18 Sound 21NLW4100

21" · 8 Ω · 1500 W · 97 dB · datasheet ↗

Thiele-Small parameters

Nominal size	21"
Impedance	8 Ω
Fs	36 Hz
Qts	0.46
Qes	0.49
Qms	7.8
Vas	210 L
Sd	1661 cm²
Xmax	15.2 mm
Re	5.1 Ω
Bl	29.4 T·m
Mms	374 g
Pe	1500 W
Sensitivity	97 dB

Alignment hint

EBP	73 · flexible
Sealed Vb (Qtc ≈ 0.71)	≈ 154.1 L

EBP 50-100: works in either a sealed or ported 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
18 Sound 21NLW4100	34 -2	0.4 -0.06	219 +9	15.2 =	97 =	close	4 Ω vs 8 Ω: amp load changes	+
RCF LF21N551	35 -1	0.33 -0.13	200 -10	15 -0.2	97 =	usable	Xmax 15 mm < 15.2 mm: lower excursion-limited SPL	+
B&C 21SW152	32 -4	0.36 -0.1	200 -10	15 -0.2	96 -1	usable	Xmax 15 mm < 15.2 mm: lower excursion-limited SPL	+
Lavoce SAN215.30	35 -1	0.33 -0.13	200 -10	14.9 -0.3	95.7 -1.3	usable	Xmax 14.9 mm < 15.2 mm: lower excursion-limited SPL	+
Fane Colossus Prime 21NDXL	33 -3	0.36 -0.1	241 +31	14 -1.2	98 +1	usable	Xmax 14 mm < 15.2 mm: lower excursion-limited SPL	+
18 Sound 21LW2600	27 -9	0.37 -0.09	190 -20	14.6 -0.6	97 =	usable	4 Ω vs 8 Ω: amp load changes · Xmax 14.6 mm < 15.2 mm: lower excursion-limited SPL	+
B&C 21SW115	33 -3	0.36 -0.1	278 +68	14 -1.2	97 =	usable	4 Ω vs 8 Ω: amp load changes · Xmax 14 mm < 15.2 mm: lower excursion-limited SPL	+
Fane Colossus Prime 21XS	35 -1	0.339 -0.12	266 +56	14 -1.2	97.5 +0.5	usable	Xmax 14 mm < 15.2 mm: lower excursion-limited SPL	+
18 Sound 21NTLW5000	31 -5	0.36 -0.1	270 +60	17.5 +2.3	97 =	usable		+
B&C 21SW152	32 -4	0.3 -0.16	200 -10	15 -0.2	96 -1	usable	4 Ω vs 8 Ω: amp load changes · Xmax 15 mm < 15.2 mm: lower excursion-limited SPL	+

Compare the closest 3 against the 21NLW4100 →

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.