B&C Speakers B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm
Best box: 12.4 L bass reflex tuned to 77.9 Hz · F3 75.1 Hz
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Comparable 8.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the B&C Speakers B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 12.4 Liters |
| Tuning Frequency (Fb) | 77.9 Hz |
| F3 (-3 dB Cutoff) | 75.1 Hz |
| F6 / F10 Extension | 67.3 Hz / 59.5 Hz |
| Port Inner Diameter | Ø 6.8 cm |
| Port Physical Length | 9.6 cm |
| First Pipe Resonance | 1791.0 Hz |
| Estimated MOL @ F3 | 116.1 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 5.5 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 139.9 Hz |
| F3 (-3 dB Cutoff) | 143.3 Hz |
| F6 / F10 Extension | 106.6 Hz / 79.3 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 74.0 Hz |
| Total Q (Qts) | 0.36 |
| Electrical Q (Qes) | 0.395 |
| Mechanical Q (Qms) | 4.1 |
| Equivalent Volume (Vas) | 15.6 Liters |
| Diaphragm Area (Sd) | 220.0 cm² |
| DC Resistance (Re) | 5.0 Ω |
| Efficiency Bandwidth Product (EBP) | 187.5 |
| Linear Excursion (Xmax) | 5.0 mm |
| Thermal Power (Pe) | 400.0 W |
| Nominal Diameter | 8.0" |
| 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 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm?
Load Forge's calculated alignment puts B&C Speakers B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm in a 12.4 liter vented enclosure tuned to 77.9 Hz, reaching an F3 cutoff of approximately 75.1 Hz.
Can B&C Speakers B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 5.5 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 143.3 Hz.
What port dimensions should be used for B&C Speakers B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 6.8 cm with a length of 9.6 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
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