Passive Radiator / Folded Port

SICA 12 PFS 4

Best box: 8.7 L sealed · Fc 103.4 Hz · F3 101.7 Hz

Predicted SPL response of the SICA 12 PFS 4 in the recommended 8.7 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 1888.8 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) 17.5 Liters
Tuning Frequency (Fb) 55.1 Hz
F3 (-3 dB Cutoff) 61.2 Hz
F6 / F10 Extension 52.5 Hz / 45.0 Hz
Port Inner Diameter Ø 66.1 cm
Port Physical Length 1888.8 cm
First Pipe Resonance 9.0 Hz
Estimated MOL @ F3 118.9 dB SPL
⚠️ Port feasibility: a straight tube would need 1888.8 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) 8.7 Liters
System Q (Qtc) 0.707 (Butterworth)
System Resonance (Fc) 103.4 Hz
F3 (-3 dB Cutoff) 101.7 Hz
F6 / F10 Extension 77.3 Hz / 58.3 Hz
Air Spring Linearity High (Zero port compression)
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Thiele/Small Parameters

Resonance (Fs) 39.0 Hz
Total Q (Qts) 0.26
Electrical Q (Qes) 0.276
Mechanical Q (Qms) 4.6
Equivalent Volume (Vas) 55.6 Liters
Diaphragm Area (Sd) 530.9 cm²
DC Resistance (Re) 5.2 Ω
Efficiency Bandwidth Product (EBP) 141.5
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 PFS 4?

A simple ported box is not recommended for SICA 12 PFS 4: the textbook alignment (17.5 liters tuned to 55.1 Hz) needs a 1888.8 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 PFS 4 be used in a sealed box?

Yes. In a sealed (acoustic suspension) enclosure of 8.7 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 101.7 Hz.

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

A straight 66.1 cm port would need 1888.8 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 PFS 4 Enclosure Card
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