B&C Speakers 18SW115
Best box: 70.6 L bass reflex tuned to 48.5 Hz · F3 48.0 Hz
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Comparable 18.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the B&C Speakers 18SW115 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 (70.6 L at 42.2 Hz) would need a 60.6 cm port; the recommendation is retuned to 70.6 L at 48.5 Hz so the port can be built.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 70.6 Liters |
| Tuning Frequency (Fb) | 48.5 Hz |
| F3 (-3 dB Cutoff) | 48.0 Hz |
| F6 / F10 Extension | 43.0 Hz / 37.8 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | 42.4 cm |
| First Pipe Resonance | 406.0 Hz |
| Estimated MOL @ F3 | 124.1 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 32.7 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 77.4 Hz |
| F3 (-3 dB Cutoff) | 78.5 Hz |
| F6 / F10 Extension | 59.1 Hz / 44.5 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 34.0 Hz |
| Total Q (Qts) | 0.3 |
| Electrical Q (Qes) | 0.316 |
| Mechanical Q (Qms) | 6.1 |
| Equivalent Volume (Vas) | 149.1 Liters |
| Diaphragm Area (Sd) | 1210.0 cm² |
| DC Resistance (Re) | 3.3 Ω |
| Efficiency Bandwidth Product (EBP) | 107.8 |
| Linear Excursion (Xmax) | 14.0 mm |
| Thermal Power (Pe) | 1700.0 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 18SW115?
Load Forge's calculated alignment puts B&C Speakers 18SW115 in a 70.6 liter vented enclosure tuned to 48.5 Hz, reaching an F3 cutoff of approximately 48.0 Hz.
Can B&C Speakers 18SW115 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 32.7 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 78.5 Hz.
What port dimensions should be used for B&C Speakers 18SW115 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 20.0 cm with a length of 42.4 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
Embed this design card on DIYAudio, AVSForum, Reddit, or Facebook. It shows the calculated F3, MOL (when the power rating is published) and box parameters.
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