Fertin Acoustics B34D77

12" · 4 Ω · 200 W · 102 dB · datasheet ↗

Thiele-Small parameters

Nominal size	12"
Impedance	4 Ω
Fs	66.6 Hz
Qts	0.324
Qes	0.36
Qms	3.22
Vas	52.5 L
Sd	595 cm²
Xmax	2.5 mm
Re	3.45 Ω
Bl	14.7 T·m
Mms	54 g
Pe	200 W
Sensitivity	102 dB

Alignment hint

EBP	185 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 14 L

EBP > 100: favours a ported (bass-reflex) 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
Celestion TN1225	60.5 -6.1	0.33 +0.01	53.9 +1.4	2.5 =	99 -3	close	8 Ω vs 4 Ω: amp load changes	+
JBL G125-8	65 -1.6	0.32 =	70.8 +18.3	2.5 =	101.4 -0.6	close	8 Ω vs 4 Ω: amp load changes	+
JBL 2023H	67 +0.4	0.347 +0.02	48.8 -3.7	3.7 +1.2	99.8 -2.2	close	8 Ω vs 4 Ω: amp load changes	+
RCF L 12P520	65 -1.6	0.355 +0.03	49 -3.5	3.4 +0.9	99.6 -2.4	close	8 Ω vs 4 Ω: amp load changes	+
Electro-Voice DL12BFH	60 -6.6	0.307 -0.02	55 +2.5	4 +1.5	100.3 -1.7	close	8 Ω vs 4 Ω: amp load changes	+
Celestion BN12-300S(8)	62.1 -4.5	0.319 -0.01	50 -2.5	2.5 =	97 -5	close	8 Ω vs 4 Ω: amp load changes	+
18 Sound PWX12	61.3 -5.3	0.341 +0.02	56.2 +3.7	2.9 +0.4	98.6 -3.4	close	8 Ω vs 4 Ω: amp load changes	+
RCF L 12/854K	67 +0.4	0.382 +0.06	58 +5.5	3 +0.5	100.1 -1.9	close	8 Ω vs 4 Ω: amp load changes	+
RCF MB 12G300	61 -5.6	0.301 -0.02	57 +4.5	4.3 +1.8	100.1 -1.9	close	8 Ω vs 4 Ω: amp load changes	+
RCF L 12L750	62 -4.6	0.271 -0.05	52 -0.5	3.5 +1	100.2 -1.8	usable	8 Ω vs 4 Ω: amp load changes	+

Compare the closest 3 against the B34D77 →

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.