B&C Speakers B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm
Best box: 87.2 L bass reflex tuned to 43.7 Hz · F3 43.1 Hz
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Comparable 18.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the B&C Speakers B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 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 (87.2 L at 39.7 Hz) would need a 54.2 cm port; the recommendation is retuned to 87.2 L at 43.7 Hz so the port can be built.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 87.2 Liters |
| Tuning Frequency (Fb) | 43.7 Hz |
| F3 (-3 dB Cutoff) | 43.1 Hz |
| F6 / F10 Extension | 38.5 Hz / 33.9 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | 42.2 cm |
| First Pipe Resonance | 407.0 Hz |
| Estimated MOL @ F3 | 126.6 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 40.4 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 72.6 Hz |
| F3 (-3 dB Cutoff) | 76.9 Hz |
| F6 / F10 Extension | 57.0 Hz / 42.5 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 32.0 Hz |
| Total Q (Qts) | 0.3 |
| Electrical Q (Qes) | 0.317 |
| Mechanical Q (Qms) | 5.6 |
| Equivalent Volume (Vas) | 184.1 Liters |
| Diaphragm Area (Sd) | 1210.0 cm² |
| DC Resistance (Re) | 5.0 Ω |
| Efficiency Bandwidth Product (EBP) | 101.0 |
| Linear Excursion (Xmax) | 14.0 mm |
| Thermal Power (Pe) | 3400.0 W |
| Nominal Diameter | 18.0" |
| 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 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm?
Load Forge's calculated alignment puts B&C Speakers B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm in a 87.2 liter vented enclosure tuned to 43.7 Hz, reaching an F3 cutoff of approximately 43.1 Hz.
Can B&C Speakers B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 40.4 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 76.9 Hz.
What port dimensions should be used for B&C Speakers B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 20.0 cm with a length of 42.2 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
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Not sure if B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm fits your physical space?
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