American Bass HD-844

8″ subwoofer · dual 4 Ω · 400 W RMS

Fs 51.5 HzQts 0.47Vas 0.12 ft³Xmax 0.55″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 400 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 volume0.32 ft³ (9 L)
Qtc0.55
Fc60 Hz
F3 (−3 dB, no cabin gain)83 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 9 1/4″
Open sealed box in designer

Ported

Net volume0.64 ft³ (18 L)
Tuning (Fb)31 Hz
Portslot 1 15/16 × 14 5/16″, 119 1/16″ long
Port velocity at 400 W32 ft/s
F3 (−3 dB, no cabin gain)29 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 12 7/8″

The volume and tuning are the recommendation, but the port doesn’t fit this example box. Size the box and port in the designer.

Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs51.5 Hz
Qts0.47
Qes0.532
Qms4.2
Vas0.12 ft³
Re (one coil)≈ 3.4 Ω
Sd≈ 33.3 in²
Xmax0.55″
EBP97 — sealed or ported calc.
Sensitivity, 1 W / 1 m81.4 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power400 W

Mounting dimensions

Ø8 9/16″cutout Ø7 3/16″mounting depth 6 5/16″magnet Ø≈ 4 11/16″
Cutout diameter7 3/16″
Mounting depth6 5/16″
Overall diameter8 9/16″

“≈” 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

Other American Bass 8″ models