Compare subwoofer configurations by total cone area. Answer the classic"6 12s vs 3 18s" debate!
3× 18" has 11.1% more cone area than 6× 12". More cone area generally means more air movement potential, but other factors like power handling, enclosure design, and driver quality also matter significantly.
| Size | Area (1×) | Area (2×) | Area (4×) | Area (6×) |
|---|---|---|---|---|
| 7" | 33.2 in² | 66.4 in² | 132.7 in² | 199.1 in² |
| 8" | 50.3 in² | 100.5 in² | 201.1 in² | 301.6 in² |
| 10" | 78.5 in² | 157.1 in² | 314.2 in² | 471.2 in² |
| 12" | 113.1 in² | 226.2 in² | 452.4 in² | 678.6 in² |
| 15" | 176.7 in² | 353.4 in² | 706.9 in² | 1060.3 in² |
| 18" | 254.5 in² | 508.9 in² | 1017.9 in² | 1526.8 in² |
| 21" | 346.4 in² | 692.7 in² | 1385.4 in² | 2078.2 in² |
| 24" | 452.4 in² | 904.8 in² | 1809.6 in² | 2714.3 in² |
Sd (cone area) measures the radiating surface of a driver—the part that actually pushes air. Basic circle math: A = π × r²
Larger surface area can move more air per stroke. That air displacement creates the pressure waves you feel. But area alone doesn't tell the whole story—motor strength, enclosure tuning, and excursion capability all factor into real-world output.
Six 12s versus three 18s—every audio forum has this thread. The numbers: 6× 12" = 678.6 in², 3× 18" = 763.4 in². Real-world factors like trunk space, enclosure volume, and budget usually settle the debate.
Total air displacement combines area with throw: Vd = Sd × Xmax. A compact driver with serious excursion can match a bigger cone with shorter travel.
Nominal vs. effective Sd: Manufacturer Sd specs use the effective piston area, which is smaller than what the nominal diameter suggests. A "12-inch" driver typically has Sd closer to a 10.5-11" circle due to the surround. For precise Vd calculations, use the Sd from your driver's datasheet rather than nominal size.