RCF LF 21N451 v2017

21.5" · 8 Ω · 1500 W · 99.3 dB · datasheet ↗

Thiele-Small parameters

Nominal size	21.5"
Impedance	8 Ω
Fs	30 Hz
Qts	0.259
Qes	0.27
Qms	6.1
Vas	375 L
Sd	1730 cm²
Xmax	8.6 mm
Re	5.6 Ω
Bl	35.1 T·m
Mms	314.9 g
Pe	1500 W
Sensitivity	99.3 dB

Alignment hint

EBP	111 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 58.1 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
Beyma 21LEX1600/Nd	30 =	0.272 +0.01	394 +19	9.3 +0.7	99.3 =	close		+
18 Sound 21LW400	28 -2	0.234 -0.02	385 +10	9.3 +0.7	99.5 +0.2	close		+
RCF LF 21N451	30 =	0.239 -0.02	440 +65	8.9 +0.3	100.4 +1.1	close		+
Beyma 21QLEX1600/Fe	30 =	0.281 +0.02	309 -66	8.4 -0.2	98.1 -1.2	close	Xmax 8.4 mm < 8.6 mm: lower excursion-limited SPL	+
B&C 21 SW 150	29 -1	0.261 =	254 -121	7.5 -1.1	99.4 +0.1	usable	4 Ω vs 8 Ω: amp load changes · Xmax 7.5 mm < 8.6 mm: lower excursion-limited SPL	+
Beyma 21PW1400FE	30 =	0.343 +0.08	401.5 +26.5	10 +1.4	98.6 -0.7	usable		+
PD PDN 2151	31.4 +1.4	0.276 +0.02	303.4 -71.6	6.7 -1.9	99 -0.3	usable	1000 W vs 1500 W: lower power handling · Xmax 6.7 mm < 8.6 mm: lower excursion-limited SPL	+
Precision Devices PDN 2151	31.4 +1.4	0.276 +0.02	303.4 -71.6	6.7 -1.9	99 -0.3	usable	1000 W vs 1500 W: lower power handling · Xmax 6.7 mm < 8.6 mm: lower excursion-limited SPL	+
18 Sound 21NLW9000C	29 -1	0.248 -0.01	257 -118	8.1 -0.5	100.5 +1.2	usable	4 Ω vs 8 Ω: amp load changes · Xmax 8.1 mm < 8.6 mm: lower excursion-limited SPL	+
B&C 21 DS 115	30 =	0.234 -0.02	269 -106	7.6 -1	98.7 -0.6	usable	Xmax 7.6 mm < 8.6 mm: lower excursion-limited SPL	+

Compare the closest 3 against the LF 21N451 v2017 →

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.