Passive Radiator / Folded Port

SICA 12 K 4 PL

Best box: 6.8 L sealed · Fc 132.7 Hz · F3 123.0 Hz

Predicted SPL response of the SICA 12 K 4 PL in the recommended 6.8 L sealed box versus the alternative — open it in the simulator Open and tweak this box live ↗

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⚠️ Engineering Notice for Builders

  • Straight vent would be 1927.1 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) 13.3 Liters
Tuning Frequency (Fb) 70.9 Hz
F3 (-3 dB Cutoff) 78.7 Hz
F6 / F10 Extension 67.6 Hz / 58.0 Hz
Port Inner Diameter Ø 75.0 cm
Port Physical Length 1927.1 cm
First Pipe Resonance 9.0 Hz
Estimated MOL @ F3 120.9 dB SPL
⚠️ Port feasibility: a straight tube would need 1927.1 cm and cannot fit in a practical cabinet, and no nearby retune stays buildable without a bass hump. Prefer the sealed alignment, a passive radiator, or a 3D folded duct in Load Forge Studio.
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Recommended Sealed (Acoustic Suspension)

MAX TRANSIENT DAMPING
Net Box Volume (Vb) 6.8 Liters
System Q (Qtc) 0.707 (Butterworth)
System Resonance (Fc) 132.7 Hz
F3 (-3 dB Cutoff) 123.0 Hz
F6 / F10 Extension 95.0 Hz / 72.2 Hz
Air Spring Linearity High (Zero port compression)
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Thiele/Small Parameters

Resonance (Fs) 48.5 Hz
Total Q (Qts) 0.25
Electrical Q (Qes) 0.266
Mechanical Q (Qms) 4.2
Equivalent Volume (Vas) 47.4 Liters
Diaphragm Area (Sd) 530.9 cm²
DC Resistance (Re) 5.1 Ω
Efficiency Bandwidth Product (EBP) 182.5
Linear Excursion (Xmax) 321.0 mm
Thermal Power (Pe) 1000.0 W
Nominal Diameter 12.0"
Catalog Source Load Forge catalog (manufacturer datasheets and retailer listings)

Frequently Asked Questions

What is the recommended ported (bass reflex) box volume for SICA 12 K 4 PL?

A simple ported box is not recommended for SICA 12 K 4 PL: the textbook alignment (13.3 liters tuned to 70.9 Hz) needs a 1927.1 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 SICA 12 K 4 PL be used in a sealed box?

Yes. In a sealed (acoustic suspension) enclosure of 6.8 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 123.0 Hz.

What port dimensions should be used for SICA 12 K 4 PL to avoid port chuffing?

A straight 75.0 cm port would need 1927.1 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

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.

SICA 12 K 4 PL Enclosure Card
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