Focal P 20 FE 20cm
Best box: 18.0 L bass reflex tuned to 27.2 Hz · F3 34.9 Hz
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Comparable 8.4" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Focal P 20 FE 20cm 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
- Port length (76.9 cm) exceeds a straight internal run; use an elbow bend, slotted vent or 3D folded duct to fit the enclosure.
Recommended Bass Reflex (Vented)
PORT NEEDS ELBOW / 3D| Net Box Volume (Vb) | 18.0 Liters |
| Tuning Frequency (Fb) | 27.2 Hz |
| F3 (-3 dB Cutoff) | 34.9 Hz |
| F6 / F10 Extension | 24.9 Hz / 20.8 Hz |
| Port Inner Diameter | Ø 6.8 cm |
| Port Physical Length | 76.9 cm |
| First Pipe Resonance | 224.0 Hz |
| Estimated MOL @ F3 | 103.7 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 20.2 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 48.2 Hz |
| F3 (-3 dB Cutoff) | 45.2 Hz |
| F6 / F10 Extension | 35.3 Hz / 27.2 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 38.5 Hz |
| Total Q (Qts) | 0.56 |
| Electrical Q (Qes) | 0.623 |
| Mechanical Q (Qms) | 5.5 |
| Equivalent Volume (Vas) | 12.0 Liters |
| Diaphragm Area (Sd) | 216.0 cm² |
| DC Resistance (Re) | 4.0 Ω |
| Efficiency Bandwidth Product (EBP) | 61.7 |
| Linear Excursion (Xmax) | 10.0 mm |
| Thermal Power (Pe) | 250.0 W |
| Nominal Diameter | 8.4" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Focal P 20 FE 20cm?
Load Forge's calculated alignment puts Focal P 20 FE 20cm in a 18.0 liter vented enclosure tuned to 27.2 Hz, reaching an F3 cutoff of approximately 34.9 Hz.
Can Focal P 20 FE 20cm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 20.2 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 45.2 Hz.
What port dimensions should be used for Focal P 20 FE 20cm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 6.8 cm with a length of 76.9 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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