18 Sound 8NMB420

8" · 4 Ω · 280 W · 95 dB · datasheet ↗

Thiele-Small parameters

Nominal size	8"
Impedance	4 Ω
Fs	59 Hz
Qts	0.31
Qes	0.34
Qms	3.81
Vas	31 L
Sd	227 cm²
Xmax	5.8 mm
Re	2.6 Ω
Bl	7 T·m
Mms	16.9 g
Pe	280 W
Sensitivity	95 dB

Alignment hint

EBP	174 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 7.4 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
18 Sound 8NMB420	61 +2	0.28 -0.03	33 +2	5.8 =	95 =	close	8 Ω vs 4 Ω: amp load changes	+
Beyma 8"P300Fe/N	53 -6	0.31 =	24.8 -6.2	6 +0.2	94 -1	close	8 Ω vs 4 Ω: amp load changes	+
B&C 8MBX51	60 +1	0.29 -0.02	23 -8	6 +0.2	96.5 +1.5	close	8 Ω vs 4 Ω: amp load changes · 200 W vs 280 W: lower power handling	+
18 Sound 8MB400	64 +5	0.38 +0.07	23.9 -7.1	5.8 =	95 =	usable	8 Ω vs 4 Ω: amp load changes	+
Faital PRO 8RS250	56 -3	0.32 +0.01	18.3 -12.7	6.92 +1.12	93 -2	usable	8 Ω vs 4 Ω: amp load changes · 200 W vs 280 W: lower power handling	+
18 Sound 8NMB420	66 +7	0.41 +0.1	24.53 -6.47	5.8 =	95 =	usable	16 Ω vs 4 Ω: amp load changes	+
B&C 8FMB51	67 +8	0.28 -0.03	20.7 -10.3	5.5 -0.3	96.5 +1.5	usable	8 Ω vs 4 Ω: amp load changes · Xmax 5.5 mm < 5.8 mm: lower excursion-limited SPL	+
B&C 8FG51	49 -10	0.32 +0.01	20 -11	6.5 +0.7	93 -2	usable	8 Ω vs 4 Ω: amp load changes	+
18 Sound 8NW650	62 +3	0.25 -0.06	18.99 -12.01	5.5 -0.3	95 =	usable	16 Ω vs 4 Ω: amp load changes · Xmax 5.5 mm < 5.8 mm: lower excursion-limited SPL	+
Sica 8 S 2.5 CP	54 -5	0.33 +0.02	18.6 -12.4	5 -0.8	93 -2	usable	8 Ω vs 4 Ω: amp load changes · Xmax 5 mm < 5.8 mm: lower excursion-limited SPL	+

Compare the closest 3 against the 8NMB420 →

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.