Altec ER-12S

12" · 8 Ω · 200 W · 102.6 dB · datasheet ↗

Thiele-Small parameters

Nominal size	12"
Impedance	8 Ω
Fs	70 Hz
Qts	0.251
Qes	0.26
Qms	7.02
Vas	56.6 L
Sd	501.2 cm²
Xmax	2.7 mm
Re	5.2 Ω
Bl	16.8 T·m
Mms	32.1 g
Pe	200 W
Sensitivity	102.6 dB

Alignment hint

EBP	269 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 8.2 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
Electro-Voice EVM-12S PRO LINE	70 =	0.248 =	56.3 -0.3	2.7 =	102.6 =	close		+
PD PD 123ER	60.5 -9.5	0.25 =	51 -5.6	2.5 -0.2	99.9 -2.7	close	Xmax 2.5 mm < 2.7 mm: lower excursion-limited SPL	+
Precision Devices PD 123ER	60.5 -9.5	0.25 =	51 -5.6	2.5 -0.2	99.9 -2.7	close	Xmax 2.5 mm < 2.7 mm: lower excursion-limited SPL	+
RCF L 12L750	62 -8	0.271 +0.02	52 -4.6	3.5 +0.8	100.2 -2.4	usable		+
Peavey 1201-8 v1993	59.7 -10.3	0.269 +0.02	59 +2.4	2.6 -0.1	99.7 -2.9	usable	Xmax 2.6 mm < 2.7 mm: lower excursion-limited SPL	+
RCF 12 CX251	60 -10	0.266 +0.02	62 +5.4	3.7 +1	100.6 -2	usable		+
RCF CX 12N251	60 -10	0.266 +0.02	62 +5.4	3.7 +1	100.6 -2	usable		+
JBL 2020 H	60 -10	0.228 -0.02	65 +8.4	4 +1.3	101.9 -0.7	usable		+
JBL 2020H	60 -10	0.228 -0.02	65 +8.4	4 +1.3	101.9 -0.7	usable		+
Fertin Acoustics B34D77	66.6 -3.4	0.324 +0.07	52.5 -4.1	2.5 -0.2	102 -0.6	usable	4 Ω vs 8 Ω: amp load changes · Xmax 2.5 mm < 2.7 mm: lower excursion-limited SPL	+

Compare the closest 3 against the ER-12S →

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.