B&C Speakers B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm
Best box: 1.9 L bass reflex tuned to 117.6 Hz · F3 287.5 Hz
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Comparable 6.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the B&C Speakers B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- The textbook alignment (1.5 L at 196.0 Hz) would need a 14.0 cm port; the recommendation is retuned to 1.9 L at 117.6 Hz so the port can be built.
- Limited linear excursion (Xmax: 2.8 mm); set a high-pass subsonic filter at 25–30 Hz when driven with high power.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 1.9 Liters |
| Tuning Frequency (Fb) | 117.6 Hz |
| F3 (-3 dB Cutoff) | 287.5 Hz |
| F6 / F10 Extension | 203.7 Hz / 98.5 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 18.8 cm |
| First Pipe Resonance | 914.0 Hz |
| Estimated MOL @ F3 | 119.0 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 1.5 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 319.8 Hz |
| F3 (-3 dB Cutoff) | 328.8 Hz |
| F6 / F10 Extension | 250.0 Hz / 189.6 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 280.0 Hz |
| Total Q (Qts) | 0.6 |
| Electrical Q (Qes) | 0.675 |
| Mechanical Q (Qms) | 5.4 |
| Equivalent Volume (Vas) | 0.6 Liters |
| Diaphragm Area (Sd) | 143.0 cm² |
| DC Resistance (Re) | 5.4 Ω |
| Efficiency Bandwidth Product (EBP) | 414.8 |
| Linear Excursion (Xmax) | 2.8 mm |
| Thermal Power (Pe) | 500.0 W |
| Nominal Diameter | 6.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for B&C Speakers B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm?
Load Forge's calculated alignment puts B&C Speakers B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm in a 1.9 liter vented enclosure tuned to 117.6 Hz, reaching an F3 cutoff of approximately 287.5 Hz.
Can B&C Speakers B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 1.5 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 328.8 Hz.
What port dimensions should be used for B&C Speakers B&C 6NSM51-8 6" Professional Neodymium Sealed Back Midrange 8 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 18.8 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
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