RCF LF21N451

21" · 8 Ω · 1500 W · 98.5 dB · datasheet ↗

Thiele-Small parameters

Nominal size	21"
Impedance	8 Ω
Fs	30 Hz
Qts	0.26
Qes	0.27
Qms	6.1
Vas	375 L
Sd	1700 cm²
Xmax	13 mm
Re	5.6 Ω
Bl	34.5 T·m
Mms	315 g
Pe	1500 W
Sensitivity	98.5 dB

Alignment hint

EBP	111 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 58.6 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 21QLEX1600Fe	30 =	0.28 +0.02	309 -66	13 =	98 -0.5	close		+
Beyma 21"LEX1600/Nd	30 =	0.29 +0.03	305 -70	14 +1	98 -0.5	close		+
Faital PRO 21XL3000	30 =	0.25 -0.01	284.6 -90.4	17.67 +4.67	98 -0.5	close		+
18 Sound 21LW1400	28 -2	0.24 -0.02	385 +10	9.5 -3.5	99 +0.5	close	1000 W vs 1500 W: lower power handling · Xmax 9.5 mm < 13 mm: lower excursion-limited SPL	+
18 Sound 21NLW5300	31 +1	0.32 +0.06	325 -50	15.3 +2.3	98.5 =	usable		+
Celestion NTR21-5010JD	30.2 +0.2	0.291 +0.03	341.215 -33.79	9 -4	96.7 -1.8	usable	Xmax 9 mm < 13 mm: lower excursion-limited SPL	+
18 Sound 21NTLW5000	30 =	0.32 +0.06	300 -75	17.5 +4.5	97 -1.5	usable	4 Ω vs 8 Ω: amp load changes	+
RCF LF21N401	30 =	0.37 +0.11	374 -1	11 -2	98 -0.5	usable	Xmax 11 mm < 13 mm: lower excursion-limited SPL	+
18 Sound 21LW2600	27 -3	0.33 +0.07	333 -42	14.6 +1.6	97 -1.5	usable		+
RCF LF21X451	28 -2	0.37 +0.11	385 +10	14 +1	97 -1.5	usable		+

Compare the closest 3 against the LF21N451 →

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.