Rockford Fosgate P115S4

15" · 4 Ω · 200 W · 87.3 dB · datasheet ↗

Thiele-Small parameters

Nominal size	15"
Impedance	4 Ω
Fs	24 Hz
Qts	0.62
Qes	0.67
Qms	7.5
Vas	172 L
Sd	860 cm²
Xmax	8 mm
Re	3.7 Ω
Bl	14.8 T·m
Mms	261 g
Pe	200 W
Sensitivity	87.3 dB

Alignment hint

EBP	36 · sealed
Sealed Vb (Qtc ≈ 0.71)	≈ 571.9 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 P1S4-15	23 -1	0.55 -0.07	191.5 +19.5	9 +1	87.3 =	close		+
Rockford Fosgate P1S2-15	23 -1	0.55 -0.07	191.5 +19.5	9 +1	87.4 +0.1	close	2 Ω vs 4 Ω: amp load changes	+
Rockford Fosgate P3D4-15	22.4 -1.6	0.566 -0.05	155.8 -16.2	11 +3	87.3 =	close	8 Ω vs 4 Ω: amp load changes	+
Soundstream R1-15	23.7 -0.3	0.62 =	136.6 -35.4	17.2 +9.2	87.2 -0.1	close	8 Ω vs 4 Ω: amp load changes	+
Hertz Audio ES380.1	24.2 +0.2	0.52 -0.1	183 +11	9 +1	88.2 +0.9	close		+
Hertz Audio DS 38.3	23 -1	0.65 +0.03	244 +72	9 +1	87.9 +0.6	usable		+
Rockford Fosgate P2D4-15	20.9 -3.1	0.655 +0.04	219.6 +47.6	11.3 +3.3	87.3 =	usable	8 Ω vs 4 Ω: amp load changes	+
Oxygen AIR2 380	22.7 -1.3	0.543 -0.08	202.2 +30.2	11.5 +3.5	91.6 +4.3	usable		+
Powerbass M-1504	22 -2	0.442 -0.18	181.7 +9.7	11 +3	87.7 +0.4	usable		+
Dayton Audio IB385-8	21.5 -2.5	0.588 -0.03	248.9 +76.9	12.4 +4.4	89.8 +2.5	usable	8 Ω vs 4 Ω: amp load changes	+

Compare the closest 3 against the P115S4 →

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)

No enclosure in the catalog uses this driver yet.