Fostex L 869

31.5" · 8 Ω · 150 W · 99.3 dB · datasheet ↗

Thiele-Small parameters

Nominal size	31.5"
Impedance	8 Ω
Fs	15 Hz
Qts	0.454
Qes	0.49
Qms	6.1
Vas	6700 L
Sd	4000 cm²
Xmax	4 mm
Re	6.8 Ω
Bl	22.2 T·m
Mms	376.9 g
Pe	150 W
Sensitivity	99.3 dB

Alignment hint

EBP	31 · sealed
Sealed Vb (Qtc ≈ 0.71)	≈ 4699.1 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
Electro-Voice 30W vp	16 +1	0.269 -0.18	5947.2 -752.8	3.8 -0.2	104.1 +4.8	usable	60 W vs 150 W: lower power handling · Xmax 3.8 mm < 4 mm: lower excursion-limited SPL	+
Audio Dynamique 75IC	15.2 +0.2	0.277 -0.18	4023.2 -2676.8	9 +5	100.1 +0.8	risky		+
Clarion SRW800	17 +2	0.401 -0.05	2840.2 -3859.8	13.8 +9.8	100.4 +1.1	risky	4 Ω vs 8 Ω: amp load changes	+
Fostex FW 800 N	18 +3	0.698 +0.24	3201.1 -3498.9	4.6 +0.6	96.6 -2.7	risky		+
Fluxmag 2950-Hifi	24.4 +9.4	0.589 +0.13	1313 -5387	5.5 +1.5	98.2 -1.1	risky		+
Fluxmag 2950-Sono	27.8 +12.8	0.761 +0.31	869 -5831	5.5 +1.5	96.9 -2.4	risky		+
Powersoft 30''-4MM M-FORCE 01 REVERSED	32 +17	0.207 -0.25	170 -6530	4.6 +0.6	111.1 +11.8	risky	0.5 Ω vs 8 Ω: amp load changes	+
Powersoft 30''-4MM M-FORCE 01 SHORT	32 +17	0.207 -0.25	170 -6530	4.6 +0.6	111.1 +11.8	risky	0.5 Ω vs 8 Ω: amp load changes	+
Powersoft 30''-4MM M-FORCE 01 STRAIGHT	32 +17	0.207 -0.25	170 -6530	4.6 +0.6	111.1 +11.8	risky	0.5 Ω vs 8 Ω: amp load changes	+
Powersoft 30''-3MM M-FORCE 01 STRAIGHT	30 +15	0.167 -0.29	230 -6470	4.8 +0.8	112.5 +13.2	risky	0.5 Ω vs 8 Ω: amp load changes	+

Compare the closest 3 against the L 869 →

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.