Altec 921-8A

15" · 8 Ω · 200 W · 100.1 dB · datasheet ↗

Thiele-Small parameters

Nominal size	15"
Impedance	8 Ω
Fs	34.1 Hz
Qts	0.257
Qes	0.29
Qms	2.24
Vas	299 L
Sd	825.8 cm²
Xmax	5.2 mm
Re	5.1 Ω
Bl	16.2 T·m
Mms	69.6 g
Pe	200 W
Sensitivity	100.1 dB

Alignment hint

EBP	118 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 45.5 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
Focal AUDIOM 15H	34.9 +0.8	0.277 +0.02	295.9 -3.1	5.8 +0.6	99.7 -0.4	close		+
Benett 15.200 Z/N	32.9 -1.2	0.265 +0.01	344 +45	5 -0.2	100.1 =	close	Xmax 5 mm < 5.2 mm: lower excursion-limited SPL	+
Beyma 15GT200 v1990	34 -0.1	0.236 -0.02	276 -23	5 -0.2	99.4 -0.7	close	Xmax 5 mm < 5.2 mm: lower excursion-limited SPL	+
Beyma SM-115	35 +0.9	0.282 +0.02	331 +32	6.7 +1.5	99.7 -0.4	close		+
JBL E145	35 +0.9	0.249 -0.01	274.7 -24.3	4.1 -1.1	100 -0.1	close	150 W vs 200 W: lower power handling · Xmax 4.1 mm < 5.2 mm: lower excursion-limited SPL	+
Fane SOVEREIGN PRO 15-600N	33 -1.1	0.222 -0.04	310 +11	6.5 +1.3	100.5 +0.4	close		+
LaVoce WAF153.02	35 +0.9	0.261 =	244 -55	4.6 -0.6	99.7 -0.4	close	Xmax 4.6 mm < 5.2 mm: lower excursion-limited SPL	+
Eminence KAPPA 15 C	31 -3.1	0.244 -0.01	329.9 +30.9	5.5 +0.3	101.3 +1.2	close	4 Ω vs 8 Ω: amp load changes	+
Beyma 15G350	34 -0.1	0.293 +0.04	302 +3	4.5 -0.7	99 -1.1	close	Xmax 4.5 mm < 5.2 mm: lower excursion-limited SPL	+
Celestion BX15-4085HS8	35 +0.9	0.27 +0.01	247.6 -51.4	6.5 +1.3	99.3 -0.8	close		+

Compare the closest 3 against the 921-8A →

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.