Rockford Fosgate P1S4-12

12" · 4 Ω · 250 W · 85.1 dB · datasheet ↗

Thiele-Small parameters

Nominal size	12"
Impedance	4 Ω
Fs	25 Hz
Qts	0.55
Qes	0.656
Qms	3.4
Vas	88.3 L
Sd	548 cm²
Xmax	9 mm
Re	3.6 Ω
Bl	12.99 T·m
Mms	195.8 g
Pe	250 W
Sensitivity	85.1 dB

Alignment hint

EBP	38 · sealed
Sealed Vb (Qtc ≈ 0.71)	≈ 135.2 L

EBP < 50: favours a sealed (closed) alignment.

Rules of thumb from T/S parameters only. Verify against a real simulation before cutting wood.

Substitute candidates

Driver	Fs (Hz)	Qts	Vas (L)	Xmax (mm)	Sens (dB)	Fit	Notes	Compare
Rockford Fosgate P1S2-12	25 =	0.55 =	88.3 =	9 =	85.1 =	close	2 Ω vs 4 Ω: amp load changes	+
Dayton Audio RSS315HFA-8	25 =	0.526 -0.02	75 -13.3	9.9 +0.9	85.5 +0.4	close	8 Ω vs 4 Ω: amp load changes	+
Infinity REFERENCE 1200S	22.8 -2.2	0.54 -0.01	97.56 +9.26	7.6 -1.4	84.4 -0.7	close	Xmax 7.6 mm < 9 mm: lower excursion-limited SPL	+
Infinity REFERENCE 1240W	25.4 +0.4	0.47 -0.08	84.4 -3.9	11.5 +2.5	86.3 +1.2	close		+
Infinity REFERENCE 1250W	25.4 +0.4	0.47 -0.08	84.4 -3.9	11.5 +2.5	86.3 +1.2	close		+
JL Audio 12W1V3-4	26.21 +1.21	0.5 -0.05	76.63 -11.67	11 +2	86.1 +1	close		+
JL Audio 12W1V3-2	26.55 +1.55	0.52 -0.03	72 -16.3	11 +2	85.9 +0.8	close	2 Ω vs 4 Ω: amp load changes	+
Focal AUDITOR RSB-300	25 =	0.466 -0.08	93 +4.7	10.2 +1.2	87.4 +2.3	close	8 Ω vs 4 Ω: amp load changes	+
Dayton Audio RSS315HF-4	25 =	0.489 -0.06	85.1 -3.2	10.1 +1.1	89.4 +4.3	close		+
Focal 30A4	24.7 -0.3	0.671 +0.12	86.9 -1.4	8.5 -0.5	87.3 +2.2	close	8 Ω vs 4 Ω: amp load changes · Xmax 8.5 mm < 9 mm: lower excursion-limited SPL	+

Compare the closest 3 against the P1S4-12 →

Ranked on parameter similarity only (Qts, Fs, Vas, Xmax, sensitivity). Same nominal size required. A hint, not a simulation, model the swap before cutting or buying.

Used in enclosures (0)

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