Focal SUB 12 SLIM compatto
Best box: 62.0 L sealed · Fc 33.9 Hz · F3 30.4 Hz
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Comparable 11.8" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Focal SUB 12 SLIM compatto 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
- Xmax is not published, so the port size is an empirical estimate (area ≥ 12 in² per ft³ of net volume, minimum by driver size), not a displacement calculation. Check air velocity in Load Forge Studio.
- Straight vent would be 245.9 cm long: not physically buildable as a simple tube. Use a passive radiator, a folded slot port or model a 3D folded duct in Load Forge Studio.
Textbook Bass Reflex — not recommended
PORT NOT BUILDABLE| Net Box Volume (Vb) | 49.6 Liters |
| Tuning Frequency (Fb) | 20.4 Hz |
| F3 (-3 dB Cutoff) | 30.7 Hz |
| F6 / F10 Extension | 25.2 Hz / 19.2 Hz |
| Port Inner Diameter ESTIMATED | Ø 15.0 cm |
| Port Physical Length | 245.9 cm |
| First Pipe Resonance | 70.0 Hz |
| Estimated MOL @ F3 | 107.1 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.687 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 0.972; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 62.0 Liters |
| System Q (Qtc) | 0.972 (above Butterworth) |
| System Resonance (Fc) | 33.9 Hz |
| F3 (-3 dB Cutoff) | 30.4 Hz |
| F6 / F10 Extension | 24.9 Hz / 19.8 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 24.0 Hz |
| Total Q (Qts) | 0.687 |
| Electrical Q (Qes) | 0.763 |
| Mechanical Q (Qms) | 6.88 |
| Equivalent Volume (Vas) | 62.0 Liters |
| Diaphragm Area (Sd) | 471.0 cm² |
| DC Resistance (Re) | 3.2 Ω |
| Efficiency Bandwidth Product (EBP) | 31.4 |
| Linear Excursion (Xmax) | N/A mm |
| Thermal Power (Pe) | 280.0 W |
| Nominal Diameter | 11.8" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Focal SUB 12 SLIM compatto?
A simple ported box is not recommended for Focal SUB 12 SLIM compatto: the textbook alignment (49.6 liters tuned to 20.4 Hz) needs a 245.9 cm port, and no nearby retune stays buildable without a bass hump. A sealed box, a passive radiator or a folded duct is the practical choice.
Can Focal SUB 12 SLIM compatto be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 62.0 liters with a Qtc of 0.972 (above Butterworth), the system exhibits an F3 of 30.4 Hz.
What port dimensions should be used for Focal SUB 12 SLIM compatto to avoid port chuffing?
A straight 15.0 cm port would need 245.9 cm of length, which does not fit a practical cabinet. Use a passive radiator or a folded/3D duct instead of a straight tube.
Shareable Acoustic Card for Forums & Social Media
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