 Ω
Sd	181.6 in²
Xmax	≈ 0.39″
Mms	494 g calc.
BL	20.4 T·m calc.
EBP	64 — sealed or ported calc.
Sensitivity, 1 W / 1 m	90.1 dB calc.

Mounting dimensions

Cutout diameter	16 3/4″
Mounting depth	11 1/4″
Overall diameter	18 3/8″

Cone area (Sd) calculated from Fs, Vas and Mms: 181.6 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/20181224185508/http://www.sundownaudio.com/index.php/product

Other Sundown Audio 18″ models

Sundown Audio Inhuman-18 D1 18″ · dual 1 Ω
Sundown Audio M18 D1 18″ · dual 1 Ω
Sundown Audio M18 D2 18″ · dual 2 Ω
Sundown Audio NSv1-18 D1 18″ · dual 1 Ω
Sundown Audio NSv4-18 D1 18″ · dual 1 Ω
Sundown Audio NSv4-18 D2 18″ · dual 2 Ω
Sundown Audio NSv5-18 D1 18″ · dual 1 Ω
Sundown Audio NSv5-18 D2 18″ · dual 2 Ω
Sundown Audio NSv6-18 D1 18″ · dual 1 Ω
Sundown Audio NSv6-18 D2 18″ · dual 2 Ω
Sundown Audio SAv2-18 D2 18″ · dual 2 Ω
Sundown Audio SAv2-18 D4 18″ · dual 4 Ω

Similar 18″ subwoofers from other brands

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

American Bass VFLCOMP-1822 2.12 ft³ sealed · 2.75 ft³ ported
Fi Audio MT 18 D2 2.38 ft³ sealed · 3.00 ft³ ported
Fi Audio TEAM 18 D2 2.30 ft³ sealed · 3.00 ft³ ported
Fi Audio TEAM v2 18 D2 2.38 ft³ sealed · 3.00 ft³ ported
American Bass GF-1811 2.40 ft³ sealed · 2.83 ft³ ported
Fi Audio SSDv4 18 D1 2.30 ft³ sealed · 3.00 ft³ ported

FAQ

What box does the Sundown Audio NSv2-18 D2 need?

Recommended net volume: 2.19 ft³ sealed, 2.90 ft³ ported tuned to 34 Hz — for one sub in a sedan at 2,000 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the Sundown Audio NSv2-18 D2 Thiele/Small specs?

Fs 32.8 Hz, Qts 0.49, Vas 3.28 ft³, Sd 181.6 in².

What is the Sundown Audio NSv2-18 D2 mounting depth?

Mounting depth is 11 1/4″, cutout diameter 16 3/4″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the Sundown Audio NSv2-18 D2 handle and how do I wire it?

RMS power rating: 2,000 W. Dual 2 Ω voice coils: series gives 4 Ω, parallel gives 1 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.