DD Audio 818f D1

18″ subwoofer · dual 1 Ω · 2,500 W RMS

Fs 27 HzQts 0.79Vas 5.48 ft³Xmax 1.22″

Recommended box

For a sedan, one sub, 2,500 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

Net volume4.13 ft³ (117 L)
Qtc1.21
Fc41 Hz
F3 (−3 dB, no cabin gain)32 Hz
Example box (outside)20 1/16″ × 20 1/16″ × 23 5/16″
Open sealed box in designer

Ported

Net volume6.99 ft³ (198 L)
Tuning (Fb)32 Hz
Portslot 4 3/4 × 19 7/16″, 26 3/8″ long
Port velocity at 2,500 W64 ft/s
F3 (−3 dB, no cabin gain)27 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 27 7/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs27 Hz
Qts0.79
Qes0.89
Qms7.05
Vas5.48 ft³
Re (one coil)≈ 0.85 Ω
Sd≈ 180.6 in²
Xmax1.22″
EBP30 — suits sealed calc.
Sensitivity, 1 W / 1 m87.4 dB calc.

General

Size18″
Voice coilsdual 1 Ω
RMS power2,500 W

Mounting dimensions

Ø18 1/4″cutout Ø16 3/4″mounting depth 12 1/2″magnet Ø≈ 10 7/8″
Cutout diameter16 3/4″
Mounting depth12 1/2″
Overall diameter18 1/4″

“≈” 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

Other DD Audio 18″ models