What do these Specs mean?

[Sythlord79 10+ year member]

Im a noob and trying to compare Subwoofers. I was wondering what each of these specs mean. Does it tell me accuracy? how much air pressure I'd feel? what do these numbers mean exactly? I was hoping to have a better sense of what the differences between subs when comparing. I just randomly picked this sub's specs as an example. Thanks!

Nominal Impedance (Znom): 4 ohm

Thermal Power Handling (Pt): 400W

Driver Displacement: 0.096 cu. ft. / 2.72 liters

Free Air Resonance (Fs): 23.66 Hz

Electrical “Q” (Qes): 0.465

Mechanical “Q” (Qms): 6.774

Total Speaker “Q” (Qts): 0.435

Equivalent Compliance (Vas): 4.793 cu. ft. / 135.74 liters

One-Way, Linear Excursion (Xmax)*: 0.610 in. / 15.5 mm

Reference Efficiency (no): 0.371%

Efficiency (1W/1m)**: 87.90 dB SPL

Effective Piston Area (Sd): 103.850 sq. in. / 0.0670 sq. m.

DC Resistance (Re): 3.569 ohm

Net Weight: 17.75 lbs. / 8.05 kg

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[n2audio 5,000+ posts]

subs are strange animals.

You can put "X" sub, driven by "X" amp in "X" enclosure, and it may sound fantastic.

Same sub, same amp, "Y" enclosure - not good at all.

Same sub, same amp, back to "X" enclosure, different car and notice a significant loss in SPL.

However - by looking at those specs, I see a relatively low power sub with a lot of x-max, and a low resonant frequency.

I'm no sub expert by any means, but it seems that sub should get low, and play fairly loud w/o a great deal of power.

Seems like a winner, but specs and theories only tell half the story.