B&C 6NSM51

6.5" · 8 Ω · 250 W · 100 dB · datasheet ↗

Thiele-Small parameters

Nominal size	6.5"
Impedance	8 Ω
Fs	280 Hz
Qts	0.6
Qes	0.68
Qms	5.4
Vas	0.7 L
Sd	143 cm²
Xmax	2.8 mm
Re	5.4 Ω
Bl	13.9 T·m
Mms	13.5 g
Pe	250 W
Sensitivity	100 dB

Alignment hint

EBP	412 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 1.8 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 6"MCF200Nd	406 +126	0.72 +0.12	0.27 -0.43	2.5 -0.3	97 -3	risky	Xmax 2.5 mm < 2.8 mm: lower excursion-limited SPL	+
B&C 6MD38	150 -130	0.5 -0.1	2.3 +1.6	3.5 +0.7	95 -5	risky	16 Ω vs 8 Ω: amp load changes · 120 W vs 250 W: lower power handling	+
B&C 6MDN44	138 -142	0.47 -0.13	2.8 +2.1	3 +0.2	97 -3	risky	16 Ω vs 8 Ω: amp load changes	+
Beyma 6"MI100	128 -152	0.51 -0.09	3.1 +2.4	3 +0.2	94 -6	risky		+
B&C 6MDN44	140 -140	0.4 -0.2	2.7 +2	2.5 -0.3	96.5 -3.5	risky	Xmax 2.5 mm < 2.8 mm: lower excursion-limited SPL	+
B&C 6MD38	130 -150	0.44 -0.16	3 +2.3	2 -0.8	96 -4	risky	120 W vs 250 W: lower power handling · Xmax 2 mm < 2.8 mm: lower excursion-limited SPL	+
18 Sound 6ND410	149 -131	0.48 -0.12	6.2 +5.5	2 -0.8	102 +2	risky	16 Ω vs 8 Ω: amp load changes · 180 W vs 250 W: lower power handling · Xmax 2 mm < 2.8 mm: lower excursion-limited SPL	+
Oberton 6NM150	124 -156	0.377 -0.22	4 +3.3	2.25 -0.55	97 -3	risky	150 W vs 250 W: lower power handling · Xmax 2.25 mm < 2.8 mm: lower excursion-limited SPL	+
B&C 6MBX44	115 -165	0.35 -0.25	4 +3.3	3.5 +0.7	98 -2	risky	16 Ω vs 8 Ω: amp load changes	+
18 Sound 6NMB420	112 -168	0.4 -0.2	5.9 +5.2	3 +0.2	100 =	risky	16 Ω vs 8 Ω: amp load changes	+

Compare the closest 3 against the 6NSM51 →

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.