B&C 21 DS 115

21.5" · 8 Ω · 1700 W · 98.7 dB · datasheet ↗

Thiele-Small parameters

Nominal size	21.5"
Impedance	8 Ω
Fs	30 Hz
Qts	0.234
Qes	0.24
Qms	10
Vas	269 L
Sd	1680 cm²
Xmax	7.6 mm
Re	5.1 Ω
Bl	40.7 T·m
Mms	414 g
Pe	1700 W
Sensitivity	98.7 dB

Alignment hint

EBP	125 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 33.1 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
LaVoce SAN214.50LD vp	30 =	0.223 -0.01	250 -19	7.2 -0.4	98.4 -0.3	close	Xmax 7.2 mm < 7.6 mm: lower excursion-limited SPL	+
18 Sound 21NLW9000C	29 -1	0.248 +0.01	257 -12	8.1 +0.5	100.5 +1.8	close	4 Ω vs 8 Ω: amp load changes	+
B&C 21 SW 150	29 -1	0.261 +0.03	254 -15	7.5 -0.1	99.4 +0.7	close	4 Ω vs 8 Ω: amp load changes · Xmax 7.5 mm < 7.6 mm: lower excursion-limited SPL	+
Beyma 21QLEX1600/Fe	30 =	0.281 +0.05	309 +40	8.4 +0.8	98.1 -0.6	close		+
18 Sound 21LW400	28 -2	0.234 =	385 +116	9.3 +1.7	99.5 +0.8	usable		+
PD PDN 2151	31.4 +1.4	0.276 +0.04	303.4 +34.4	6.7 -0.9	99 +0.3	usable	1000 W vs 1700 W: lower power handling · Xmax 6.7 mm < 7.6 mm: lower excursion-limited SPL	+
Precision Devices PDN 2151	31.4 +1.4	0.276 +0.04	303.4 +34.4	6.7 -0.9	99 +0.3	usable	1000 W vs 1700 W: lower power handling · Xmax 6.7 mm < 7.6 mm: lower excursion-limited SPL	+
RCF LF 21N451 v2017	30 =	0.259 +0.02	375 +106	8.6 +1	99.3 +0.6	usable		+
Dayton Audio PSS545HE-4 VORTEX	28.8 -1.2	0.27 +0.04	212.1 -56.9	8.6 +1	97.8 -0.9	usable	4 Ω vs 8 Ω: amp load changes	+
B&C 21 DS 115 - 4	30 =	0.196 -0.04	274 +5	6.9 -0.7	103.3 +4.6	usable	4 Ω vs 8 Ω: amp load changes · Xmax 6.9 mm < 7.6 mm: lower excursion-limited SPL	+

Compare the closest 3 against the 21 DS 115 →

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.