Ascendant Audio SMD Signature 15 D2

15″ subwoofer · dual 2 Ω · 3,500 W RMS

30.1 HzFs, resonance

0.27Qts

1.95 ft³Vas

1.26″Xmax

3,500 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, 3,500 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

2.07 ft³ (58.5 L)

Net volume

Bass character (Qtc)	Dry and tight · 0.38
Fc	42 Hz
F3 (−3 dB, no cabin gain)	96 Hz
Example box (outside)	17 5/16″ × 17 5/16″ × 16 3/4″

Open sealed box in designer

Ported

deeper, louder

3.71 ft³ (105 L)

Net volume

Tuning (Fb)	33 Hz
Port	slot 5 7/8 × 16 11/16″, 57 1/16″ long
Port velocity at 3,500 W	70 ft/s
F3 (−3 dB, no cabin gain)	30 Hz
Example box (outside)	31 1/2″ × 18 1/8″ × 26 7/8″

Open ported box in designer

Deeper: 2.40 ft³ (68 L) tuned to 28 Hz, 31 1/2″ × 18 1/8″ × 15 1/4″ 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 2 Ω
RMS power	3,500 W
Fs	30.1 Hz
Qts	0.27
Qes	0.29
Qms	4.99
Vas	1.95 ft³

Re (one coil)	1.35 Ω
Sd	125.6 in²
Xmax	1.26″
Vd	158.2 in³ calc.
Mms	472 g calc.
BL	20.4 T·m calc.
EBP	104 — suits ported calc.
Sensitivity, 1 W / 1 m	89.1 dB calc.

Mounting dimensions

Cutout diameter	14 1/8″
Mounting depth	14 1/4″
Overall diameter	15 5/8″

“≈” 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/20100417121144/http://www.ascendantaudio.com:80/smd.php

Other Ascendant Audio 15″ models

Ascendant Audio Chaos 15 D1 15″ · dual 1 Ω
Ascendant Audio Chaos 15 D2 15″ · dual 2 Ω
Ascendant Audio Havoc 15 D1 15″ · dual 1 Ω
Ascendant Audio Havoc 15 D2 15″ · dual 2 Ω
Ascendant Audio Mayhem 15 D1 15″ · dual 1 Ω
Ascendant Audio Mayhem 15 D2 15″ · dual 2 Ω
Ascendant Audio SMD Signature 15 D1 15″ · dual 1 Ω
Ascendant Audio SMD V2 15 D1 15″ · dual 1 Ω
Ascendant Audio SMD V2 15 D2 15″ · dual 2 Ω
Ascendant Audio TEAM 15 D1 15″ · dual 1 Ω
Ascendant Audio TEAM 15 D2 15″ · dual 2 Ω

Similar 15″ subwoofers from other brands

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

American Bass VELOCITY-1511 1.32 ft³ sealed · 3.43 ft³ ported
SoundQubed HDX415 D1 1.27 ft³ sealed · 3.78 ft³ ported
DC Audio Level 5 M5 15 D0.7 1.70 ft³ sealed · 3.64 ft³ ported
DC Audio Level 5 M5 15 D1 1.70 ft³ sealed · 3.64 ft³ ported
DC Audio Level 5 M5 15 D2 1.70 ft³ sealed · 3.64 ft³ ported
Edge EDS15D1-E7 1.06 ft³ sealed · 3.46 ft³ ported

FAQ

What box does the Ascendant Audio SMD Signature 15 D2 need?

Recommended net volume: 2.07 ft³ sealed, 3.71 ft³ ported tuned to 33 Hz — for one sub in a sedan at 3,500 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the Ascendant Audio SMD Signature 15 D2 Thiele/Small specs?

Fs 30.1 Hz, Qts 0.27, Vas 1.95 ft³, Xmax 1.26″, Sd 125.6 in².

What is the Ascendant Audio SMD Signature 15 D2 mounting depth?

Mounting depth is 14 1/4″, cutout diameter 14 1/8″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the Ascendant Audio SMD Signature 15 D2 handle and how do I wire it?

RMS power rating: 3,500 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.