PSI Platform 3 18 D2

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

Fs 27.5 HzQts 0.30Vas 8.16 ft³Xmax 1.18″

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 volume1.89 ft³ (53.5 L)
Qtc0.69
Fc63 Hz
F3 (−3 dB, no cabin gain)69 Hz
Example box (outside)20 1/16″ × 20 1/16″ × 12 3/16″
Open sealed box in designer

Ported

Net volume3.88 ft³ (110 L)
Tuning (Fb)37 Hz
Portslot 3 15/16 × 19 7/16″, 31 1/4″ long
Port velocity at 2,500 W65 ft/s
F3 (−3 dB, no cabin gain)39 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 18 5/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs27.5 Hz
Qts0.30
Qes0.32
Qms5.01
Vas8.16 ft³
Re (one coil)1.95 Ω
Sd190.7 in²
Xmax1.18″
Vd225.2 in³ calc.
Mms311 g calc.
BL18.1 T·m calc.
EBP86 — sealed or ported calc.
Sensitivity, 1 W / 1 m93.8 dB calc.

General

Size18″
Voice coilsdual 2 Ω
RMS power2,500 W

Mounting dimensions

Ø18 1/2″cutout Ø16 3/4″mounting depth 9 3/4″magnet Ø≈ 10 7/8″
Cutout diameter16 3/4″
Mounting depth9 3/4″
Overall diameter18 1/2″

Judging by its value, the published Re is for both coils in series — converted to per coil.

“≈” 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 PSI 18″ models