B&C Speakers B&C 18RBX100-4 18" Professional Subwoofer 4 Ohm
Best box: 147.0 L bass reflex tuned to 40.2 Hz · F3 38.0 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 18RBX100-4 18" Professional 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
- Large enclosure volume (147.0 L) requires extensive internal matrix bracing to prevent panel resonance.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 147.0 Liters |
| Tuning Frequency (Fb) | 40.2 Hz |
| F3 (-3 dB Cutoff) | 38.0 Hz |
| F6 / F10 Extension | 34.2 Hz / 30.4 Hz |
| Port Inner Diameter | Ø 15.0 cm |
| Port Physical Length | 11.6 cm |
| First Pipe Resonance | 1486.0 Hz |
| Estimated MOL @ F3 | 125.1 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 64.0 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 70.8 Hz |
| F3 (-3 dB Cutoff) | 74.7 Hz |
| F6 / F10 Extension | 55.4 Hz / 41.4 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 42.0 Hz |
| Total Q (Qts) | 0.4 |
| Electrical Q (Qes) | 0.421 |
| Mechanical Q (Qms) | 8.0 |
| Equivalent Volume (Vas) | 135.9 Liters |
| Diaphragm Area (Sd) | 1193.1 cm² |
| DC Resistance (Re) | 3.5 Ω |
| Efficiency Bandwidth Product (EBP) | 99.7 |
| Linear Excursion (Xmax) | 10.0 mm |
| Thermal Power (Pe) | 2000.0 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 18RBX100-4 18" Professional Subwoofer 4 Ohm?
Load Forge's calculated alignment puts B&C Speakers B&C 18RBX100-4 18" Professional Subwoofer 4 Ohm in a 147.0 liter vented enclosure tuned to 40.2 Hz, reaching an F3 cutoff of approximately 38.0 Hz.
Can B&C Speakers B&C 18RBX100-4 18" Professional Subwoofer 4 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 64.0 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 74.7 Hz.
What port dimensions should be used for B&C Speakers B&C 18RBX100-4 18" Professional Subwoofer 4 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 15.0 cm with a length of 11.6 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 18RBX100-4 18" Professional Subwoofer 4 Ohm fits your physical space?
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