Hertz Energy ES F25.5 (free-air/shallow, SVC 4 ohm)

10″ subwoofer · 4 Ω · 300 W RMS

Fs 39 HzQts 0.44Vas 1.42 ft³Xmax 0.24″

Recommended box

For a sedan, one sub, 300 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 volume0.64 ft³ (18 L)
Qtc0.80
Fc70 Hz
F3 (−3 dB, no cabin gain)67 Hz
Example box (outside)12 3/16″ × 12 3/16″ × 11 13/16″
Open sealed box in designer

Ported

Net volume2.08 ft³ (59 L)
Tuning (Fb)37 Hz
Portslot 1 9/16 × 14 5/16″, 17 1/4″ long
Port velocity at 300 W61 ft/s
F3 (−3 dB, no cabin gain)35 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 11 1/4″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs39 Hz
Qts0.44
Qes0.49
Qms4.71
Vas1.42 ft³
Re2.9 Ω
Sd57.9 in²
Xmax0.24″
Vd13.7 in³ calc.
Mms82 g calc.
BL10.9 T·m calc.
EBP80 — sealed or ported calc.
Sensitivity, 1 W / 1 m88.9 dB calc.

General

Size10″
Voice coils4 Ω
RMS power300 W

Mounting dimensions

Ø10 1/16″cutout Ø9 1/16″mounting depth 3 3/8″magnet Ø≈ 5 7/8″
Cutout diameter9 1/16″
Mounting depth3 3/8″
Overall diameter10 1/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 57.9 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

Other Hertz 10″ models