18 Sound 6NMB420
Thiele-Small parameters
| Nominal size | 6.5" |
|---|---|
| Impedance | 8 Ω |
| Fs | 110 Hz |
| Qts | 0.33 |
| Qes | 0.38 |
| Qms | 2.7 |
| Vas | 6.1 L |
| Sd | 130 cm² |
| Xmax | 3 mm |
| Re | 5.3 Ω |
| Bl | 9 T·m |
| Mms | 8.5 g |
| Pe | 200 W |
| Sensitivity | 100 dB |
Alignment hint
| EBP | 289 · ported |
|---|---|
| Sealed Vb (Qtc ≈ 0.71) | ≈ 1.7 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 6NMB420 | 112 +2 | 0.4 +0.07 | 5.9 -0.2 | 3 = | 100 = | close | 16 Ω vs 8 Ω: amp load changes | + |
| 18 Sound 6NMB900 | 100 -10 | 0.34 +0.01 | 6.65 +0.55 | 3 = | 96 -4 | close | 16 Ω vs 8 Ω: amp load changes | + |
| B&C 6PEV13 | 126 +16 | 0.36 +0.03 | 6 -0.1 | 2.5 -0.5 | 99 -1 | close | 120 W vs 200 W: lower power handling · Xmax 2.5 mm < 3 mm: lower excursion-limited SPL | + |
| B&C 6MBX44 | 113 +3 | 0.31 -0.02 | 4.1 -2 | 3.5 +0.5 | 98 -2 | usable | + | |
| B&C 6MBX44 | 115 +5 | 0.35 +0.02 | 4 -2.1 | 3.5 +0.5 | 98 -2 | usable | 16 Ω vs 8 Ω: amp load changes | + |
| Beyma 6CMV2 | 90 -20 | 0.34 +0.01 | 6.5 +0.4 | 5.7 +2.7 | 94 -6 | usable | + | |
| 18 Sound 6NMB900 | 95 -15 | 0.32 -0.01 | 10.3 +4.2 | 3 = | 97 -3 | usable | + | |
| B&C 6CLA51 | 96 -14 | 0.32 -0.01 | 4.3 -1.8 | 4.8 +1.8 | 94.5 -5.5 | usable | + | |
| Oberton 6M150 | 115.1 +5.1 | 0.422 +0.09 | 5.35 -0.75 | 2.25 -0.75 | 96 -4 | usable | 150 W vs 200 W: lower power handling · Xmax 2.25 mm < 3 mm: lower excursion-limited SPL | + |
| 18 Sound 6ND410 | 120 +10 | 0.24 -0.09 | 6.2 +0.1 | 2 -1 | 102 +2 | usable | Xmax 2 mm < 3 mm: lower excursion-limited SPL | + |
Compare the closest 3 against the 6NMB420 →
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 (9)
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